// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012-2016, The Linux Foundation. All rights reserved.
 */

#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/iio/adc/qcom-vadc-common.h>
#include <linux/iio/iio.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/log2.h>

#include <dt-bindings/iio/qcom,spmi-vadc.h>

/* VADC register and bit definitions */
#define VADC_REVISION2                          0x1
#define VADC_REVISION2_SUPPORTED_VADC           1

#define VADC_PERPH_TYPE                         0x4
#define VADC_PERPH_TYPE_ADC                     8

#define VADC_PERPH_SUBTYPE                      0x5
#define VADC_PERPH_SUBTYPE_VADC                 1

#define VADC_STATUS1                            0x8
#define VADC_STATUS1_OP_MODE                    4
#define VADC_STATUS1_REQ_STS                    BIT(1)
#define VADC_STATUS1_EOC                        BIT(0)
#define VADC_STATUS1_REQ_STS_EOC_MASK           0x3

#define VADC_MODE_CTL                           0x40
#define VADC_OP_MODE_SHIFT                      3
#define VADC_OP_MODE_NORMAL                     0
#define VADC_AMUX_TRIM_EN                       BIT(1)
#define VADC_ADC_TRIM_EN                        BIT(0)

#define VADC_EN_CTL1                            0x46
#define VADC_EN_CTL1_SET                        BIT(7)

#define VADC_ADC_CH_SEL_CTL                     0x48

#define VADC_ADC_DIG_PARAM                      0x50
#define VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT        2

#define VADC_HW_SETTLE_DELAY                    0x51

#define VADC_CONV_REQ                           0x52
#define VADC_CONV_REQ_SET                       BIT(7)

#define VADC_FAST_AVG_CTL                       0x5a
#define VADC_FAST_AVG_EN                        0x5b
#define VADC_FAST_AVG_EN_SET                    BIT(7)

#define VADC_ACCESS                             0xd0
#define VADC_ACCESS_DATA                        0xa5

#define VADC_PERH_RESET_CTL3                    0xda
#define VADC_FOLLOW_WARM_RB                     BIT(2)

#define VADC_DATA                               0x60    /* 16 bits */

#define VADC_CHAN_MIN                   VADC_USBIN
#define VADC_CHAN_MAX                   VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM

/**
 * struct vadc_channel_prop - VADC channel property.
 * @channel: channel number, refer to the channel list.
 * @calibration: calibration type.
 * @decimation: sampling rate supported for the channel.
 * @prescale: channel scaling performed on the input signal.
 * @hw_settle_time: the time between AMUX being configured and the
 *      start of conversion.
 * @avg_samples: ability to provide single result from the ADC
 *      that is an average of multiple measurements.
 * @scale_fn_type: Represents the scaling function to convert voltage
 *      physical units desired by the client for the channel.
 * @channel_name: Channel name used in device tree.
 */
struct vadc_channel_prop {
        unsigned int channel;
        enum vadc_calibration calibration;
        unsigned int decimation;
        unsigned int prescale;
        unsigned int hw_settle_time;
        unsigned int avg_samples;
        enum vadc_scale_fn_type scale_fn_type;
        const char *channel_name;
};

/**
 * struct vadc_priv - VADC private structure.
 * @regmap: pointer to struct regmap.
 * @dev: pointer to struct device.
 * @base: base address for the ADC peripheral.
 * @nchannels: number of VADC channels.
 * @chan_props: array of VADC channel properties.
 * @iio_chans: array of IIO channels specification.
 * @are_ref_measured: are reference points measured.
 * @poll_eoc: use polling instead of interrupt.
 * @complete: VADC result notification after interrupt is received.
 * @graph: store parameters for calibration.
 * @lock: ADC lock for access to the peripheral.
 */
struct vadc_priv {
        struct regmap            *regmap;
        struct device            *dev;
        u16                      base;
        unsigned int             nchannels;
        struct vadc_channel_prop *chan_props;
        struct iio_chan_spec     *iio_chans;
        bool                     are_ref_measured;
        bool                     poll_eoc;
        struct completion        complete;
        struct vadc_linear_graph graph[2];
        struct mutex             lock;
};

