// SPDX-License-Identifier: GPL-2.0
/*
 * This file is part of STM32 ADC driver
 *
 * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
 */

#include <linux/array_size.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/timer/stm32-lptim-trigger.h>
#include <linux/iio/timer/stm32-timer-trigger.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/nvmem-consumer.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>

#include "stm32-adc-core.h"

/* Number of linear calibration shadow registers / LINCALRDYW control bits */
#define STM32H7_LINCALFACT_NUM          6

/* BOOST bit must be set on STM32H7 when ADC clock is above 20MHz */
#define STM32H7_BOOST_CLKRATE           20000000UL

#define STM32_ADC_CH_MAX                20      /* max number of channels */
#define STM32_ADC_CH_SZ                 16      /* max channel name size */
#define STM32_ADC_MAX_SQ                16      /* SQ1..SQ16 */
#define STM32_ADC_MAX_SMP               7       /* SMPx range is [0..7] */
#define STM32_ADC_TIMEOUT_US            100000
#define STM32_ADC_TIMEOUT       (msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000))
#define STM32_ADC_HW_STOP_DELAY_MS      100
#define STM32_ADC_VREFINT_VOLTAGE       3300

#define STM32_DMA_BUFFER_SIZE           PAGE_SIZE

/* External trigger enable */
enum stm32_adc_exten {
        STM32_EXTEN_SWTRIG,
        STM32_EXTEN_HWTRIG_RISING_EDGE,
        STM32_EXTEN_HWTRIG_FALLING_EDGE,
        STM32_EXTEN_HWTRIG_BOTH_EDGES,
};

/* extsel - trigger mux selection value */
enum stm32_adc_extsel {
        STM32_EXT0,
        STM32_EXT1,
        STM32_EXT2,
        STM32_EXT3,
        STM32_EXT4,
        STM32_EXT5,
        STM32_EXT6,
        STM32_EXT7,
        STM32_EXT8,
        STM32_EXT9,
        STM32_EXT10,
        STM32_EXT11,
        STM32_EXT12,
        STM32_EXT13,
        STM32_EXT14,
        STM32_EXT15,
        STM32_EXT16,
        STM32_EXT17,
        STM32_EXT18,
        STM32_EXT19,
        STM32_EXT20,
};

enum stm32_adc_int_ch {
        STM32_ADC_INT_CH_NONE = -1,
        STM32_ADC_INT_CH_VDDCORE,
        STM32_ADC_INT_CH_VDDCPU,
        STM32_ADC_INT_CH_VDDQ_DDR,
        STM32_ADC_INT_CH_VREFINT,
        STM32_ADC_INT_CH_VBAT,
        STM32_ADC_INT_CH_NB,
};

/**
 * struct stm32_adc_ic - ADC internal channels
 * @name:       name of the internal channel
 * @idx:        internal channel enum index
 */
struct stm32_adc_ic {
        const char *name;
        u32 idx;
};

static const struct stm32_adc_ic stm32_adc_ic[STM32_ADC_INT_CH_NB] = {
        { "vddcore", STM32_ADC_INT_CH_VDDCORE },
        { "vddcpu", STM32_ADC_INT_CH_VDDCPU },
        { "vddq_ddr", STM32_ADC_INT_CH_VDDQ_DDR },
        { "vrefint", STM32_ADC_INT_CH_VREFINT },
        { "vbat", STM32_ADC_INT_CH_VBAT },
};

/**
 * struct stm32_adc_trig_info - ADC trigger info
 * @name:               name of the trigger, corresponding to its source
 * @extsel:             trigger selection
 */
struct stm32_adc_trig_info {
        const char *name;
        enum stm32_adc_extsel extsel;
};

/**
 * struct stm32_adc_calib - optional adc calibration data
 * @lincalfact: Linearity calibration factor
 * @lincal_saved: Indicates that linear calibration factors are saved
 */
struct stm32_adc_calib {
        u32                     lincalfact[STM32H7_LINCALFACT_NUM];
        bool                    lincal_saved;
};

/**
 * struct stm32_adc_regs - stm32 ADC misc registers & bitfield desc
 * @reg:                register offset
 * @mask:               bitfield mask
 * @shift:              left shift
 */
struct stm32_adc_regs {
        int reg;
        int mask;
        int shift;
};

/**
 * struct stm32_adc_vrefint - stm32 ADC internal reference voltage data
 * @vrefint_cal:        vrefint calibration value from nvmem
 * @vrefint_data:       vrefint actual value
 */
struct stm32_adc_vrefint {
        u32 vrefint_cal;
        u32 vrefint_data;
};

/**
 * struct stm32_adc_regspec - stm32 registers definition
 * @dr:                 data register offset
 * @ier_eoc:            interrupt enable register & eocie bitfield
 * @ier_ovr:            interrupt enable register & overrun bitfield
 * @isr_eoc:            interrupt status register & eoc bitfield
 * @isr_ovr:            interrupt status register & overrun bitfield
 * @sqr:                reference to sequence registers array
 * @exten:              trigger control register & bitfield
 * @extsel:             trigger selection register & bitfield
 * @res:                resolution selection register & bitfield
 * @difsel:             differential mode selection register & bitfield
 * @smpr:               smpr1 & smpr2 registers offset array
 * @smp_bits:           smpr1 & smpr2 index and bitfields
 * @or_vddcore:         option register & vddcore bitfield
 * @or_vddcpu:          option register & vddcpu bitfield
 * @or_vddq_ddr:        option register & vddq_ddr bitfield
 * @ccr_vbat:           common register & vbat bitfield
 * @ccr_vref:           common register & vrefint bitfield
 */
struct stm32_adc_regspec {
        const u32 dr;
        const struct stm32_adc_regs ier_eoc;
        const struct stm32_adc_regs ier_ovr;
        const struct stm32_adc_regs isr_eoc;
        const struct stm32_adc_regs isr_ovr;
        const struct stm32_adc_regs *sqr;
        const struct stm32_adc_regs exten;
        const struct stm32_adc_regs extsel;
        const struct stm32_adc_regs res;
        const struct stm32_adc_regs difsel;
        const u32 smpr[2];
        const struct stm32_adc_regs *smp_bits;
        const struct stm32_adc_regs or_vddcore;
        const struct stm32_adc_regs or_vddcpu;
        const struct stm32_adc_regs or_vddq_ddr;
        const struct stm32_adc_regs ccr_vbat;
        const struct stm32_adc_regs ccr_vref;
};

struct stm32_adc;

/**
 * struct stm32_adc_cfg - stm32 compatible configuration data
 * @regs:               registers descriptions
 * @adc_info:           per instance input channels definitions
 * @trigs:              external trigger sources
 * @clk_required:       clock is required
 * @has_vregready:      vregready status flag presence
 * @has_boostmode:      boost mode support flag
 * @has_linearcal:      linear calibration support flag
 * @has_presel:         channel preselection support flag
 * @has_oversampling:   oversampling support flag
 * @prepare:            optional prepare routine (power-up, enable)
 * @start_conv:         routine to start conversions
 * @stop_conv:          routine to stop conversions
 * @unprepare:          optional unprepare routine (disable, power-down)
 * @irq_clear:          routine to clear irqs
 * @set_ovs:            routine to set oversampling configuration
 * @smp_cycles:         programmable sampling time (ADC clock cycles)
 * @ts_int_ch:          pointer to array of internal channels minimum sampling time in ns
 */
struct stm32_adc_cfg {
        const struct stm32_adc_regspec  *regs;
        const struct stm32_adc_info     *adc_info;
        const struct stm32_adc_trig_info *trigs;
        bool clk_required;
        bool has_vregready;
        bool has_boostmode;
        bool has_linearcal;
        bool has_presel;
        bool has_oversampling;
        int (*prepare)(struct iio_dev *);
        void (*start_conv)(struct iio_dev *, bool dma);
        void (*stop_conv)(struct iio_dev *);
        void (*unprepare)(struct iio_dev *);
        void (*irq_clear)(struct iio_dev *indio_dev, u32 msk);
        void (*set_ovs)(struct iio_dev *indio_dev, u32 ovs_idx);
        const unsigned int *smp_cycles;
        const unsigned int *ts_int_ch;
};

/**
 * struct stm32_adc - private data of each ADC IIO instance
 * @common:             reference to ADC block common data
 * @offset:             ADC instance register offset in ADC block
 * @cfg:                compatible configuration data
 * @completion:         end of single conversion completion
 * @buffer:             data buffer + 8 bytes for timestamp if enabled
 * @clk:                clock for this adc instance
 * @irq:                interrupt for this adc instance
 * @lock:               spinlock
 * @bufi:               data buffer index
 * @num_conv:           expected number of scan conversions
 * @res:                data resolution (e.g. RES bitfield value)
 * @trigger_polarity:   external trigger polarity (e.g. exten)
 * @dma_chan:           dma channel
 * @rx_buf:             dma rx buffer cpu address
 * @rx_dma_buf:         dma rx buffer bus address
 * @rx_buf_sz:          dma rx buffer size
 * @difsel:             bitmask to set single-ended/differential channel
 * @pcsel:              bitmask to preselect channels on some devices
 * @smpr_val:           sampling time settings (e.g. smpr1 / smpr2)
 * @cal:                optional calibration data on some devices
 * @vrefint:            internal reference voltage data
 * @chan_name:          channel name array
 * @num_diff:           number of differential channels
 * @int_ch:             internal channel indexes array
 * @nsmps:              number of channels with optional sample time
 * @ovs_idx:            current oversampling ratio index (in oversampling array)
 */
struct stm32_adc {
        struct stm32_adc_common *common;
        u32                     offset;
        const struct stm32_adc_cfg      *cfg;
        struct completion       completion;
        u16                     buffer[STM32_ADC_MAX_SQ + 4] __aligned(8);
        struct clk              *clk;
        int                     irq;
        spinlock_t              lock;           /* interrupt lock */
        unsigned int            bufi;
        unsigned int            num_conv;
        u32                     res;
        u32                     trigger_polarity;
        struct dma_chan         *dma_chan;
        u8                      *rx_buf;
        dma_addr_t              rx_dma_buf;
        unsigned int            rx_buf_sz;
        u32                     difsel;
        u32                     pcsel;
        u32                     smpr_val[2];
        struct stm32_adc_calib  cal;
        struct stm32_adc_vrefint vrefint;
        char                    chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ];
        u32                     num_diff;
        int                     int_ch[STM32_ADC_INT_CH_NB];
        int                     nsmps;
        int                     ovs_idx;
};

struct stm32_adc_diff_channel {
        u32 vinp;
        u32 vinn;
};

/**
 * struct stm32_adc_info - stm32 ADC, per instance config data
 * @max_channels:       Number of channels
 * @resolutions:        available resolutions
 * @oversampling:       available oversampling ratios
 * @num_res:            number of available resolutions
 * @num_ovs:            number of available oversampling ratios
 */
struct stm32_adc_info {
        int max_channels;
        const unsigned int *resolutions;
        const unsigned int *oversampling;
        const unsigned int num_res;
        const unsigned int num_ovs;
};

static const unsigned int stm32h7_adc_oversampling_avail[] = {
        1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024,
};

static const unsigned int stm32mp13_adc_oversampling_avail[] = {
        1, 2, 4, 8, 16, 32, 64, 128, 256,
};

static const unsigned int stm32f4_adc_resolutions[] = {
        /* sorted values so the index matches RES[1:0] in STM32F4_ADC_CR1 */
        12, 10, 8, 6,
};

/* stm32f4 can have up to 16 channels */
static const struct stm32_adc_info stm32f4_adc_info = {
        .max_channels = 16,
        .resolutions = stm32f4_adc_resolutions,
        .num_res = ARRAY_SIZE(stm32f4_adc_resolutions),
};

static const unsigned int stm32h7_adc_resolutions[] = {
        /* sorted values so the index matches RES[2:0] in STM32H7_ADC_CFGR */
        16, 14, 12, 10, 8,
};

