/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Support code for Analog Devices Sigma-Delta ADCs
 *
 * Copyright 2012 Analog Devices Inc.
 *  Author: Lars-Peter Clausen <lars@metafoo.de>
 */
#ifndef __AD_SIGMA_DELTA_H__
#define __AD_SIGMA_DELTA_H__

#include <linux/iio/iio.h>

enum ad_sigma_delta_mode {
        AD_SD_MODE_CONTINUOUS = 0,
        AD_SD_MODE_SINGLE = 1,
        AD_SD_MODE_IDLE = 2,
        AD_SD_MODE_POWERDOWN = 3,
};

/**
 * struct ad_sigma_delta_calib_data - Calibration data for Sigma Delta devices
 * @mode: Calibration mode.
 * @channel: Calibration channel.
 */
struct ad_sd_calib_data {
        unsigned int mode;
        unsigned int channel;
};

struct ad_sigma_delta;
struct device;
struct gpio_desc;
struct iio_dev;
struct spi_offload;
struct spi_offload_trigger;

/**
 * struct ad_sigma_delta_info - Sigma Delta driver specific callbacks and options
 * @set_channel: Will be called to select the current channel, may be NULL.
 * @append_status: Will be called to enable status append at the end of the sample, may be NULL.
 * @set_mode: Will be called to select the current mode, may be NULL.
 * @disable_all: Will be called to disable all channels, may be NULL.
 * @disable_one: Will be called to disable a single channel after
 *              ad_sigma_delta_single_conversion(), may be NULL.
 *              Usage of this callback expects iio_chan_spec.address to contain
 *              the value required for the driver to identify the channel.
 * @postprocess_sample: Is called for each sampled data word, can be used to
 *              modify or drop the sample data, it, may be NULL.
 * @has_registers: true if the device has writable and readable registers, false
 *              if there is just one read-only sample data shift register.
 * @has_named_irqs: Set to true if there is more than one IRQ line.
 * @supports_spi_offload: Set to true if the driver supports SPI offload. Often
 *              special considerations are needed for scan_type and other channel
 *              info, so individual drivers have to set this to let the core
 *              code know that it can use SPI offload if it is available.
 * @addr_shift: Shift of the register address in the communications register.
 * @read_mask: Mask for the communications register having the read bit set.
 * @status_ch_mask: Mask for the channel number stored in status register.
 * @data_reg: Address of the data register, if 0 the default address of 0x3 will
 *   be used.
 * @irq_flags: flags for the interrupt used by the triggered buffer
 * @num_slots: Number of sequencer slots
 * @num_resetclks: Number of SPI clk cycles with MOSI=1 to reset the chip.
 */
struct ad_sigma_delta_info {
        int (*set_channel)(struct ad_sigma_delta *, unsigned int channel);
        int (*append_status)(struct ad_sigma_delta *, bool append);
        int (*set_mode)(struct ad_sigma_delta *, enum ad_sigma_delta_mode mode);
        int (*disable_all)(struct ad_sigma_delta *);
        int (*disable_one)(struct ad_sigma_delta *, unsigned int chan);
        int (*postprocess_sample)(struct ad_sigma_delta *, unsigned int raw_sample);
        bool has_registers;
        bool has_named_irqs;
        bool supports_spi_offload;
        unsigned int addr_shift;
        unsigned int read_mask;
        unsigned int status_ch_mask;
        unsigned int data_reg;
        unsigned long irq_flags;
        unsigned int num_slots;
        unsigned int num_resetclks;
};

/**
 * struct ad_sigma_delta - Sigma Delta device struct
 * @spi: The spi device associated with the Sigma Delta device.
 * @trig: The IIO trigger associated with the Sigma Delta device.
 *
 * Most of the fields are private to the sigma delta library code and should not
 * be accessed by individual drivers.
 */
struct ad_sigma_delta {
        struct spi_device       *spi;
        struct iio_trigger      *trig;

/* private: */
        struct completion       completion;
        spinlock_t              irq_lock; /* protects .irq_dis and irq en/disable state */
        bool                    irq_dis;

        bool                    bus_locked;
        bool                    keep_cs_asserted;

        u8                      comm;

        const struct ad_sigma_delta_info *info;
        unsigned int            active_slots;
        unsigned int            current_slot;
        unsigned int            num_slots;
        struct gpio_desc        *rdy_gpiod;
        int                     irq_line;
        bool                    status_appended;
        /* map slots to channels in order to know what to expect from devices */
        unsigned int            *slots;
        struct spi_message      sample_msg;
        struct spi_transfer     sample_xfer[2];
        u8                      *samples_buf;
        struct spi_offload      *offload;
        struct spi_offload_trigger *offload_trigger;

        /*
         * DMA (thus cache coherency maintenance) requires the
         * transfer buffers to live in their own cache lines.
         * 'tx_buf' is up to 32 bits.
         * 'rx_buf' is up to 32 bits per sample + 64 bit timestamp,
         * rounded to 16 bytes to take into account padding.
         */
        u8                              tx_buf[4] __aligned(IIO_DMA_MINALIGN);
        u8                              rx_buf[16] __aligned(8);
        u8                              sample_addr;
};

static inline bool ad_sigma_delta_has_spi_offload(struct ad_sigma_delta *sd)
{
        return sd->offload != NULL;
}

static inline int ad_sigma_delta_set_channel(struct ad_sigma_delta *sd,
        unsigned int channel)
{
        if (sd->info->set_channel)
                return sd->info->set_channel(sd, channel);

        return 0;
}

static inline int ad_sigma_delta_append_status(struct ad_sigma_delta *sd, bool append)
{
        int ret;

        if (sd->info->append_status) {
                ret = sd->info->append_status(sd, append);
                if (ret < 0)
                        return ret;

                sd->status_appended = append;
        }

        return 0;
}

static inline int ad_sigma_delta_disable_all(struct ad_sigma_delta *sd)
{
        if (sd->info->disable_all)
                return sd->info->disable_all(sd);

        return 0;
}

static inline int ad_sigma_delta_disable_one(struct ad_sigma_delta *sd,
                                             unsigned int chan)
{
        if (sd->info->disable_one)
                return sd->info->disable_one(sd, chan);

        return 0;
}

static inline int ad_sigma_delta_set_mode(struct ad_sigma_delta *sd,
        unsigned int mode)
{
        if (sd->info->set_mode)
                return sd->info->set_mode(sd, mode);

        return 0;
}

static inline int ad_sigma_delta_postprocess_sample(struct ad_sigma_delta *sd,
        unsigned int raw_sample)
{
        if (sd->info->postprocess_sample)
                return sd->info->postprocess_sample(sd, raw_sample);

        return 0;
}

void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, u8 comm);
int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
        unsigned int size, unsigned int val);
int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
        unsigned int size, unsigned int *val);

int ad_sd_reset(struct ad_sigma_delta *sigma_delta);

int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, int *val);
int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
        unsigned int mode, unsigned int channel);
int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
        const struct ad_sd_calib_data *cd, unsigned int n);
int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
        struct spi_device *spi, const struct ad_sigma_delta_info *info);

int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev);

int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig);

#endif