static const struct u32_fract vadc_prescale_ratios[] = {
        { .numerator =  1, .denominator =  1 },
        { .numerator =  1, .denominator =  3 },
        { .numerator =  1, .denominator =  4 },
        { .numerator =  1, .denominator =  6 },
        { .numerator =  1, .denominator = 20 },
        { .numerator =  1, .denominator =  8 },
        { .numerator = 10, .denominator = 81 },
        { .numerator =  1, .denominator = 10 },
};

static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
{
        return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
}

static int vadc_write(struct vadc_priv *vadc, u16 offset, u8 data)
{
        return regmap_write(vadc->regmap, vadc->base + offset, data);
}

static int vadc_reset(struct vadc_priv *vadc)
{
        u8 data;
        int ret;

        ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
        if (ret)
                return ret;

        ret = vadc_read(vadc, VADC_PERH_RESET_CTL3, &data);
        if (ret)
                return ret;

        ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
        if (ret)
                return ret;

        data |= VADC_FOLLOW_WARM_RB;

        return vadc_write(vadc, VADC_PERH_RESET_CTL3, data);
}

static int vadc_set_state(struct vadc_priv *vadc, bool state)
{
        return vadc_write(vadc, VADC_EN_CTL1, state ? VADC_EN_CTL1_SET : 0);
}

static void vadc_show_status(struct vadc_priv *vadc)
{
        u8 mode, sta1, chan, dig, en, req;
        int ret;

        ret = vadc_read(vadc, VADC_MODE_CTL, &mode);
        if (ret)
                return;

        ret = vadc_read(vadc, VADC_ADC_DIG_PARAM, &dig);
        if (ret)
                return;

        ret = vadc_read(vadc, VADC_ADC_CH_SEL_CTL, &chan);
        if (ret)
                return;

        ret = vadc_read(vadc, VADC_CONV_REQ, &req);
        if (ret)
                return;

        ret = vadc_read(vadc, VADC_STATUS1, &sta1);
        if (ret)
                return;

        ret = vadc_read(vadc, VADC_EN_CTL1, &en);
        if (ret)
                return;

        dev_err(vadc->dev,
                "mode:%02x en:%02x chan:%02x dig:%02x req:%02x sta1:%02x\n",
                mode, en, chan, dig, req, sta1);
}

static int vadc_configure(struct vadc_priv *vadc,
                          struct vadc_channel_prop *prop)
{
        u8 decimation, mode_ctrl;
        int ret;

        /* Mode selection */
        mode_ctrl = (VADC_OP_MODE_NORMAL << VADC_OP_MODE_SHIFT) |
                     VADC_ADC_TRIM_EN | VADC_AMUX_TRIM_EN;
        ret = vadc_write(vadc, VADC_MODE_CTL, mode_ctrl);
        if (ret)
                return ret;

        /* Channel selection */
        ret = vadc_write(vadc, VADC_ADC_CH_SEL_CTL, prop->channel);
        if (ret)
                return ret;

        /* Digital parameter setup */
        decimation = prop->decimation << VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT;
        ret = vadc_write(vadc, VADC_ADC_DIG_PARAM, decimation);
        if (ret)
                return ret;

        /* HW settle time delay */
        ret = vadc_write(vadc, VADC_HW_SETTLE_DELAY, prop->hw_settle_time);
        if (ret)
                return ret;

        ret = vadc_write(vadc, VADC_FAST_AVG_CTL, prop->avg_samples);
        if (ret)
                return ret;

        if (prop->avg_samples)
                ret = vadc_write(vadc, VADC_FAST_AVG_EN, VADC_FAST_AVG_EN_SET);
        else
                ret = vadc_write(vadc, VADC_FAST_AVG_EN, 0);

        return ret;
}

static int vadc_poll_wait_eoc(struct vadc_priv *vadc, unsigned int interval_us)
{
        unsigned int count, retry;
        u8 sta1;
        int ret;