/* stm32h7 can have up to 20 channels */
static const struct stm32_adc_info stm32h7_adc_info = {
        .max_channels = STM32_ADC_CH_MAX,
        .resolutions = stm32h7_adc_resolutions,
        .oversampling = stm32h7_adc_oversampling_avail,
        .num_res = ARRAY_SIZE(stm32h7_adc_resolutions),
        .num_ovs = ARRAY_SIZE(stm32h7_adc_oversampling_avail),
};

/* stm32mp13 can have up to 19 channels */
static const struct stm32_adc_info stm32mp13_adc_info = {
        .max_channels = 19,
        .resolutions = stm32f4_adc_resolutions,
        .oversampling = stm32mp13_adc_oversampling_avail,
        .num_res = ARRAY_SIZE(stm32f4_adc_resolutions),
        .num_ovs = ARRAY_SIZE(stm32mp13_adc_oversampling_avail),
};

/*
 * stm32f4_sq - describe regular sequence registers
 * - L: sequence len (register & bit field)
 * - SQ1..SQ16: sequence entries (register & bit field)
 */
static const struct stm32_adc_regs stm32f4_sq[STM32_ADC_MAX_SQ + 1] = {
        /* L: len bit field description to be kept as first element */
        { STM32F4_ADC_SQR1, GENMASK(23, 20), 20 },
        /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */
        { STM32F4_ADC_SQR3, GENMASK(4, 0), 0 },
        { STM32F4_ADC_SQR3, GENMASK(9, 5), 5 },
        { STM32F4_ADC_SQR3, GENMASK(14, 10), 10 },
        { STM32F4_ADC_SQR3, GENMASK(19, 15), 15 },
        { STM32F4_ADC_SQR3, GENMASK(24, 20), 20 },
        { STM32F4_ADC_SQR3, GENMASK(29, 25), 25 },
        { STM32F4_ADC_SQR2, GENMASK(4, 0), 0 },
        { STM32F4_ADC_SQR2, GENMASK(9, 5), 5 },
        { STM32F4_ADC_SQR2, GENMASK(14, 10), 10 },
        { STM32F4_ADC_SQR2, GENMASK(19, 15), 15 },
        { STM32F4_ADC_SQR2, GENMASK(24, 20), 20 },
        { STM32F4_ADC_SQR2, GENMASK(29, 25), 25 },
        { STM32F4_ADC_SQR1, GENMASK(4, 0), 0 },
        { STM32F4_ADC_SQR1, GENMASK(9, 5), 5 },
        { STM32F4_ADC_SQR1, GENMASK(14, 10), 10 },
        { STM32F4_ADC_SQR1, GENMASK(19, 15), 15 },
};

/* STM32F4 external trigger sources for all instances */
static const struct stm32_adc_trig_info stm32f4_adc_trigs[] = {
        { TIM1_CH1, STM32_EXT0 },
        { TIM1_CH2, STM32_EXT1 },
        { TIM1_CH3, STM32_EXT2 },
        { TIM2_CH2, STM32_EXT3 },
        { TIM2_CH3, STM32_EXT4 },
        { TIM2_CH4, STM32_EXT5 },
        { TIM2_TRGO, STM32_EXT6 },
        { TIM3_CH1, STM32_EXT7 },
        { TIM3_TRGO, STM32_EXT8 },
        { TIM4_CH4, STM32_EXT9 },
        { TIM5_CH1, STM32_EXT10 },
        { TIM5_CH2, STM32_EXT11 },
        { TIM5_CH3, STM32_EXT12 },
        { TIM8_CH1, STM32_EXT13 },
        { TIM8_TRGO, STM32_EXT14 },
        {}, /* sentinel */
};

/*
 * stm32f4_smp_bits[] - describe sampling time register index & bit fields
 * Sorted so it can be indexed by channel number.
 */
static const struct stm32_adc_regs stm32f4_smp_bits[] = {
        /* STM32F4_ADC_SMPR2: smpr[] index, mask, shift for SMP0 to SMP9 */
        { 1, GENMASK(2, 0), 0 },
        { 1, GENMASK(5, 3), 3 },
        { 1, GENMASK(8, 6), 6 },
        { 1, GENMASK(11, 9), 9 },
        { 1, GENMASK(14, 12), 12 },
        { 1, GENMASK(17, 15), 15 },
        { 1, GENMASK(20, 18), 18 },
        { 1, GENMASK(23, 21), 21 },
        { 1, GENMASK(26, 24), 24 },
        { 1, GENMASK(29, 27), 27 },
        /* STM32F4_ADC_SMPR1, smpr[] index, mask, shift for SMP10 to SMP18 */
        { 0, GENMASK(2, 0), 0 },
        { 0, GENMASK(5, 3), 3 },
        { 0, GENMASK(8, 6), 6 },
        { 0, GENMASK(11, 9), 9 },
        { 0, GENMASK(14, 12), 12 },
        { 0, GENMASK(17, 15), 15 },
        { 0, GENMASK(20, 18), 18 },
        { 0, GENMASK(23, 21), 21 },
        { 0, GENMASK(26, 24), 24 },
};

/* STM32F4 programmable sampling time (ADC clock cycles) */
static const unsigned int stm32f4_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
        3, 15, 28, 56, 84, 112, 144, 480,
};

static const struct stm32_adc_regspec stm32f4_adc_regspec = {
        .dr = STM32F4_ADC_DR,
        .ier_eoc = { STM32F4_ADC_CR1, STM32F4_EOCIE },
        .ier_ovr = { STM32F4_ADC_CR1, STM32F4_OVRIE },
        .isr_eoc = { STM32F4_ADC_SR, STM32F4_EOC },
        .isr_ovr = { STM32F4_ADC_SR, STM32F4_OVR },
        .sqr = stm32f4_sq,
        .exten = { STM32F4_ADC_CR2, STM32F4_EXTEN_MASK, STM32F4_EXTEN_SHIFT },
        .extsel = { STM32F4_ADC_CR2, STM32F4_EXTSEL_MASK,
                    STM32F4_EXTSEL_SHIFT },
        .res = { STM32F4_ADC_CR1, STM32F4_RES_MASK, STM32F4_RES_SHIFT },
        .smpr = { STM32F4_ADC_SMPR1, STM32F4_ADC_SMPR2 },
        .smp_bits = stm32f4_smp_bits,
};

static const struct stm32_adc_regs stm32h7_sq[STM32_ADC_MAX_SQ + 1] = {
        /* L: len bit field description to be kept as first element */
        { STM32H7_ADC_SQR1, GENMASK(3, 0), 0 },
        /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */
        { STM32H7_ADC_SQR1, GENMASK(10, 6), 6 },
        { STM32H7_ADC_SQR1, GENMASK(16, 12), 12 },
        { STM32H7_ADC_SQR1, GENMASK(22, 18), 18 },
        { STM32H7_ADC_SQR1, GENMASK(28, 24), 24 },
        { STM32H7_ADC_SQR2, GENMASK(4, 0), 0 },
        { STM32H7_ADC_SQR2, GENMASK(10, 6), 6 },
        { STM32H7_ADC_SQR2, GENMASK(16, 12), 12 },
        { STM32H7_ADC_SQR2, GENMASK(22, 18), 18 },
        { STM32H7_ADC_SQR2, GENMASK(28, 24), 24 },
        { STM32H7_ADC_SQR3, GENMASK(4, 0), 0 },
        { STM32H7_ADC_SQR3, GENMASK(10, 6), 6 },
        { STM32H7_ADC_SQR3, GENMASK(16, 12), 12 },
        { STM32H7_ADC_SQR3, GENMASK(22, 18), 18 },
        { STM32H7_ADC_SQR3, GENMASK(28, 24), 24 },
        { STM32H7_ADC_SQR4, GENMASK(4, 0), 0 },
        { STM32H7_ADC_SQR4, GENMASK(10, 6), 6 },
};

/* STM32H7 external trigger sources for all instances */
static const struct stm32_adc_trig_info stm32h7_adc_trigs[] = {
        { TIM1_CH1, STM32_EXT0 },
        { TIM1_CH2, STM32_EXT1 },
        { TIM1_CH3, STM32_EXT2 },
        { TIM2_CH2, STM32_EXT3 },
        { TIM3_TRGO, STM32_EXT4 },
        { TIM4_CH4, STM32_EXT5 },
        { TIM8_TRGO, STM32_EXT7 },
        { TIM8_TRGO2, STM32_EXT8 },
        { TIM1_TRGO, STM32_EXT9 },
        { TIM1_TRGO2, STM32_EXT10 },
        { TIM2_TRGO, STM32_EXT11 },
        { TIM4_TRGO, STM32_EXT12 },
        { TIM6_TRGO, STM32_EXT13 },
        { TIM15_TRGO, STM32_EXT14 },
        { TIM3_CH4, STM32_EXT15 },
        { LPTIM1_OUT, STM32_EXT18 },
        { LPTIM2_OUT, STM32_EXT19 },
        { LPTIM3_OUT, STM32_EXT20 },
        { }
};

/*
 * stm32h7_smp_bits - describe sampling time register index & bit fields
 * Sorted so it can be indexed by channel number.
 */
static const struct stm32_adc_regs stm32h7_smp_bits[] = {
        /* STM32H7_ADC_SMPR1, smpr[] index, mask, shift for SMP0 to SMP9 */
        { 0, GENMASK(2, 0), 0 },
        { 0, GENMASK(5, 3), 3 },
        { 0, GENMASK(8, 6), 6 },
        { 0, GENMASK(11, 9), 9 },
        { 0, GENMASK(14, 12), 12 },
        { 0, GENMASK(17, 15), 15 },
        { 0, GENMASK(20, 18), 18 },
        { 0, GENMASK(23, 21), 21 },
        { 0, GENMASK(26, 24), 24 },
        { 0, GENMASK(29, 27), 27 },
        /* STM32H7_ADC_SMPR2, smpr[] index, mask, shift for SMP10 to SMP19 */
        { 1, GENMASK(2, 0), 0 },
        { 1, GENMASK(5, 3), 3 },
        { 1, GENMASK(8, 6), 6 },
        { 1, GENMASK(11, 9), 9 },
        { 1, GENMASK(14, 12), 12 },
        { 1, GENMASK(17, 15), 15 },
        { 1, GENMASK(20, 18), 18 },
        { 1, GENMASK(23, 21), 21 },
        { 1, GENMASK(26, 24), 24 },
        { 1, GENMASK(29, 27), 27 },
};

/* STM32H7 programmable sampling time (ADC clock cycles, rounded down) */
static const unsigned int stm32h7_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
        1, 2, 8, 16, 32, 64, 387, 810,
};

static const struct stm32_adc_regspec stm32h7_adc_regspec = {
        .dr = STM32H7_ADC_DR,
        .ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE },
        .ier_ovr = { STM32H7_ADC_IER, STM32H7_OVRIE },
        .isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC },
        .isr_ovr = { STM32H7_ADC_ISR, STM32H7_OVR },
        .sqr = stm32h7_sq,
        .exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT },
        .extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK,
                    STM32H7_EXTSEL_SHIFT },
        .res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT },
        .difsel = { STM32H7_ADC_DIFSEL, STM32H7_DIFSEL_MASK},
        .smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
        .smp_bits = stm32h7_smp_bits,
};

/* STM32MP13 programmable sampling time (ADC clock cycles, rounded down) */
static const unsigned int stm32mp13_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
        2, 6, 12, 24, 47, 92, 247, 640,
};

static const struct stm32_adc_regspec stm32mp13_adc_regspec = {
        .dr = STM32H7_ADC_DR,
        .ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE },
        .ier_ovr = { STM32H7_ADC_IER, STM32H7_OVRIE },
        .isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC },
        .isr_ovr = { STM32H7_ADC_ISR, STM32H7_OVR },
        .sqr = stm32h7_sq,
        .exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT },
        .extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK,
                    STM32H7_EXTSEL_SHIFT },
        .res = { STM32H7_ADC_CFGR, STM32MP13_RES_MASK, STM32MP13_RES_SHIFT },
        .difsel = { STM32MP13_ADC_DIFSEL, STM32MP13_DIFSEL_MASK},
        .smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
        .smp_bits = stm32h7_smp_bits,
        .or_vddcore = { STM32MP13_ADC2_OR, STM32MP13_OP0 },
        .or_vddcpu = { STM32MP13_ADC2_OR, STM32MP13_OP1 },
        .or_vddq_ddr = { STM32MP13_ADC2_OR, STM32MP13_OP2 },
        .ccr_vbat = { STM32H7_ADC_CCR, STM32H7_VBATEN },
        .ccr_vref = { STM32H7_ADC_CCR, STM32H7_VREFEN },
};

static const struct stm32_adc_regspec stm32mp1_adc_regspec = {
        .dr = STM32H7_ADC_DR,
        .ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE },
        .ier_ovr = { STM32H7_ADC_IER, STM32H7_OVRIE },
        .isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC },
        .isr_ovr = { STM32H7_ADC_ISR, STM32H7_OVR },
        .sqr = stm32h7_sq,
        .exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT },
        .extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK,
                    STM32H7_EXTSEL_SHIFT },
        .res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT },
        .difsel = { STM32H7_ADC_DIFSEL, STM32H7_DIFSEL_MASK},
        .smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
        .smp_bits = stm32h7_smp_bits,
        .or_vddcore = { STM32MP1_ADC2_OR, STM32MP1_VDDCOREEN },
        .ccr_vbat = { STM32H7_ADC_CCR, STM32H7_VBATEN },
        .ccr_vref = { STM32H7_ADC_CCR, STM32H7_VREFEN },
};

/*
 * STM32 ADC registers access routines
 * @adc: stm32 adc instance
 * @reg: reg offset in adc instance
 *
 * Note: All instances share same base, with 0x0, 0x100 or 0x200 offset resp.
 * for adc1, adc2 and adc3.
 */
static u32 stm32_adc_readl(struct stm32_adc *adc, u32 reg)
{
        return readl_relaxed(adc->common->base + adc->offset + reg);
}

#define stm32_adc_readl_addr(addr)      stm32_adc_readl(adc, addr)

#define stm32_adc_readl_poll_timeout(reg, val, cond, sleep_us, timeout_us) \
        readx_poll_timeout(stm32_adc_readl_addr, reg, val, \
                           cond, sleep_us, timeout_us)

static u16 stm32_adc_readw(struct stm32_adc *adc, u32 reg)
{
        return readw_relaxed(adc->common->base + adc->offset + reg);
}

static void stm32_adc_writel(struct stm32_adc *adc, u32 reg, u32 val)
{
        writel_relaxed(val, adc->common->base + adc->offset + reg);
}

static void stm32_adc_set_bits(struct stm32_adc *adc, u32 reg, u32 bits)
{
        unsigned long flags;

        spin_lock_irqsave(&adc->lock, flags);
        stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) | bits);
        spin_unlock_irqrestore(&adc->lock, flags);
}

static void stm32_adc_set_bits_common(struct stm32_adc *adc, u32 reg, u32 bits)
{
        spin_lock(&adc->common->lock);
        writel_relaxed(readl_relaxed(adc->common->base + reg) | bits,
                       adc->common->base + reg);
        spin_unlock(&adc->common->lock);
}

static void stm32_adc_clr_bits(struct stm32_adc *adc, u32 reg, u32 bits)
{
        unsigned long flags;

        spin_lock_irqsave(&adc->lock, flags);
        stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) & ~bits);
        spin_unlock_irqrestore(&adc->lock, flags);
}

static void stm32_adc_clr_bits_common(struct stm32_adc *adc, u32 reg, u32 bits)
{
        spin_lock(&adc->common->lock);
        writel_relaxed(readl_relaxed(adc->common->base + reg) & ~bits,
                       adc->common->base + reg);
        spin_unlock(&adc->common->lock);
}

/**
 * stm32_adc_conv_irq_enable() - Enable end of conversion interrupt
 * @adc: stm32 adc instance
 */
static void stm32_adc_conv_irq_enable(struct stm32_adc *adc)
{
        stm32_adc_set_bits(adc, adc->cfg->regs->ier_eoc.reg,
                           adc->cfg->regs->ier_eoc.mask);
};

/**
 * stm32_adc_conv_irq_disable() - Disable end of conversion interrupt
 * @adc: stm32 adc instance
 */
static void stm32_adc_conv_irq_disable(struct stm32_adc *adc)
{
        stm32_adc_clr_bits(adc, adc->cfg->regs->ier_eoc.reg,
                           adc->cfg->regs->ier_eoc.mask);
}

static void stm32_adc_ovr_irq_enable(struct stm32_adc *adc)
{
        stm32_adc_set_bits(adc, adc->cfg->regs->ier_ovr.reg,
                           adc->cfg->regs->ier_ovr.mask);
}

static void stm32_adc_ovr_irq_disable(struct stm32_adc *adc)
{
        stm32_adc_clr_bits(adc, adc->cfg->regs->ier_ovr.reg,
                           adc->cfg->regs->ier_ovr.mask);
}

static void stm32_adc_set_res(struct stm32_adc *adc)
{
        const struct stm32_adc_regs *res = &adc->cfg->regs->res;
        u32 val;

        val = stm32_adc_readl(adc, res->reg);
        val = (val & ~res->mask) | (adc->res << res->shift);
        stm32_adc_writel(adc, res->reg, val);
}

static int stm32_adc_hw_stop(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct stm32_adc *adc = iio_priv(indio_dev);

        if (adc->cfg->unprepare)
                adc->cfg->unprepare(indio_dev);

        clk_disable_unprepare(adc->clk);

        return 0;
}

static int stm32_adc_hw_start(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;

        ret = clk_prepare_enable(adc->clk);
        if (ret)
                return ret;

        stm32_adc_set_res(adc);

        if (adc->cfg->prepare) {
                ret = adc->cfg->prepare(indio_dev);
                if (ret)
                        goto err_clk_dis;
        }

        return 0;

err_clk_dis:
        clk_disable_unprepare(adc->clk);

        return ret;
}

static void stm32_adc_int_ch_enable(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        u32 i;

        for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
                if (adc->int_ch[i] == STM32_ADC_INT_CH_NONE)
                        continue;

                switch (i) {
                case STM32_ADC_INT_CH_VDDCORE:
                        dev_dbg(&indio_dev->dev, "Enable VDDCore\n");
                        stm32_adc_set_bits(adc, adc->cfg->regs->or_vddcore.reg,
                                           adc->cfg->regs->or_vddcore.mask);
                        break;
                case STM32_ADC_INT_CH_VDDCPU:
                        dev_dbg(&indio_dev->dev, "Enable VDDCPU\n");
                        stm32_adc_set_bits(adc, adc->cfg->regs->or_vddcpu.reg,
                                           adc->cfg->regs->or_vddcpu.mask);
                        break;
                case STM32_ADC_INT_CH_VDDQ_DDR:
                        dev_dbg(&indio_dev->dev, "Enable VDDQ_DDR\n");
                        stm32_adc_set_bits(adc, adc->cfg->regs->or_vddq_ddr.reg,
                                           adc->cfg->regs->or_vddq_ddr.mask);
                        break;
                case STM32_ADC_INT_CH_VREFINT:
                        dev_dbg(&indio_dev->dev, "Enable VREFInt\n");
                        stm32_adc_set_bits_common(adc, adc->cfg->regs->ccr_vref.reg,
                                                  adc->cfg->regs->ccr_vref.mask);
                        break;
                case STM32_ADC_INT_CH_VBAT:
                        dev_dbg(&indio_dev->dev, "Enable VBAT\n");
                        stm32_adc_set_bits_common(adc, adc->cfg->regs->ccr_vbat.reg,
                                                  adc->cfg->regs->ccr_vbat.mask);
                        break;
                }
        }
}

static void stm32_adc_int_ch_disable(struct stm32_adc *adc)
{
        u32 i;

        for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
                if (adc->int_ch[i] == STM32_ADC_INT_CH_NONE)
                        continue;

                switch (i) {
                case STM32_ADC_INT_CH_VDDCORE:
                        stm32_adc_clr_bits(adc, adc->cfg->regs->or_vddcore.reg,
                                           adc->cfg->regs->or_vddcore.mask);
                        break;
                case STM32_ADC_INT_CH_VDDCPU:
                        stm32_adc_clr_bits(adc, adc->cfg->regs->or_vddcpu.reg,
                                           adc->cfg->regs->or_vddcpu.mask);
                        break;
                case STM32_ADC_INT_CH_VDDQ_DDR:
                        stm32_adc_clr_bits(adc, adc->cfg->regs->or_vddq_ddr.reg,
                                           adc->cfg->regs->or_vddq_ddr.mask);
                        break;
                case STM32_ADC_INT_CH_VREFINT:
                        stm32_adc_clr_bits_common(adc, adc->cfg->regs->ccr_vref.reg,
                                                  adc->cfg->regs->ccr_vref.mask);
                        break;
                case STM32_ADC_INT_CH_VBAT:
                        stm32_adc_clr_bits_common(adc, adc->cfg->regs->ccr_vbat.reg,
                                                  adc->cfg->regs->ccr_vbat.mask);
                        break;
                }
        }
}

/**
 * stm32f4_adc_start_conv() - Start conversions for regular channels.
 * @indio_dev: IIO device instance
 * @dma: use dma to transfer conversion result
 *
 * Start conversions for regular channels.
 * Also take care of normal or DMA mode. Circular DMA may be used for regular
 * conversions, in IIO buffer modes. Otherwise, use ADC interrupt with direct
 * DR read instead (e.g. read_raw, or triggered buffer mode without DMA).
 */
static void stm32f4_adc_start_conv(struct iio_dev *indio_dev, bool dma)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        stm32_adc_set_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);

        if (dma)
                stm32_adc_set_bits(adc, STM32F4_ADC_CR2,
                                   STM32F4_DMA | STM32F4_DDS);

        stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_EOCS | STM32F4_ADON);

        /* Wait for Power-up time (tSTAB from datasheet) */
        usleep_range(2, 3);

        /* Software start ? (e.g. trigger detection disabled ?) */
        if (!(stm32_adc_readl(adc, STM32F4_ADC_CR2) & STM32F4_EXTEN_MASK))
                stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_SWSTART);
}

static void stm32f4_adc_stop_conv(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, STM32F4_EXTEN_MASK);
        stm32_adc_clr_bits(adc, STM32F4_ADC_SR, STM32F4_STRT);

        stm32_adc_clr_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);
        stm32_adc_clr_bits(adc, STM32F4_ADC_CR2,
                           STM32F4_ADON | STM32F4_DMA | STM32F4_DDS);
}

static void stm32f4_adc_irq_clear(struct iio_dev *indio_dev, u32 msk)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        stm32_adc_clr_bits(adc, adc->cfg->regs->isr_eoc.reg, msk);
}

static void stm32h7_adc_start_conv(struct iio_dev *indio_dev, bool dma)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        enum stm32h7_adc_dmngt dmngt;
        unsigned long flags;
        u32 val;

        if (dma)
                dmngt = STM32H7_DMNGT_DMA_CIRC;
        else
                dmngt = STM32H7_DMNGT_DR_ONLY;

        spin_lock_irqsave(&adc->lock, flags);
        val = stm32_adc_readl(adc, STM32H7_ADC_CFGR);
        val = (val & ~STM32H7_DMNGT_MASK) | (dmngt << STM32H7_DMNGT_SHIFT);
        stm32_adc_writel(adc, STM32H7_ADC_CFGR, val);
        spin_unlock_irqrestore(&adc->lock, flags);

        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART);
}

static void stm32h7_adc_stop_conv(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;
        u32 val;

        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTP);