        retry = interval_us / VADC_CONV_TIME_MIN_US;

        for (count = 0; count < retry; count++) {
                ret = vadc_read(vadc, VADC_STATUS1, &sta1);
                if (ret)
                        return ret;

                sta1 &= VADC_STATUS1_REQ_STS_EOC_MASK;
                if (sta1 == VADC_STATUS1_EOC)
                        return 0;

                usleep_range(VADC_CONV_TIME_MIN_US, VADC_CONV_TIME_MAX_US);
        }

        vadc_show_status(vadc);

        return -ETIMEDOUT;
}

static int vadc_read_result(struct vadc_priv *vadc, u16 *data)
{
        int ret;

        ret = regmap_bulk_read(vadc->regmap, vadc->base + VADC_DATA, data, 2);
        if (ret)
                return ret;

        *data = clamp_t(u16, *data, VADC_MIN_ADC_CODE, VADC_MAX_ADC_CODE);

        return 0;
}

static struct vadc_channel_prop *vadc_get_channel(struct vadc_priv *vadc,
                                                  unsigned int num)
{
        unsigned int i;

        for (i = 0; i < vadc->nchannels; i++)
                if (vadc->chan_props[i].channel == num)
                        return &vadc->chan_props[i];

        dev_dbg(vadc->dev, "no such channel %02x\n", num);

        return NULL;
}

static int vadc_do_conversion(struct vadc_priv *vadc,
                              struct vadc_channel_prop *prop, u16 *data)
{
        unsigned int timeout;
        int ret;

        mutex_lock(&vadc->lock);

        ret = vadc_configure(vadc, prop);
        if (ret)
                goto unlock;

        if (!vadc->poll_eoc)
                reinit_completion(&vadc->complete);

        ret = vadc_set_state(vadc, true);
        if (ret)
                goto unlock;

        ret = vadc_write(vadc, VADC_CONV_REQ, VADC_CONV_REQ_SET);
        if (ret)
                goto err_disable;

        timeout = BIT(prop->avg_samples) * VADC_CONV_TIME_MIN_US * 2;

        if (vadc->poll_eoc) {
                ret = vadc_poll_wait_eoc(vadc, timeout);
        } else {
                ret = wait_for_completion_timeout(&vadc->complete, timeout);
                if (!ret) {
                        ret = -ETIMEDOUT;
                        goto err_disable;
                }

                /* Double check conversion status */
                ret = vadc_poll_wait_eoc(vadc, VADC_CONV_TIME_MIN_US);
                if (ret)
                        goto err_disable;
        }

        ret = vadc_read_result(vadc, data);

err_disable:
        vadc_set_state(vadc, false);
        if (ret)
                dev_err(vadc->dev, "conversion failed\n");
unlock:
        mutex_unlock(&vadc->lock);
        return ret;
}

static int vadc_measure_ref_points(struct vadc_priv *vadc)
{
        struct vadc_channel_prop *prop;
        u16 read_1, read_2;
        int ret;

        vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE;
        vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;

        prop = vadc_get_channel(vadc, VADC_REF_1250MV);
        ret = vadc_do_conversion(vadc, prop, &read_1);
        if (ret)
                goto err;

        /* Try with buffered 625mV channel first */
        prop = vadc_get_channel(vadc, VADC_SPARE1);
        if (!prop)
                prop = vadc_get_channel(vadc, VADC_REF_625MV);

        ret = vadc_do_conversion(vadc, prop, &read_2);
        if (ret)
                goto err;

        if (read_1 == read_2) {
                ret = -EINVAL;
                goto err;
        }

        vadc->graph[VADC_CALIB_ABSOLUTE].dy = read_1 - read_2;
        vadc->graph[VADC_CALIB_ABSOLUTE].gnd = read_2;

        /* Ratiometric calibration */
        prop = vadc_get_channel(vadc, VADC_VDD_VADC);
        ret = vadc_do_conversion(vadc, prop, &read_1);
        if (ret)
                goto err;

        prop = vadc_get_channel(vadc, VADC_GND_REF);
        ret = vadc_do_conversion(vadc, prop, &read_2);
        if (ret)
                goto err;

        if (read_1 == read_2) {
                ret = -EINVAL;
                goto err;
        }

        vadc->graph[VADC_CALIB_RATIOMETRIC].dy = read_1 - read_2;
        vadc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_2;
err:
        if (ret)
                dev_err(vadc->dev, "measure reference points failed\n");

        return ret;
}

static int vadc_prescaling_from_dt(u32 numerator, u32 denominator)
{
        unsigned int pre;

        for (pre = 0; pre < ARRAY_SIZE(vadc_prescale_ratios); pre++)
                if (vadc_prescale_ratios[pre].numerator == numerator &&
                    vadc_prescale_ratios[pre].denominator == denominator)
                        break;

        if (pre == ARRAY_SIZE(vadc_prescale_ratios))
                return -EINVAL;

        return pre;
}

static int vadc_hw_settle_time_from_dt(u32 value)
{
        if ((value <= 1000 && value % 100) || (value > 1000 && value % 2000))
                return -EINVAL;

        if (value <= 1000)
                value /= 100;
        else
                value = value / 2000 + 10;

        return value;
}

static int vadc_avg_samples_from_dt(u32 value)
{
        if (!is_power_of_2(value) || value > VADC_AVG_SAMPLES_MAX)
                return -EINVAL;

        return __ffs64(value);
}

static int vadc_read_raw(struct iio_dev *indio_dev,
                         struct iio_chan_spec const *chan, int *val, int *val2,
                         long mask)
{
        struct vadc_priv *vadc = iio_priv(indio_dev);
        struct vadc_channel_prop *prop;
        u16 adc_code;
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_PROCESSED:
                prop = &vadc->chan_props[chan->address];
                ret = vadc_do_conversion(vadc, prop, &adc_code);
                if (ret)
                        break;

                ret = qcom_vadc_scale(prop->scale_fn_type,
                                &vadc->graph[prop->calibration],
                                &vadc_prescale_ratios[prop->prescale],
                                (prop->calibration == VADC_CALIB_ABSOLUTE),
                                adc_code, val);
                if (ret)
                        break;

                return IIO_VAL_INT;
        case IIO_CHAN_INFO_RAW:
                prop = &vadc->chan_props[chan->address];
                ret = vadc_do_conversion(vadc, prop, &adc_code);
                if (ret)
                        break;

                *val = (int)adc_code;
                return IIO_VAL_INT;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int vadc_fwnode_xlate(struct iio_dev *indio_dev,
                             const struct fwnode_reference_args *iiospec)
{
        struct vadc_priv *vadc = iio_priv(indio_dev);
        unsigned int i;

        for (i = 0; i < vadc->nchannels; i++)
                if (vadc->iio_chans[i].channel == iiospec->args[0])
                        return i;

        return -EINVAL;
}

static int vadc_read_label(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan, char *label)
{
        struct vadc_priv *vadc = iio_priv(indio_dev);
        const char *name = vadc->chan_props[chan->address].channel_name;

        return sysfs_emit(label, "%s\n", name);
}

static const struct iio_info vadc_info = {
        .read_raw = vadc_read_raw,
        .read_label = vadc_read_label,
        .fwnode_xlate = vadc_fwnode_xlate,
};

struct vadc_channels {
        const char *datasheet_name;
        unsigned int prescale_index;
        enum iio_chan_type type;
        long info_mask;
        enum vadc_scale_fn_type scale_fn_type;
};

#define VADC_CHAN(_dname, _type, _mask, _pre, _scale)                   \
        [VADC_##_dname] = {                                             \
                .datasheet_name = __stringify(_dname),                  \
                .prescale_index = _pre,                                 \
                .type = _type,                                          \
                .info_mask = _mask,                                     \
                .scale_fn_type = _scale                                 \
        },                                                              \

#define VADC_NO_CHAN(_dname, _type, _mask, _pre)                        \
        [VADC_##_dname] = {                                             \
                .datasheet_name = __stringify(_dname),                  \
                .prescale_index = _pre,                                 \
                .type = _type,                                          \
                .info_mask = _mask                                      \
        },