        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                           !(val & (STM32H7_ADSTART)),
                                           100, STM32_ADC_TIMEOUT_US);
        if (ret)
                dev_warn(&indio_dev->dev, "stop failed\n");

        /* STM32H7_DMNGT_MASK covers STM32MP13_DMAEN & STM32MP13_DMACFG */
        stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK);
}

static void stm32h7_adc_irq_clear(struct iio_dev *indio_dev, u32 msk)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        /* On STM32H7 IRQs are cleared by writing 1 into ISR register */
        stm32_adc_set_bits(adc, adc->cfg->regs->isr_eoc.reg, msk);
}

static void stm32mp13_adc_start_conv(struct iio_dev *indio_dev, bool dma)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        if (dma)
                stm32_adc_set_bits(adc, STM32H7_ADC_CFGR,
                                   STM32MP13_DMAEN | STM32MP13_DMACFG);

        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART);
}

static void stm32h7_adc_set_ovs(struct iio_dev *indio_dev, u32 ovs_idx)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        u32 ovsr_bits, bits, msk;

        msk = STM32H7_ROVSE | STM32H7_OVSR_MASK | STM32H7_OVSS_MASK;
        stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR2, msk);

        if (!ovs_idx)
                return;

        /*
         * Only the oversampling ratios corresponding to 2^ovs_idx are exposed in sysfs.
         * Oversampling ratios [2,3,...,1024] are mapped on OVSR register values [1,2,...,1023].
         * OVSR = 2^ovs_idx - 1
         * These ratio increase the resolution by ovs_idx bits. Apply a right shift to keep initial
         * resolution given by "assigned-resolution-bits" property.
         * OVSS = ovs_idx
         */
        ovsr_bits = GENMASK(ovs_idx - 1, 0);
        bits = STM32H7_ROVSE | STM32H7_OVSS(ovs_idx) | STM32H7_OVSR(ovsr_bits);

        stm32_adc_set_bits(adc, STM32H7_ADC_CFGR2, bits & msk);
}

static void stm32mp13_adc_set_ovs(struct iio_dev *indio_dev, u32 ovs_idx)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        u32 bits, msk;

        msk = STM32H7_ROVSE | STM32MP13_OVSR_MASK | STM32MP13_OVSS_MASK;
        stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR2, msk);

        if (!ovs_idx)
                return;

        /*
         * The oversampling ratios [2,4,8,..,256] are mapped on OVSR register values [0,1,...,7].
         * OVSR = ovs_idx - 1
         * These ratio increase the resolution by ovs_idx bits. Apply a right shift to keep initial
         * resolution given by "assigned-resolution-bits" property.
         * OVSS = ovs_idx
         */
        bits = STM32H7_ROVSE | STM32MP13_OVSS(ovs_idx);
        if (ovs_idx - 1)
                bits |= STM32MP13_OVSR(ovs_idx - 1);

        stm32_adc_set_bits(adc, STM32H7_ADC_CFGR2, bits & msk);
}

static int stm32h7_adc_exit_pwr_down(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;
        u32 val;

        /* Exit deep power down, then enable ADC voltage regulator */
        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN);

        if (adc->cfg->has_boostmode &&
            adc->common->rate > STM32H7_BOOST_CLKRATE)
                stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);

        /* Wait for startup time */
        if (!adc->cfg->has_vregready) {
                usleep_range(10, 20);
                return 0;
        }

        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val,
                                           val & STM32MP1_VREGREADY, 100,
                                           STM32_ADC_TIMEOUT_US);
        if (ret) {
                stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
                dev_err(&indio_dev->dev, "Failed to exit power down\n");
        }

        return ret;
}

static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc)
{
        if (adc->cfg->has_boostmode)
                stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);

        /* Setting DEEPPWD disables ADC vreg and clears ADVREGEN */
        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
}

static int stm32h7_adc_enable(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;
        u32 val;

        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);

        /* Poll for ADRDY to be set (after adc startup time) */
        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val,
                                           val & STM32H7_ADRDY,
                                           100, STM32_ADC_TIMEOUT_US);
        if (ret) {
                stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
                dev_err(&indio_dev->dev, "Failed to enable ADC\n");
        } else {
                /* Clear ADRDY by writing one */
                stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
        }

        return ret;
}

static void stm32h7_adc_disable(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;
        u32 val;

        if (!(stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_ADEN))
                return;

        /* Disable ADC and wait until it's effectively disabled */
        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                           !(val & STM32H7_ADEN), 100,
                                           STM32_ADC_TIMEOUT_US);
        if (ret)
                dev_warn(&indio_dev->dev, "Failed to disable\n");
}

/**
 * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result
 * @indio_dev: IIO device instance
 * Note: Must be called once ADC is enabled, so LINCALRDYW[1..6] are writable
 */
static int stm32h7_adc_read_selfcalib(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int i, ret;
        u32 lincalrdyw_mask, val;

        /* Read linearity calibration */
        lincalrdyw_mask = STM32H7_LINCALRDYW6;
        for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
                /* Clear STM32H7_LINCALRDYW[6..1]: transfer calib to CALFACT2 */
                stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);

                /* Poll: wait calib data to be ready in CALFACT2 register */
                ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                                   !(val & lincalrdyw_mask),
                                                   100, STM32_ADC_TIMEOUT_US);
                if (ret) {
                        dev_err(&indio_dev->dev, "Failed to read calfact\n");
                        return ret;
                }

                val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
                adc->cal.lincalfact[i] = (val & STM32H7_LINCALFACT_MASK);
                adc->cal.lincalfact[i] >>= STM32H7_LINCALFACT_SHIFT;

                lincalrdyw_mask >>= 1;
        }
        adc->cal.lincal_saved = true;

        return 0;
}

/**
 * stm32h7_adc_restore_selfcalib() - Restore saved self-calibration result
 * @indio_dev: IIO device instance
 * Note: ADC must be enabled, with no on-going conversions.
 */
static int stm32h7_adc_restore_selfcalib(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int i, ret;
        u32 lincalrdyw_mask, val;

        lincalrdyw_mask = STM32H7_LINCALRDYW6;
        for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
                /*
                 * Write saved calibration data to shadow registers:
                 * Write CALFACT2, and set LINCALRDYW[6..1] bit to trigger
                 * data write. Then poll to wait for complete transfer.
                 */
                val = adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT;
                stm32_adc_writel(adc, STM32H7_ADC_CALFACT2, val);
                stm32_adc_set_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
                ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                                   val & lincalrdyw_mask,
                                                   100, STM32_ADC_TIMEOUT_US);
                if (ret) {
                        dev_err(&indio_dev->dev, "Failed to write calfact\n");
                        return ret;
                }

                /*
                 * Read back calibration data, has two effects:
                 * - It ensures bits LINCALRDYW[6..1] are kept cleared
                 *   for next time calibration needs to be restored.
                 * - BTW, bit clear triggers a read, then check data has been
                 *   correctly written.
                 */
                stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
                ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                                   !(val & lincalrdyw_mask),
                                                   100, STM32_ADC_TIMEOUT_US);
                if (ret) {
                        dev_err(&indio_dev->dev, "Failed to read calfact\n");
                        return ret;
                }
                val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
                if (val != adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT) {
                        dev_err(&indio_dev->dev, "calfact not consistent\n");
                        return -EIO;
                }

                lincalrdyw_mask >>= 1;
        }

        return 0;
}

/*
 * Fixed timeout value for ADC calibration.
 * worst cases:
 * - low clock frequency
 * - maximum prescalers
 * Calibration requires:
 * - 131,072 ADC clock cycle for the linear calibration
 * - 20 ADC clock cycle for the offset calibration
 *
 * Set to 100ms for now
 */
#define STM32H7_ADC_CALIB_TIMEOUT_US            100000

/**
 * stm32h7_adc_selfcalib() - Procedure to calibrate ADC
 * @indio_dev: IIO device instance
 * @do_lincal: linear calibration request flag
 * Note: Must be called once ADC is out of power down.
 *
 * Run offset calibration unconditionally.
 * Run linear calibration if requested & supported.
 */
static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev, int do_lincal)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;
        u32 msk = STM32H7_ADCALDIF;
        u32 val;

        if (adc->cfg->has_linearcal && do_lincal)
                msk |= STM32H7_ADCALLIN;
        /* ADC must be disabled for calibration */
        stm32h7_adc_disable(indio_dev);

        /*
         * Select calibration mode:
         * - Offset calibration for single ended inputs
         * - No linearity calibration (do it later, before reading it)
         */
        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, msk);

        /* Start calibration, then wait for completion */
        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL);
        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                           !(val & STM32H7_ADCAL), 100,
                                           STM32H7_ADC_CALIB_TIMEOUT_US);
        if (ret) {
                dev_err(&indio_dev->dev, "calibration (single-ended) error %d\n", ret);
                goto out;
        }

        /*
         * Select calibration mode, then start calibration:
         * - Offset calibration for differential input
         * - Linearity calibration (needs to be done only once for single/diff)
         *   will run simultaneously with offset calibration.
         */
        stm32_adc_set_bits(adc, STM32H7_ADC_CR, msk);
        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL);
        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
                                           !(val & STM32H7_ADCAL), 100,
                                           STM32H7_ADC_CALIB_TIMEOUT_US);
        if (ret) {
                dev_err(&indio_dev->dev, "calibration (diff%s) error %d\n",
                        (msk & STM32H7_ADCALLIN) ? "+linear" : "", ret);
                goto out;
        }

out:
        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, msk);

        return ret;
}

/**
 * stm32h7_adc_check_selfcalib() - Check linear calibration status
 * @indio_dev: IIO device instance
 *
 * Used to check if linear calibration has been done.
 * Return true if linear calibration factors are already saved in private data
 * or if a linear calibration has been done at boot stage.
 */
static int stm32h7_adc_check_selfcalib(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        u32 val;

        if (adc->cal.lincal_saved)
                return true;

        /*
         * Check if linear calibration factors are available in ADC registers,
         * by checking that all LINCALRDYWx bits are set.
         */
        val = stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_LINCALRDYW_MASK;
        if (val == STM32H7_LINCALRDYW_MASK)
                return true;

        return false;
}

/**
 * stm32h7_adc_prepare() - Leave power down mode to enable ADC.
 * @indio_dev: IIO device instance
 * Leave power down mode.
 * Configure channels as single ended or differential before enabling ADC.
 * Enable ADC.
 * Restore calibration data.
 * Pre-select channels that may be used in PCSEL (required by input MUX / IO):
 * - Only one input is selected for single ended (e.g. 'vinp')
 * - Two inputs are selected for differential channels (e.g. 'vinp' & 'vinn')
 */
static int stm32h7_adc_prepare(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int lincal_done = false;
        int ret;

        ret = stm32h7_adc_exit_pwr_down(indio_dev);
        if (ret)
                return ret;

        if (adc->cfg->has_linearcal)
                lincal_done = stm32h7_adc_check_selfcalib(indio_dev);

        /* Always run offset calibration. Run linear calibration only once */
        ret = stm32h7_adc_selfcalib(indio_dev, !lincal_done);
        if (ret < 0)
                goto pwr_dwn;

        stm32_adc_int_ch_enable(indio_dev);

        stm32_adc_writel(adc, adc->cfg->regs->difsel.reg, adc->difsel);

        ret = stm32h7_adc_enable(indio_dev);
        if (ret)
                goto ch_disable;

        if (adc->cfg->has_linearcal) {
                if (!adc->cal.lincal_saved)
                        ret = stm32h7_adc_read_selfcalib(indio_dev);
                else
                        ret = stm32h7_adc_restore_selfcalib(indio_dev);

                if (ret)
                        goto disable;
        }

        if (adc->cfg->has_presel)
                stm32_adc_writel(adc, STM32H7_ADC_PCSEL, adc->pcsel);

        return 0;

disable:
        stm32h7_adc_disable(indio_dev);
ch_disable:
        stm32_adc_int_ch_disable(adc);
pwr_dwn:
        stm32h7_adc_enter_pwr_down(adc);

        return ret;
}

static void stm32h7_adc_unprepare(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        if (adc->cfg->has_presel)
                stm32_adc_writel(adc, STM32H7_ADC_PCSEL, 0);
        stm32h7_adc_disable(indio_dev);
        stm32_adc_int_ch_disable(adc);
        stm32h7_adc_enter_pwr_down(adc);
}

/**
 * stm32_adc_conf_scan_seq() - Build regular channels scan sequence
 * @indio_dev: IIO device
 * @scan_mask: channels to be converted
 *
 * Conversion sequence :
 * Apply sampling time settings for all channels.
 * Configure ADC scan sequence based on selected channels in scan_mask.
 * Add channels to SQR registers, from scan_mask LSB to MSB, then
 * program sequence len.
 */
static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev,
                                   const unsigned long *scan_mask)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        const struct stm32_adc_regs *sqr = adc->cfg->regs->sqr;
        const struct iio_chan_spec *chan;
        u32 val, bit;
        int i = 0;

        /* Apply sampling time settings */
        stm32_adc_writel(adc, adc->cfg->regs->smpr[0], adc->smpr_val[0]);
        stm32_adc_writel(adc, adc->cfg->regs->smpr[1], adc->smpr_val[1]);

        for_each_set_bit(bit, scan_mask, iio_get_masklength(indio_dev)) {
                chan = indio_dev->channels + bit;
                /*
                 * Assign one channel per SQ entry in regular
                 * sequence, starting with SQ1.
                 */
                i++;
                if (i > STM32_ADC_MAX_SQ)
                        return -EINVAL;

                dev_dbg(&indio_dev->dev, "%s chan %d to SQ%d\n",
                        __func__, chan->channel, i);

                val = stm32_adc_readl(adc, sqr[i].reg);
                val &= ~sqr[i].mask;
                val |= chan->channel << sqr[i].shift;
                stm32_adc_writel(adc, sqr[i].reg, val);
        }

        if (!i)
                return -EINVAL;

        /* Sequence len */
        val = stm32_adc_readl(adc, sqr[0].reg);
        val &= ~sqr[0].mask;
        val |= ((i - 1) << sqr[0].shift);
        stm32_adc_writel(adc, sqr[0].reg, val);

        return 0;
}

/**
 * stm32_adc_get_trig_extsel() - Get external trigger selection
 * @indio_dev: IIO device structure
 * @trig: trigger
 *
 * Returns trigger extsel value, if trig matches, -EINVAL otherwise.
 */
static int stm32_adc_get_trig_extsel(struct iio_dev *indio_dev,
                                     struct iio_trigger *trig)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int i;

        /* lookup triggers registered by stm32 timer trigger driver */
        for (i = 0; adc->cfg->trigs[i].name; i++) {
                /**
                 * Checking both stm32 timer trigger type and trig name
                 * should be safe against arbitrary trigger names.
                 */
                if ((is_stm32_timer_trigger(trig) ||
                     is_stm32_lptim_trigger(trig)) &&
                    !strcmp(adc->cfg->trigs[i].name, trig->name)) {
                        return adc->cfg->trigs[i].extsel;
                }
        }

        return -EINVAL;
}

/**
 * stm32_adc_set_trig() - Set a regular trigger
 * @indio_dev: IIO device
 * @trig: IIO trigger
 *
 * Set trigger source/polarity (e.g. SW, or HW with polarity) :
 * - if HW trigger disabled (e.g. trig == NULL, conversion launched by sw)
 * - if HW trigger enabled, set source & polarity
 */
static int stm32_adc_set_trig(struct iio_dev *indio_dev,
                              struct iio_trigger *trig)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        u32 val, extsel = 0, exten = STM32_EXTEN_SWTRIG;
        unsigned long flags;
        int ret;

        if (trig) {
                ret = stm32_adc_get_trig_extsel(indio_dev, trig);
                if (ret < 0)
                        return ret;

                /* set trigger source and polarity (default to rising edge) */
                extsel = ret;
                exten = adc->trigger_polarity + STM32_EXTEN_HWTRIG_RISING_EDGE;
        }

        spin_lock_irqsave(&adc->lock, flags);
        val = stm32_adc_readl(adc, adc->cfg->regs->exten.reg);
        val &= ~(adc->cfg->regs->exten.mask | adc->cfg->regs->extsel.mask);
        val |= exten << adc->cfg->regs->exten.shift;
        val |= extsel << adc->cfg->regs->extsel.shift;
        stm32_adc_writel(adc,  adc->cfg->regs->exten.reg, val);
        spin_unlock_irqrestore(&adc->lock, flags);

        return 0;
}

static int stm32_adc_set_trig_pol(struct iio_dev *indio_dev,
                                  const struct iio_chan_spec *chan,
                                  unsigned int type)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        adc->trigger_polarity = type;

        return 0;
}

static int stm32_adc_get_trig_pol(struct iio_dev *indio_dev,
                                  const struct iio_chan_spec *chan)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        return adc->trigger_polarity;
}

static const char * const stm32_trig_pol_items[] = {
        "rising-edge", "falling-edge", "both-edges",
};

static const struct iio_enum stm32_adc_trig_pol = {
        .items = stm32_trig_pol_items,
        .num_items = ARRAY_SIZE(stm32_trig_pol_items),
        .get = stm32_adc_get_trig_pol,
        .set = stm32_adc_set_trig_pol,
};

/**
 * stm32_adc_single_conv() - Performs a single conversion
 * @indio_dev: IIO device
 * @chan: IIO channel
 * @res: conversion result
 *
 * The function performs a single conversion on a given channel:
 * - Apply sampling time settings
 * - Program sequencer with one channel (e.g. in SQ1 with len = 1)
 * - Use SW trigger
 * - Start conversion, then wait for interrupt completion.
 */
static int stm32_adc_single_conv(struct iio_dev *indio_dev,
                                 const struct iio_chan_spec *chan,
                                 int *res)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
        const struct stm32_adc_regspec *regs = adc->cfg->regs;
        long time_left;
        u32 val;
        int ret;

        reinit_completion(&adc->completion);

        adc->bufi = 0;

        ret = pm_runtime_resume_and_get(dev);
        if (ret < 0)
                return ret;

        /* Apply sampling time settings */
        stm32_adc_writel(adc, regs->smpr[0], adc->smpr_val[0]);
        stm32_adc_writel(adc, regs->smpr[1], adc->smpr_val[1]);

        /* Program chan number in regular sequence (SQ1) */
        val = stm32_adc_readl(adc, regs->sqr[1].reg);
        val &= ~regs->sqr[1].mask;
        val |= chan->channel << regs->sqr[1].shift;
        stm32_adc_writel(adc, regs->sqr[1].reg, val);

        /* Set regular sequence len (0 for 1 conversion) */
        stm32_adc_clr_bits(adc, regs->sqr[0].reg, regs->sqr[0].mask);

        /* Trigger detection disabled (conversion can be launched in SW) */
        stm32_adc_clr_bits(adc, regs->exten.reg, regs->exten.mask);

        stm32_adc_conv_irq_enable(adc);

        adc->cfg->start_conv(indio_dev, false);

        time_left = wait_for_completion_interruptible_timeout(
                                        &adc->completion, STM32_ADC_TIMEOUT);
        if (time_left == 0) {
                ret = -ETIMEDOUT;
        } else if (time_left < 0) {
                ret = time_left;
        } else {
                *res = adc->buffer[0];
                ret = IIO_VAL_INT;
        }

        adc->cfg->stop_conv(indio_dev);

        stm32_adc_conv_irq_disable(adc);

        pm_runtime_put_autosuspend(dev);

        return ret;
}

static int stm32_adc_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
        int nb = adc->cfg->adc_info->num_ovs;
        unsigned int idx;
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                if (val2)
                        return -EINVAL;

                for (idx = 0; idx < nb; idx++)
                        if (adc->cfg->adc_info->oversampling[idx] == val)
                                break;
                if (idx >= nb)
                        return -EINVAL;

                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;

                ret = pm_runtime_resume_and_get(dev);
                if (ret < 0)
                        goto err;

                adc->cfg->set_ovs(indio_dev, idx);

                pm_runtime_put_autosuspend(dev);

                adc->ovs_idx = idx;

err:
                iio_device_release_direct(indio_dev);

                return ret;
        default:
                return -EINVAL;
        }
}

static int stm32_adc_read_avail(struct iio_dev *indio_dev,
                                struct iio_chan_spec const *chan,
                                const int **vals, int *type, int *length, long m)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        switch (m) {
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                *type = IIO_VAL_INT;
                *length = adc->cfg->adc_info->num_ovs;
                *vals = adc->cfg->adc_info->oversampling;
                return IIO_AVAIL_LIST;
        default:
                return -EINVAL;
        }
}

static int stm32_adc_read_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int *val, int *val2, long mask)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
        case IIO_CHAN_INFO_PROCESSED:
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                if (chan->type == IIO_VOLTAGE)
                        ret = stm32_adc_single_conv(indio_dev, chan, val);
                else
                        ret = -EINVAL;

                if (mask == IIO_CHAN_INFO_PROCESSED)
                        *val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;

                iio_device_release_direct(indio_dev);
                return ret;

        case IIO_CHAN_INFO_SCALE:
                if (chan->differential) {
                        *val = adc->common->vref_mv * 2;
                        *val2 = chan->scan_type.realbits;
                } else {
                        *val = adc->common->vref_mv;
                        *val2 = chan->scan_type.realbits;
                }
                return IIO_VAL_FRACTIONAL_LOG2;

        case IIO_CHAN_INFO_OFFSET:
                if (chan->differential)
                        /* ADC_full_scale / 2 */
                        *val = -((1 << chan->scan_type.realbits) / 2);
                else
                        *val = 0;
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                *val = adc->cfg->adc_info->oversampling[adc->ovs_idx];
                return IIO_VAL_INT;

        default:
                return -EINVAL;
        }
}

static void stm32_adc_irq_clear(struct iio_dev *indio_dev, u32 msk)
{
        struct stm32_adc *adc = iio_priv(indio_dev);

        adc->cfg->irq_clear(indio_dev, msk);
}

static irqreturn_t stm32_adc_threaded_isr(int irq, void *data)
{
        struct iio_dev *indio_dev = data;
        struct stm32_adc *adc = iio_priv(indio_dev);
        const struct stm32_adc_regspec *regs = adc->cfg->regs;
        u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);

        /* Check ovr status right now, as ovr mask should be already disabled */
        if (status & regs->isr_ovr.mask) {
                /*
                 * Clear ovr bit to avoid subsequent calls to IRQ handler.
                 * This requires to stop ADC first. OVR bit state in ISR,
                 * is propaged to CSR register by hardware.
                 */
                adc->cfg->stop_conv(indio_dev);
                stm32_adc_irq_clear(indio_dev, regs->isr_ovr.mask);
                dev_err(&indio_dev->dev, "Overrun, stopping: restart needed\n");
                return IRQ_HANDLED;
        }

        return IRQ_NONE;
}

static irqreturn_t stm32_adc_isr(int irq, void *data)
{
        struct iio_dev *indio_dev = data;
        struct stm32_adc *adc = iio_priv(indio_dev);
        const struct stm32_adc_regspec *regs = adc->cfg->regs;
        u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);

        if (status & regs->isr_ovr.mask) {
                /*
                 * Overrun occurred on regular conversions: data for wrong
                 * channel may be read. Unconditionally disable interrupts
                 * to stop processing data and print error message.
                 * Restarting the capture can be done by disabling, then
                 * re-enabling it (e.g. write 0, then 1 to buffer/enable).
                 */
                stm32_adc_ovr_irq_disable(adc);
                stm32_adc_conv_irq_disable(adc);
                return IRQ_WAKE_THREAD;
        }

        if (status & regs->isr_eoc.mask) {
                /* Reading DR also clears EOC status flag */
                adc->buffer[adc->bufi] = stm32_adc_readw(adc, regs->dr);
                if (iio_buffer_enabled(indio_dev)) {
                        adc->bufi++;
                        if (adc->bufi >= adc->num_conv) {
                                stm32_adc_conv_irq_disable(adc);
                                iio_trigger_poll(indio_dev->trig);
                        }
                } else {
                        complete(&adc->completion);
                }
                return IRQ_HANDLED;
        }

        return IRQ_NONE;
}

/**
 * stm32_adc_validate_trigger() - validate trigger for stm32 adc
 * @indio_dev: IIO device
 * @trig: new trigger
 *
 * Returns: 0 if trig matches one of the triggers registered by stm32 adc
 * driver, -EINVAL otherwise.
 */
static int stm32_adc_validate_trigger(struct iio_dev *indio_dev,
                                      struct iio_trigger *trig)
{
        return stm32_adc_get_trig_extsel(indio_dev, trig) < 0 ? -EINVAL : 0;
}

static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        unsigned int watermark = STM32_DMA_BUFFER_SIZE / 2;
        unsigned int rx_buf_sz = STM32_DMA_BUFFER_SIZE;