#define VADC_CHAN_TEMP(_dname, _pre, _scale)                            \
        VADC_CHAN(_dname, IIO_TEMP,                                     \
                BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED),  \
                _pre, _scale)                                           \

#define VADC_CHAN_VOLT(_dname, _pre, _scale)                            \
        VADC_CHAN(_dname, IIO_VOLTAGE,                                  \
                  BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED),\
                  _pre, _scale)                                         \

#define VADC_CHAN_NO_SCALE(_dname, _pre)                                \
        VADC_NO_CHAN(_dname, IIO_VOLTAGE,                               \
                  BIT(IIO_CHAN_INFO_RAW),                               \
                  _pre)                                                 \

/*
 * The array represents all possible ADC channels found in the supported PMICs.
 * Every index in the array is equal to the channel number per datasheet. The
 * gaps in the array should be treated as reserved channels.
 */
static const struct vadc_channels vadc_chans[] = {
        VADC_CHAN_VOLT(USBIN, 4, SCALE_DEFAULT)
        VADC_CHAN_VOLT(DCIN, 4, SCALE_DEFAULT)
        VADC_CHAN_NO_SCALE(VCHG_SNS, 3)
        VADC_CHAN_NO_SCALE(SPARE1_03, 1)
        VADC_CHAN_NO_SCALE(USB_ID_MV, 1)
        VADC_CHAN_VOLT(VCOIN, 1, SCALE_DEFAULT)
        VADC_CHAN_NO_SCALE(VBAT_SNS, 1)
        VADC_CHAN_VOLT(VSYS, 1, SCALE_DEFAULT)
        VADC_CHAN_TEMP(DIE_TEMP, 0, SCALE_PMIC_THERM)
        VADC_CHAN_VOLT(REF_625MV, 0, SCALE_DEFAULT)
        VADC_CHAN_VOLT(REF_1250MV, 0, SCALE_DEFAULT)
        VADC_CHAN_NO_SCALE(CHG_TEMP, 0)
        VADC_CHAN_NO_SCALE(SPARE1, 0)
        VADC_CHAN_TEMP(SPARE2, 0, SCALE_PMI_CHG_TEMP)
        VADC_CHAN_VOLT(GND_REF, 0, SCALE_DEFAULT)
        VADC_CHAN_VOLT(VDD_VADC, 0, SCALE_DEFAULT)

        VADC_CHAN_NO_SCALE(P_MUX1_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX2_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX3_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX4_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX5_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX6_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX7_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX8_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX9_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX10_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX11_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX12_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX13_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX14_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX15_1_1, 0)
        VADC_CHAN_NO_SCALE(P_MUX16_1_1, 0)

        VADC_CHAN_NO_SCALE(P_MUX1_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX2_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX3_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX4_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX5_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX6_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX7_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX8_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX9_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX10_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX11_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX12_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX13_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX14_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX15_1_3, 1)
        VADC_CHAN_NO_SCALE(P_MUX16_1_3, 1)

        VADC_CHAN_NO_SCALE(LR_MUX1_BAT_THERM, 0)
        VADC_CHAN_VOLT(LR_MUX2_BAT_ID, 0, SCALE_DEFAULT)
        VADC_CHAN_NO_SCALE(LR_MUX3_XO_THERM, 0)
        VADC_CHAN_NO_SCALE(LR_MUX4_AMUX_THM1, 0)
        VADC_CHAN_NO_SCALE(LR_MUX5_AMUX_THM2, 0)
        VADC_CHAN_NO_SCALE(LR_MUX6_AMUX_THM3, 0)
        VADC_CHAN_NO_SCALE(LR_MUX7_HW_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX8_AMUX_THM4, 0)
        VADC_CHAN_NO_SCALE(LR_MUX9_AMUX_THM5, 0)
        VADC_CHAN_NO_SCALE(LR_MUX10_USB_ID, 0)
        VADC_CHAN_NO_SCALE(AMUX_PU1, 0)
        VADC_CHAN_NO_SCALE(AMUX_PU2, 0)
        VADC_CHAN_NO_SCALE(LR_MUX3_BUF_XO_THERM, 0)

        VADC_CHAN_NO_SCALE(LR_MUX1_PU1_BAT_THERM, 0)
        VADC_CHAN_NO_SCALE(LR_MUX2_PU1_BAT_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX3_PU1_XO_THERM, 0)
        VADC_CHAN_TEMP(LR_MUX4_PU1_AMUX_THM1, 0, SCALE_THERM_100K_PULLUP)
        VADC_CHAN_TEMP(LR_MUX5_PU1_AMUX_THM2, 0, SCALE_THERM_100K_PULLUP)
        VADC_CHAN_TEMP(LR_MUX6_PU1_AMUX_THM3, 0, SCALE_THERM_100K_PULLUP)
        VADC_CHAN_NO_SCALE(LR_MUX7_PU1_AMUX_HW_ID, 0)
        VADC_CHAN_TEMP(LR_MUX8_PU1_AMUX_THM4, 0, SCALE_THERM_100K_PULLUP)
        VADC_CHAN_TEMP(LR_MUX9_PU1_AMUX_THM5, 0, SCALE_THERM_100K_PULLUP)
        VADC_CHAN_NO_SCALE(LR_MUX10_PU1_AMUX_USB_ID, 0)
        VADC_CHAN_TEMP(LR_MUX3_BUF_PU1_XO_THERM, 0, SCALE_XOTHERM)

        VADC_CHAN_NO_SCALE(LR_MUX1_PU2_BAT_THERM, 0)
        VADC_CHAN_NO_SCALE(LR_MUX2_PU2_BAT_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX3_PU2_XO_THERM, 0)
        VADC_CHAN_NO_SCALE(LR_MUX4_PU2_AMUX_THM1, 0)
        VADC_CHAN_NO_SCALE(LR_MUX5_PU2_AMUX_THM2, 0)
        VADC_CHAN_NO_SCALE(LR_MUX6_PU2_AMUX_THM3, 0)
        VADC_CHAN_NO_SCALE(LR_MUX7_PU2_AMUX_HW_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX8_PU2_AMUX_THM4, 0)
        VADC_CHAN_NO_SCALE(LR_MUX9_PU2_AMUX_THM5, 0)
        VADC_CHAN_NO_SCALE(LR_MUX10_PU2_AMUX_USB_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX3_BUF_PU2_XO_THERM, 0)

        VADC_CHAN_NO_SCALE(LR_MUX1_PU1_PU2_BAT_THERM, 0)
        VADC_CHAN_NO_SCALE(LR_MUX2_PU1_PU2_BAT_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX3_PU1_PU2_XO_THERM, 0)
        VADC_CHAN_NO_SCALE(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
        VADC_CHAN_NO_SCALE(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
        VADC_CHAN_NO_SCALE(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
        VADC_CHAN_NO_SCALE(LR_MUX7_PU1_PU2_AMUX_HW_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
        VADC_CHAN_NO_SCALE(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
        VADC_CHAN_NO_SCALE(LR_MUX10_PU1_PU2_AMUX_USB_ID, 0)
        VADC_CHAN_NO_SCALE(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
};

static int vadc_get_fw_channel_data(struct device *dev,
                                    struct vadc_channel_prop *prop,
                                    struct fwnode_handle *fwnode)
{
        const char *name = fwnode_get_name(fwnode), *label;
        u32 chan, value, varr[2];
        int ret;

        ret = fwnode_property_read_u32(fwnode, "reg", &chan);
        if (ret) {
                dev_err(dev, "invalid channel number %s\n", name);
                return ret;
        }

        if (chan > VADC_CHAN_MAX || chan < VADC_CHAN_MIN) {
                dev_err(dev, "%s invalid channel number %d\n", name, chan);
                return -EINVAL;
        }

        ret = fwnode_property_read_string(fwnode, "label", &label);
        if (ret)
                label = vadc_chans[chan].datasheet_name;
        prop->channel_name = label;