        /*
         * dma cyclic transfers are used, buffer is split into two periods.
         * There should be :
         * - always one buffer (period) dma is working on
         * - one buffer (period) driver can push data.
         */
        watermark = min(watermark, val * (unsigned)(sizeof(u16)));
        adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv);

        return 0;
}

static int stm32_adc_update_scan_mode(struct iio_dev *indio_dev,
                                      const unsigned long *scan_mask)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
        int ret;

        ret = pm_runtime_resume_and_get(dev);
        if (ret < 0)
                return ret;

        adc->num_conv = bitmap_weight(scan_mask, iio_get_masklength(indio_dev));

        ret = stm32_adc_conf_scan_seq(indio_dev, scan_mask);
        pm_runtime_put_autosuspend(dev);

        return ret;
}

static int stm32_adc_fwnode_xlate(struct iio_dev *indio_dev,
                                  const struct fwnode_reference_args *iiospec)
{
        int i;

        for (i = 0; i < indio_dev->num_channels; i++)
                if (indio_dev->channels[i].channel == iiospec->args[0])
                        return i;

        return -EINVAL;
}

/**
 * stm32_adc_debugfs_reg_access - read or write register value
 * @indio_dev: IIO device structure
 * @reg: register offset
 * @writeval: value to write
 * @readval: value to read
 *
 * To read a value from an ADC register:
 *   echo [ADC reg offset] > direct_reg_access
 *   cat direct_reg_access
 *
 * To write a value in a ADC register:
 *   echo [ADC_reg_offset] [value] > direct_reg_access
 */
static int stm32_adc_debugfs_reg_access(struct iio_dev *indio_dev,
                                        unsigned reg, unsigned writeval,
                                        unsigned *readval)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
        int ret;

        ret = pm_runtime_resume_and_get(dev);
        if (ret < 0)
                return ret;

        if (!readval)
                stm32_adc_writel(adc, reg, writeval);
        else
                *readval = stm32_adc_readl(adc, reg);

        pm_runtime_put_autosuspend(dev);

        return 0;
}

static const struct iio_info stm32_adc_iio_info = {
        .read_raw = stm32_adc_read_raw,
        .write_raw = stm32_adc_write_raw,
        .read_avail = stm32_adc_read_avail,
        .validate_trigger = stm32_adc_validate_trigger,
        .hwfifo_set_watermark = stm32_adc_set_watermark,
        .update_scan_mode = stm32_adc_update_scan_mode,
        .debugfs_reg_access = stm32_adc_debugfs_reg_access,
        .fwnode_xlate = stm32_adc_fwnode_xlate,
};

static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc)
{
        struct dma_tx_state state;
        enum dma_status status;

        status = dmaengine_tx_status(adc->dma_chan,
                                     adc->dma_chan->cookie,
                                     &state);
        if (status == DMA_IN_PROGRESS) {
                /* Residue is size in bytes from end of buffer */
                unsigned int i = adc->rx_buf_sz - state.residue;
                unsigned int size;

                /* Return available bytes */
                if (i >= adc->bufi)
                        size = i - adc->bufi;
                else
                        size = adc->rx_buf_sz + i - adc->bufi;

                return size;
        }

        return 0;
}

static void stm32_adc_dma_buffer_done(void *data)
{
        struct iio_dev *indio_dev = data;
        struct stm32_adc *adc = iio_priv(indio_dev);
        int residue = stm32_adc_dma_residue(adc);

        /*
         * In DMA mode the trigger services of IIO are not used
         * (e.g. no call to iio_trigger_poll).
         * Calling irq handler associated to the hardware trigger is not
         * relevant as the conversions have already been done. Data
         * transfers are performed directly in DMA callback instead.
         * This implementation avoids to call trigger irq handler that
         * may sleep, in an atomic context (DMA irq handler context).
         */
        dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);

        while (residue >= indio_dev->scan_bytes) {
                u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];

                iio_push_to_buffers(indio_dev, buffer);

                residue -= indio_dev->scan_bytes;
                adc->bufi += indio_dev->scan_bytes;
                if (adc->bufi >= adc->rx_buf_sz)
                        adc->bufi = 0;
        }
}

static int stm32_adc_dma_start(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct dma_async_tx_descriptor *desc;
        dma_cookie_t cookie;
        int ret;

        if (!adc->dma_chan)
                return 0;

        dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
                adc->rx_buf_sz, adc->rx_buf_sz / 2);

        /* Prepare a DMA cyclic transaction */
        desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
                                         adc->rx_dma_buf,
                                         adc->rx_buf_sz, adc->rx_buf_sz / 2,
                                         DMA_DEV_TO_MEM,
                                         DMA_PREP_INTERRUPT);
        if (!desc)
                return -EBUSY;

        desc->callback = stm32_adc_dma_buffer_done;
        desc->callback_param = indio_dev;

        cookie = dmaengine_submit(desc);
        ret = dma_submit_error(cookie);
        if (ret) {
                dmaengine_terminate_sync(adc->dma_chan);
                return ret;
        }

        /* Issue pending DMA requests */
        dma_async_issue_pending(adc->dma_chan);

        return 0;
}

static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
        int ret;

        ret = pm_runtime_resume_and_get(dev);
        if (ret < 0)
                return ret;

        ret = stm32_adc_set_trig(indio_dev, indio_dev->trig);
        if (ret) {
                dev_err(&indio_dev->dev, "Can't set trigger\n");
                goto err_pm_put;
        }

        ret = stm32_adc_dma_start(indio_dev);
        if (ret) {
                dev_err(&indio_dev->dev, "Can't start dma\n");
                goto err_clr_trig;
        }

        /* Reset adc buffer index */
        adc->bufi = 0;

        stm32_adc_ovr_irq_enable(adc);

        if (!adc->dma_chan)
                stm32_adc_conv_irq_enable(adc);

        adc->cfg->start_conv(indio_dev, !!adc->dma_chan);

        return 0;

err_clr_trig:
        stm32_adc_set_trig(indio_dev, NULL);
err_pm_put:
        pm_runtime_put_autosuspend(dev);

        return ret;
}

static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;

        adc->cfg->stop_conv(indio_dev);
        if (!adc->dma_chan)
                stm32_adc_conv_irq_disable(adc);

        stm32_adc_ovr_irq_disable(adc);

        if (adc->dma_chan)
                dmaengine_terminate_sync(adc->dma_chan);

        if (stm32_adc_set_trig(indio_dev, NULL))
                dev_err(&indio_dev->dev, "Can't clear trigger\n");

        pm_runtime_put_autosuspend(dev);

        return 0;
}

static const struct iio_buffer_setup_ops stm32_adc_buffer_setup_ops = {
        .postenable = &stm32_adc_buffer_postenable,
        .predisable = &stm32_adc_buffer_predisable,
};

static irqreturn_t stm32_adc_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct stm32_adc *adc = iio_priv(indio_dev);

        dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);

        /* reset buffer index */
        adc->bufi = 0;
        iio_push_to_buffers_with_ts(indio_dev, adc->buffer, sizeof(adc->buffer),
                                    pf->timestamp);
        iio_trigger_notify_done(indio_dev->trig);

        /* re-enable eoc irq */
        stm32_adc_conv_irq_enable(adc);

        return IRQ_HANDLED;
}

static const struct iio_chan_spec_ext_info stm32_adc_ext_info[] = {
        IIO_ENUM("trigger_polarity", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
        {
                .name = "trigger_polarity_available",
                .shared = IIO_SHARED_BY_ALL,
                .read = iio_enum_available_read,
                .private = (uintptr_t)&stm32_adc_trig_pol,
        },
        { }
};

static void stm32_adc_debugfs_init(struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct dentry *d = iio_get_debugfs_dentry(indio_dev);
        struct stm32_adc_calib *cal = &adc->cal;
        char buf[16];
        unsigned int i;

        if (!adc->cfg->has_linearcal)
                return;

        for (i = 0; i < STM32H7_LINCALFACT_NUM; i++) {
                snprintf(buf, sizeof(buf), "lincalfact%d", i + 1);
                debugfs_create_u32(buf, 0444, d, &cal->lincalfact[i]);
        }
}

static int stm32_adc_fw_get_resolution(struct iio_dev *indio_dev)
{
        struct device *dev = &indio_dev->dev;
        struct stm32_adc *adc = iio_priv(indio_dev);
        unsigned int i;
        u32 res;

        if (device_property_read_u32(dev, "assigned-resolution-bits", &res))
                res = adc->cfg->adc_info->resolutions[0];

        for (i = 0; i < adc->cfg->adc_info->num_res; i++)
                if (res == adc->cfg->adc_info->resolutions[i])
                        break;
        if (i >= adc->cfg->adc_info->num_res) {
                dev_err(&indio_dev->dev, "Bad resolution: %u bits\n", res);
                return -EINVAL;
        }

        dev_dbg(&indio_dev->dev, "Using %u bits resolution\n", res);
        adc->res = i;

        return 0;
}

static void stm32_adc_smpr_init(struct stm32_adc *adc, int channel, u32 smp_ns)
{
        const struct stm32_adc_regs *smpr = &adc->cfg->regs->smp_bits[channel];
        u32 period_ns, shift = smpr->shift, mask = smpr->mask;
        unsigned int i, smp, r = smpr->reg;

        /*
         * For internal channels, ensure that the sampling time cannot
         * be lower than the one specified in the datasheet
         */
        for (i = 0; i < STM32_ADC_INT_CH_NB; i++)
                if (channel == adc->int_ch[i] && adc->int_ch[i] != STM32_ADC_INT_CH_NONE)
                        smp_ns = max(smp_ns, adc->cfg->ts_int_ch[i]);

        /* Determine sampling time (ADC clock cycles) */
        period_ns = NSEC_PER_SEC / adc->common->rate;
        for (smp = 0; smp <= STM32_ADC_MAX_SMP; smp++)
                if ((period_ns * adc->cfg->smp_cycles[smp]) >= smp_ns)
                        break;
        if (smp > STM32_ADC_MAX_SMP)
                smp = STM32_ADC_MAX_SMP;