        /* the channel has DT description */
        prop->channel = chan;

        ret = fwnode_property_read_u32(fwnode, "qcom,decimation", &value);
        if (!ret) {
                ret = qcom_vadc_decimation_from_dt(value);
                if (ret < 0) {
                        dev_err(dev, "%02x invalid decimation %d\n",
                                chan, value);
                        return ret;
                }
                prop->decimation = ret;
        } else {
                prop->decimation = VADC_DEF_DECIMATION;
        }

        ret = fwnode_property_read_u32_array(fwnode, "qcom,pre-scaling", varr, 2);
        if (!ret) {
                ret = vadc_prescaling_from_dt(varr[0], varr[1]);
                if (ret < 0) {
                        dev_err(dev, "%02x invalid pre-scaling <%d %d>\n",
                                chan, varr[0], varr[1]);
                        return ret;
                }
                prop->prescale = ret;
        } else {
                prop->prescale = vadc_chans[prop->channel].prescale_index;
        }

        ret = fwnode_property_read_u32(fwnode, "qcom,hw-settle-time", &value);
        if (!ret) {
                ret = vadc_hw_settle_time_from_dt(value);
                if (ret < 0) {
                        dev_err(dev, "%02x invalid hw-settle-time %d us\n",
                                chan, value);
                        return ret;
                }
                prop->hw_settle_time = ret;
        } else {
                prop->hw_settle_time = VADC_DEF_HW_SETTLE_TIME;
        }

        ret = fwnode_property_read_u32(fwnode, "qcom,avg-samples", &value);
        if (!ret) {
                ret = vadc_avg_samples_from_dt(value);
                if (ret < 0) {
                        dev_err(dev, "%02x invalid avg-samples %d\n",
                                chan, value);
                        return ret;
                }
                prop->avg_samples = ret;
        } else {
                prop->avg_samples = VADC_DEF_AVG_SAMPLES;
        }

        if (fwnode_property_read_bool(fwnode, "qcom,ratiometric"))
                prop->calibration = VADC_CALIB_RATIOMETRIC;
        else
                prop->calibration = VADC_CALIB_ABSOLUTE;

        dev_dbg(dev, "%02x name %s\n", chan, name);

        return 0;
}

static int vadc_get_fw_data(struct vadc_priv *vadc)
{
        const struct vadc_channels *vadc_chan;
        struct iio_chan_spec *iio_chan;
        struct vadc_channel_prop prop;
        unsigned int index = 0;
        int ret;

        vadc->nchannels = device_get_child_node_count(vadc->dev);
        if (!vadc->nchannels)
                return -EINVAL;

        vadc->iio_chans = devm_kcalloc(vadc->dev, vadc->nchannels,
                                       sizeof(*vadc->iio_chans), GFP_KERNEL);
        if (!vadc->iio_chans)
                return -ENOMEM;

        vadc->chan_props = devm_kcalloc(vadc->dev, vadc->nchannels,
                                        sizeof(*vadc->chan_props), GFP_KERNEL);
        if (!vadc->chan_props)
                return -ENOMEM;

        iio_chan = vadc->iio_chans;

        device_for_each_child_node_scoped(vadc->dev, child) {
                ret = vadc_get_fw_channel_data(vadc->dev, &prop, child);
                if (ret)
                        return ret;

                prop.scale_fn_type = vadc_chans[prop.channel].scale_fn_type;
                vadc->chan_props[index] = prop;

                vadc_chan = &vadc_chans[prop.channel];

                iio_chan->channel = prop.channel;
                iio_chan->datasheet_name = vadc_chan->datasheet_name;
                iio_chan->info_mask_separate = vadc_chan->info_mask;
                iio_chan->type = vadc_chan->type;
                iio_chan->indexed = 1;
                iio_chan->address = index++;

                iio_chan++;
        }

        /* These channels are mandatory, they are used as reference points */
        if (!vadc_get_channel(vadc, VADC_REF_1250MV)) {
                dev_err(vadc->dev, "Please define 1.25V channel\n");
                return -ENODEV;
        }