        /* pre-build sampling time registers (e.g. smpr1, smpr2) */
        adc->smpr_val[r] = (adc->smpr_val[r] & ~mask) | (smp << shift);
}

static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
                                    struct iio_chan_spec *chan, u32 vinp,
                                    u32 vinn, int scan_index, bool differential)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        char *name = adc->chan_name[vinp];

        chan->type = IIO_VOLTAGE;
        chan->channel = vinp;
        if (differential) {
                chan->differential = 1;
                chan->channel2 = vinn;
                snprintf(name, STM32_ADC_CH_SZ, "in%d-in%d", vinp, vinn);
        } else {
                snprintf(name, STM32_ADC_CH_SZ, "in%d", vinp);
        }
        chan->datasheet_name = name;
        chan->scan_index = scan_index;
        chan->indexed = 1;
        if (chan->channel == adc->int_ch[STM32_ADC_INT_CH_VREFINT])
                chan->info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED);
        else
                chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
        chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
                                         BIT(IIO_CHAN_INFO_OFFSET);
        if (adc->cfg->has_oversampling) {
                chan->info_mask_shared_by_all |= BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
                chan->info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
        }
        chan->scan_type.sign = 'u';
        chan->scan_type.realbits = adc->cfg->adc_info->resolutions[adc->res];
        chan->scan_type.storagebits = 16;
        chan->ext_info = stm32_adc_ext_info;

        /* pre-build selected channels mask */
        adc->pcsel |= BIT(chan->channel);
        if (differential) {
                /* pre-build diff channels mask */
                adc->difsel |= BIT(chan->channel) & adc->cfg->regs->difsel.mask;
                /* Also add negative input to pre-selected channels */
                adc->pcsel |= BIT(chan->channel2);
        }
}

static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm32_adc *adc)
{
        struct device *dev = &indio_dev->dev;
        const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
        int num_channels = 0, ret;

        dev_dbg(&indio_dev->dev, "using legacy channel config\n");

        ret = device_property_count_u32(dev, "st,adc-channels");
        if (ret > adc_info->max_channels) {
                dev_err(&indio_dev->dev, "Bad st,adc-channels?\n");
                return -EINVAL;
        } else if (ret > 0) {
                num_channels += ret;
        }

        /*
         * each st,adc-diff-channels is a group of 2 u32 so we divide @ret
         * to get the *real* number of channels.
         */
        ret = device_property_count_u32(dev, "st,adc-diff-channels");
        if (ret > 0) {
                ret /= (int)(sizeof(struct stm32_adc_diff_channel) / sizeof(u32));
                if (ret > adc_info->max_channels) {
                        dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
                        return -EINVAL;
                } else if (ret > 0) {
                        adc->num_diff = ret;
                        num_channels += ret;
                }
        }

        /* Optional sample time is provided either for each, or all channels */
        adc->nsmps = device_property_count_u32(dev, "st,min-sample-time-nsecs");
        if (adc->nsmps > 1 && adc->nsmps != num_channels) {
                dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n");
                return -EINVAL;
        }

        return num_channels;
}

static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
                                      struct stm32_adc *adc,
                                      struct iio_chan_spec *channels,
                                      int nchans)
{
        const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
        struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
        struct device *dev = &indio_dev->dev;
        u32 num_diff = adc->num_diff;
        int num_se = nchans - num_diff;
        int size = num_diff * sizeof(*diff) / sizeof(u32);
        int scan_index = 0, ret, i, c;
        u32 smp = 0, smps[STM32_ADC_CH_MAX], chans[STM32_ADC_CH_MAX];

        if (num_diff) {
                ret = device_property_read_u32_array(dev, "st,adc-diff-channels",
                                                     (u32 *)diff, size);
                if (ret) {
                        dev_err(&indio_dev->dev, "Failed to get diff channels %d\n", ret);
                        return ret;
                }

                for (i = 0; i < num_diff; i++) {
                        if (diff[i].vinp >= adc_info->max_channels ||
                            diff[i].vinn >= adc_info->max_channels) {
                                dev_err(&indio_dev->dev, "Invalid channel in%d-in%d\n",
                                        diff[i].vinp, diff[i].vinn);
                                return -EINVAL;
                        }

                        stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
                                                diff[i].vinp, diff[i].vinn,
                                                scan_index, true);
                        scan_index++;
                }
        }
        if (num_se > 0) {
                ret = device_property_read_u32_array(dev, "st,adc-channels", chans, num_se);
                if (ret) {
                        dev_err(&indio_dev->dev, "Failed to get st,adc-channels %d\n", ret);
                        return ret;
                }

                for (c = 0; c < num_se; c++) {
                        if (chans[c] >= adc_info->max_channels) {
                                dev_err(&indio_dev->dev, "Invalid channel %d\n",
                                        chans[c]);
                                return -EINVAL;
                        }

                        /* Channel can't be configured both as single-ended & diff */
                        for (i = 0; i < num_diff; i++) {
                                if (chans[c] == diff[i].vinp) {
                                        dev_err(&indio_dev->dev, "channel %d misconfigured\n",
                                                chans[c]);
                                        return -EINVAL;
                                }
                        }
                        stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
                                                chans[c], 0, scan_index, false);
                        scan_index++;
                }
        }

        if (adc->nsmps > 0) {
                ret = device_property_read_u32_array(dev, "st,min-sample-time-nsecs",
                                                     smps, adc->nsmps);
                if (ret)
                        return ret;
        }

        for (i = 0; i < scan_index; i++) {
                /*
                 * This check is used with the above logic so that smp value
                 * will only be modified if valid u32 value can be decoded. This
                 * allows to get either no value, 1 shared value for all indexes,
                 * or one value per channel. The point is to have the same
                 * behavior as 'of_property_read_u32_index()'.
                 */
                if (i < adc->nsmps)
                        smp = smps[i];

                /* Prepare sampling time settings */
                stm32_adc_smpr_init(adc, channels[i].channel, smp);
        }

        return scan_index;
}

static int stm32_adc_populate_int_ch(struct iio_dev *indio_dev, const char *ch_name,
                                     int chan)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        u16 vrefint;
        int i, ret;

        for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
                if (!strncmp(stm32_adc_ic[i].name, ch_name, STM32_ADC_CH_SZ)) {
                        /* Check internal channel availability */
                        switch (i) {
                        case STM32_ADC_INT_CH_VDDCORE:
                                if (!adc->cfg->regs->or_vddcore.reg)
                                        dev_warn(&indio_dev->dev,
                                                 "%s channel not available\n", ch_name);
                                break;
                        case STM32_ADC_INT_CH_VDDCPU:
                                if (!adc->cfg->regs->or_vddcpu.reg)
                                        dev_warn(&indio_dev->dev,
                                                 "%s channel not available\n", ch_name);
                                break;
                        case STM32_ADC_INT_CH_VDDQ_DDR:
                                if (!adc->cfg->regs->or_vddq_ddr.reg)
                                        dev_warn(&indio_dev->dev,
                                                 "%s channel not available\n", ch_name);
                                break;
                        case STM32_ADC_INT_CH_VREFINT:
                                if (!adc->cfg->regs->ccr_vref.reg)
                                        dev_warn(&indio_dev->dev,
                                                 "%s channel not available\n", ch_name);
                                break;
                        case STM32_ADC_INT_CH_VBAT:
                                if (!adc->cfg->regs->ccr_vbat.reg)
                                        dev_warn(&indio_dev->dev,
                                                 "%s channel not available\n", ch_name);
                                break;
                        }

                        if (stm32_adc_ic[i].idx != STM32_ADC_INT_CH_VREFINT) {
                                adc->int_ch[i] = chan;
                                break;
                        }

                        /* Get calibration data for vrefint channel */
                        ret = nvmem_cell_read_u16(&indio_dev->dev, "vrefint", &vrefint);
                        if (ret && ret != -ENOENT) {
                                return dev_err_probe(indio_dev->dev.parent, ret,
                                                     "nvmem access error\n");
                        }
                        if (ret == -ENOENT) {
                                dev_dbg(&indio_dev->dev, "vrefint calibration not found. Skip vrefint channel\n");
                                return ret;
                        } else if (!vrefint) {
                                dev_dbg(&indio_dev->dev, "Null vrefint calibration value. Skip vrefint channel\n");
                                return -ENOENT;
                        }
                        adc->int_ch[i] = chan;
                        adc->vrefint.vrefint_cal = vrefint;
                }
        }

        return 0;
}

static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
                                       struct stm32_adc *adc,
                                       struct iio_chan_spec *channels)
{
        const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
        struct device *dev = &indio_dev->dev;
        const char *name;
        int val, scan_index = 0, ret;
        bool differential;
        u32 vin[2];

        device_for_each_child_node_scoped(dev, child) {
                ret = fwnode_property_read_u32(child, "reg", &val);
                if (ret)
                        return dev_err_probe(dev, ret,
                                             "Missing channel index\n");

                ret = fwnode_property_read_string(child, "label", &name);
                /* label is optional */
                if (!ret) {
                        if (strlen(name) >= STM32_ADC_CH_SZ)
                                return dev_err_probe(dev, -EINVAL,
                                                     "Label %s exceeds %d characters\n",
                                                     name, STM32_ADC_CH_SZ);

                        strscpy(adc->chan_name[val], name, STM32_ADC_CH_SZ);
                        ret = stm32_adc_populate_int_ch(indio_dev, name, val);
                        if (ret == -ENOENT)
                                continue;
                        else if (ret)
                                return ret;
                } else if (ret != -EINVAL) {
                        return dev_err_probe(dev, ret, "Invalid label\n");
                }

                if (val >= adc_info->max_channels)
                        return dev_err_probe(dev, -EINVAL,
                                             "Invalid channel %d\n", val);

                differential = false;
                ret = fwnode_property_read_u32_array(child, "diff-channels", vin, 2);
                /* diff-channels is optional */
                if (!ret) {
                        differential = true;
                        if (vin[0] != val || vin[1] >= adc_info->max_channels)
                                return dev_err_probe(dev, -EINVAL,
                                                     "Invalid channel in%d-in%d\n",
                                                     vin[0], vin[1]);
                } else if (ret != -EINVAL) {
                        return dev_err_probe(dev, ret,
                                             "Invalid diff-channels property\n");
                }

                stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
                                        vin[1], scan_index, differential);

                val = 0;
                ret = fwnode_property_read_u32(child, "st,min-sample-time-ns", &val);
                /* st,min-sample-time-ns is optional */
                if (ret && ret != -EINVAL)
                        return dev_err_probe(dev, ret,
                                             "Invalid st,min-sample-time-ns property\n");

                stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
                if (differential)
                        stm32_adc_smpr_init(adc, vin[1], val);

                scan_index++;
        }

        return scan_index;
}

static int stm32_adc_chan_fw_init(struct iio_dev *indio_dev, bool timestamping)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
        struct iio_chan_spec *channels;
        int scan_index = 0, num_channels = 0, ret, i;
        bool legacy = false;

        for (i = 0; i < STM32_ADC_INT_CH_NB; i++)
                adc->int_ch[i] = STM32_ADC_INT_CH_NONE;

        num_channels = device_get_child_node_count(&indio_dev->dev);
        /* If no channels have been found, fallback to channels legacy properties. */
        if (!num_channels) {
                legacy = true;

                ret = stm32_adc_get_legacy_chan_count(indio_dev, adc);
                if (!ret) {
                        dev_err(indio_dev->dev.parent, "No channel found\n");
                        return -ENODATA;
                } else if (ret < 0) {
                        return ret;
                }

                num_channels = ret;
        }

        if (num_channels > adc_info->max_channels) {
                dev_err(&indio_dev->dev, "Channel number [%d] exceeds %d\n",
                        num_channels, adc_info->max_channels);
                return -EINVAL;
        }

        if (timestamping)
                num_channels++;

        channels = devm_kcalloc(&indio_dev->dev, num_channels,
                                sizeof(struct iio_chan_spec), GFP_KERNEL);
        if (!channels)
                return -ENOMEM;

        if (legacy)
                ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels,
                                                 timestamping ? num_channels - 1 : num_channels);
        else
                ret = stm32_adc_generic_chan_init(indio_dev, adc, channels);
        if (ret < 0)
                return ret;
        scan_index = ret;

        if (timestamping) {
                struct iio_chan_spec *timestamp = &channels[scan_index];

                timestamp->type = IIO_TIMESTAMP;
                timestamp->channel = -1;
                timestamp->scan_index = scan_index;
                timestamp->scan_type.sign = 's';
                timestamp->scan_type.realbits = 64;
                timestamp->scan_type.storagebits = 64;

                scan_index++;
        }

        indio_dev->num_channels = scan_index;
        indio_dev->channels = channels;

        return 0;
}

static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev)
{
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct dma_slave_config config = { };
        int ret;

        adc->dma_chan = dma_request_chan(dev, "rx");
        if (IS_ERR(adc->dma_chan)) {
                ret = PTR_ERR(adc->dma_chan);
                if (ret != -ENODEV)
                        return dev_err_probe(dev, ret,
                                             "DMA channel request failed with\n");