        if (!vadc_get_channel(vadc, VADC_REF_625MV)) {
                dev_err(vadc->dev, "Please define 0.625V channel\n");
                return -ENODEV;
        }

        if (!vadc_get_channel(vadc, VADC_VDD_VADC)) {
                dev_err(vadc->dev, "Please define VDD channel\n");
                return -ENODEV;
        }

        if (!vadc_get_channel(vadc, VADC_GND_REF)) {
                dev_err(vadc->dev, "Please define GND channel\n");
                return -ENODEV;
        }

        return 0;
}

static irqreturn_t vadc_isr(int irq, void *dev_id)
{
        struct vadc_priv *vadc = dev_id;

        complete(&vadc->complete);

        return IRQ_HANDLED;
}

static int vadc_check_revision(struct vadc_priv *vadc)
{
        u8 val;
        int ret;

        ret = vadc_read(vadc, VADC_PERPH_TYPE, &val);
        if (ret)
                return ret;

        if (val < VADC_PERPH_TYPE_ADC) {
                dev_err(vadc->dev, "%d is not ADC\n", val);
                return -ENODEV;
        }

        ret = vadc_read(vadc, VADC_PERPH_SUBTYPE, &val);
        if (ret)
                return ret;

        if (val < VADC_PERPH_SUBTYPE_VADC) {
                dev_err(vadc->dev, "%d is not VADC\n", val);
                return -ENODEV;
        }

        ret = vadc_read(vadc, VADC_REVISION2, &val);
        if (ret)
                return ret;

        if (val < VADC_REVISION2_SUPPORTED_VADC) {
                dev_err(vadc->dev, "revision %d not supported\n", val);
                return -ENODEV;
        }

        return 0;
}

static int vadc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct iio_dev *indio_dev;
        struct vadc_priv *vadc;
        struct regmap *regmap;
        int ret, irq_eoc;
        u32 reg;

        regmap = dev_get_regmap(dev->parent, NULL);
        if (!regmap)
                return -ENODEV;

        ret = device_property_read_u32(dev, "reg", &reg);
        if (ret < 0)
                return ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*vadc));
        if (!indio_dev)
                return -ENOMEM;

        vadc = iio_priv(indio_dev);
        vadc->regmap = regmap;
        vadc->dev = dev;
        vadc->base = reg;
        vadc->are_ref_measured = false;
        init_completion(&vadc->complete);
        mutex_init(&vadc->lock);

        ret = vadc_check_revision(vadc);
        if (ret)
                return ret;

        ret = vadc_get_fw_data(vadc);
        if (ret)
                return ret;

        irq_eoc = platform_get_irq(pdev, 0);
        if (irq_eoc < 0) {
                if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
                        return irq_eoc;
                vadc->poll_eoc = true;
        } else {
                ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
                                       "spmi-vadc", vadc);
                if (ret)
                        return ret;
        }

        ret = vadc_reset(vadc);
        if (ret) {
                dev_err(dev, "reset failed\n");
                return ret;
        }

        ret = vadc_measure_ref_points(vadc);
        if (ret)
                return ret;

        indio_dev->name = pdev->name;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &vadc_info;
        indio_dev->channels = vadc->iio_chans;
        indio_dev->num_channels = vadc->nchannels;

        return devm_iio_device_register(dev, indio_dev);
}

static const struct of_device_id vadc_match_table[] = {
        { .compatible = "qcom,spmi-vadc" },
        { }
};
MODULE_DEVICE_TABLE(of, vadc_match_table);

static struct platform_driver vadc_driver = {
        .driver = {
                   .name = "qcom-spmi-vadc",
                   .of_match_table = vadc_match_table,
        },
        .probe = vadc_probe,
};
module_platform_driver(vadc_driver);

MODULE_ALIAS("platform:qcom-spmi-vadc");
MODULE_DESCRIPTION("Qualcomm SPMI PMIC voltage ADC driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Stanimir Varbanov <svarbanov@mm-sol.com>");
MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>");