                /* DMA is optional: fall back to IRQ mode */
                adc->dma_chan = NULL;
                return 0;
        }

        adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
                                         STM32_DMA_BUFFER_SIZE,
                                         &adc->rx_dma_buf, GFP_KERNEL);
        if (!adc->rx_buf) {
                ret = -ENOMEM;
                goto err_release;
        }

        /* Configure DMA channel to read data register */
        config.src_addr = (dma_addr_t)adc->common->phys_base;
        config.src_addr += adc->offset + adc->cfg->regs->dr;
        config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;

        ret = dmaengine_slave_config(adc->dma_chan, &config);
        if (ret)
                goto err_free;

        return 0;

err_free:
        dma_free_coherent(adc->dma_chan->device->dev, STM32_DMA_BUFFER_SIZE,
                          adc->rx_buf, adc->rx_dma_buf);
err_release:
        dma_release_channel(adc->dma_chan);

        return ret;
}

static int stm32_adc_probe(struct platform_device *pdev)
{
        struct iio_dev *indio_dev;
        struct device *dev = &pdev->dev;
        irqreturn_t (*handler)(int irq, void *p) = NULL;
        struct stm32_adc *adc;
        bool timestamping = false;
        int ret;

        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
        if (!indio_dev)
                return -ENOMEM;

        adc = iio_priv(indio_dev);
        adc->common = dev_get_drvdata(pdev->dev.parent);
        spin_lock_init(&adc->lock);
        init_completion(&adc->completion);
        adc->cfg = device_get_match_data(dev);

        indio_dev->name = dev_name(&pdev->dev);
        device_set_node(&indio_dev->dev, dev_fwnode(&pdev->dev));
        indio_dev->info = &stm32_adc_iio_info;
        indio_dev->modes = INDIO_DIRECT_MODE | INDIO_HARDWARE_TRIGGERED;

        platform_set_drvdata(pdev, indio_dev);

        ret = device_property_read_u32(dev, "reg", &adc->offset);
        if (ret != 0) {
                dev_err(&pdev->dev, "missing reg property\n");
                return -EINVAL;
        }

        adc->irq = platform_get_irq(pdev, 0);
        if (adc->irq < 0)
                return adc->irq;

        ret = devm_request_threaded_irq(&pdev->dev, adc->irq, stm32_adc_isr,
                                        stm32_adc_threaded_isr,
                                        0, pdev->name, indio_dev);
        if (ret) {
                dev_err(&pdev->dev, "failed to request IRQ\n");
                return ret;
        }

        adc->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(adc->clk)) {
                ret = PTR_ERR(adc->clk);
                if (ret == -ENOENT && !adc->cfg->clk_required) {
                        adc->clk = NULL;
                } else {
                        dev_err(&pdev->dev, "Can't get clock\n");
                        return ret;
                }
        }

        ret = stm32_adc_fw_get_resolution(indio_dev);
        if (ret < 0)
                return ret;

        ret = stm32_adc_dma_request(dev, indio_dev);
        if (ret < 0)
                return ret;

        if (!adc->dma_chan) {
                /* For PIO mode only, iio_pollfunc_store_time stores a timestamp
                 * in the primary trigger IRQ handler and stm32_adc_trigger_handler
                 * runs in the IRQ thread to push out buffer along with timestamp.
                 */
                handler = &stm32_adc_trigger_handler;
                timestamping = true;
        }

        ret = stm32_adc_chan_fw_init(indio_dev, timestamping);
        if (ret < 0)
                goto err_dma_disable;

        ret = iio_triggered_buffer_setup(indio_dev,
                                         &iio_pollfunc_store_time, handler,
                                         &stm32_adc_buffer_setup_ops);
        if (ret) {
                dev_err(&pdev->dev, "buffer setup failed\n");
                goto err_dma_disable;
        }

        /* Get stm32-adc-core PM online */
        pm_runtime_get_noresume(dev);
        pm_runtime_set_active(dev);
        pm_runtime_set_autosuspend_delay(dev, STM32_ADC_HW_STOP_DELAY_MS);
        pm_runtime_use_autosuspend(dev);
        pm_runtime_enable(dev);

        ret = stm32_adc_hw_start(dev);
        if (ret)
                goto err_buffer_cleanup;

        ret = iio_device_register(indio_dev);
        if (ret) {
                dev_err(&pdev->dev, "iio dev register failed\n");
                goto err_hw_stop;
        }

        pm_runtime_put_autosuspend(dev);

        if (IS_ENABLED(CONFIG_DEBUG_FS))
                stm32_adc_debugfs_init(indio_dev);

        return 0;

err_hw_stop:
        stm32_adc_hw_stop(dev);

err_buffer_cleanup:
        pm_runtime_disable(dev);
        pm_runtime_set_suspended(dev);
        pm_runtime_put_noidle(dev);
        iio_triggered_buffer_cleanup(indio_dev);

err_dma_disable:
        if (adc->dma_chan) {
                dma_free_coherent(adc->dma_chan->device->dev,
                                  STM32_DMA_BUFFER_SIZE,
                                  adc->rx_buf, adc->rx_dma_buf);
                dma_release_channel(adc->dma_chan);
        }

        return ret;
}

static void stm32_adc_remove(struct platform_device *pdev)
{
        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
        struct stm32_adc *adc = iio_priv(indio_dev);

        pm_runtime_get_sync(&pdev->dev);
        /* iio_device_unregister() also removes debugfs entries */
        iio_device_unregister(indio_dev);
        stm32_adc_hw_stop(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        pm_runtime_set_suspended(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
        iio_triggered_buffer_cleanup(indio_dev);
        if (adc->dma_chan) {
                dma_free_coherent(adc->dma_chan->device->dev,
                                  STM32_DMA_BUFFER_SIZE,
                                  adc->rx_buf, adc->rx_dma_buf);
                dma_release_channel(adc->dma_chan);
        }
}

static int stm32_adc_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);

        if (iio_buffer_enabled(indio_dev))
                stm32_adc_buffer_predisable(indio_dev);

        return pm_runtime_force_suspend(dev);
}

static int stm32_adc_resume(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        int ret;

        ret = pm_runtime_force_resume(dev);
        if (ret < 0)
                return ret;

        if (!iio_buffer_enabled(indio_dev))
                return 0;

        ret = stm32_adc_update_scan_mode(indio_dev,
                                         indio_dev->active_scan_mask);
        if (ret < 0)
                return ret;

        return stm32_adc_buffer_postenable(indio_dev);
}

static int stm32_adc_runtime_suspend(struct device *dev)
{
        return stm32_adc_hw_stop(dev);
}

static int stm32_adc_runtime_resume(struct device *dev)
{
        return stm32_adc_hw_start(dev);
}

static const struct dev_pm_ops stm32_adc_pm_ops = {
        SYSTEM_SLEEP_PM_OPS(stm32_adc_suspend, stm32_adc_resume)
        RUNTIME_PM_OPS(stm32_adc_runtime_suspend, stm32_adc_runtime_resume,
                       NULL)
};

static const struct stm32_adc_cfg stm32f4_adc_cfg = {
        .regs = &stm32f4_adc_regspec,
        .adc_info = &stm32f4_adc_info,
        .trigs = stm32f4_adc_trigs,
        .clk_required = true,
        .start_conv = stm32f4_adc_start_conv,
        .stop_conv = stm32f4_adc_stop_conv,
        .smp_cycles = stm32f4_adc_smp_cycles,
        .irq_clear = stm32f4_adc_irq_clear,
};

static const unsigned int stm32_adc_min_ts_h7[] = { 0, 0, 0, 4300, 9000 };
static_assert(ARRAY_SIZE(stm32_adc_min_ts_h7) == STM32_ADC_INT_CH_NB);

static const struct stm32_adc_cfg stm32h7_adc_cfg = {
        .regs = &stm32h7_adc_regspec,
        .adc_info = &stm32h7_adc_info,
        .trigs = stm32h7_adc_trigs,
        .has_boostmode = true,
        .has_linearcal = true,
        .has_presel = true,
        .has_oversampling = true,
        .start_conv = stm32h7_adc_start_conv,
        .stop_conv = stm32h7_adc_stop_conv,
        .prepare = stm32h7_adc_prepare,
        .unprepare = stm32h7_adc_unprepare,
        .smp_cycles = stm32h7_adc_smp_cycles,
        .irq_clear = stm32h7_adc_irq_clear,
        .ts_int_ch = stm32_adc_min_ts_h7,
        .set_ovs = stm32h7_adc_set_ovs,
};

static const unsigned int stm32_adc_min_ts_mp1[] = { 100, 100, 100, 4300, 9800 };
static_assert(ARRAY_SIZE(stm32_adc_min_ts_mp1) == STM32_ADC_INT_CH_NB);

static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
        .regs = &stm32mp1_adc_regspec,
        .adc_info = &stm32h7_adc_info,
        .trigs = stm32h7_adc_trigs,
        .has_vregready = true,
        .has_boostmode = true,
        .has_linearcal = true,
        .has_presel = true,
        .has_oversampling = true,
        .start_conv = stm32h7_adc_start_conv,
        .stop_conv = stm32h7_adc_stop_conv,
        .prepare = stm32h7_adc_prepare,
        .unprepare = stm32h7_adc_unprepare,
        .smp_cycles = stm32h7_adc_smp_cycles,
        .irq_clear = stm32h7_adc_irq_clear,
        .ts_int_ch = stm32_adc_min_ts_mp1,
        .set_ovs = stm32h7_adc_set_ovs,
};

static const unsigned int stm32_adc_min_ts_mp13[] = { 100, 0, 0, 4300, 9800 };
static_assert(ARRAY_SIZE(stm32_adc_min_ts_mp13) == STM32_ADC_INT_CH_NB);

static const struct stm32_adc_cfg stm32mp13_adc_cfg = {
        .regs = &stm32mp13_adc_regspec,
        .adc_info = &stm32mp13_adc_info,
        .trigs = stm32h7_adc_trigs,
        .has_oversampling = true,
        .start_conv = stm32mp13_adc_start_conv,
        .stop_conv = stm32h7_adc_stop_conv,
        .prepare = stm32h7_adc_prepare,
        .unprepare = stm32h7_adc_unprepare,
        .smp_cycles = stm32mp13_adc_smp_cycles,
        .irq_clear = stm32h7_adc_irq_clear,
        .ts_int_ch = stm32_adc_min_ts_mp13,
        .set_ovs = stm32mp13_adc_set_ovs,
};

static const struct of_device_id stm32_adc_of_match[] = {
        { .compatible = "st,stm32f4-adc", .data = (void *)&stm32f4_adc_cfg },
        { .compatible = "st,stm32h7-adc", .data = (void *)&stm32h7_adc_cfg },
        { .compatible = "st,stm32mp1-adc", .data = (void *)&stm32mp1_adc_cfg },
        { .compatible = "st,stm32mp13-adc", .data = (void *)&stm32mp13_adc_cfg },
        { }
};
MODULE_DEVICE_TABLE(of, stm32_adc_of_match);

static struct platform_driver stm32_adc_driver = {
        .probe = stm32_adc_probe,
        .remove = stm32_adc_remove,
        .driver = {
                .name = "stm32-adc",
                .of_match_table = stm32_adc_of_match,
                .pm = pm_ptr(&stm32_adc_pm_ops),
        },
};
module_platform_driver(stm32_adc_driver);

MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 ADC IIO driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:stm32-adc");