// SPDX-License-Identifier: GPL-2.0+
/*
 * ADXL372 3-Axis Digital Accelerometer core driver
 *
 * Copyright 2018 Analog Devices Inc.
 */

#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/events.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include "adxl372.h"

/* ADXL372 registers definition */
#define ADXL372_DEVID                   0x00
#define ADXL372_DEVID_MST               0x01
#define ADXL372_PARTID                  0x02
#define ADXL372_STATUS_1                0x04
#define ADXL372_STATUS_2                0x05
#define ADXL372_FIFO_ENTRIES_2          0x06
#define ADXL372_FIFO_ENTRIES_1          0x07
#define ADXL372_X_DATA_H                0x08
#define ADXL372_X_DATA_L                0x09
#define ADXL372_Y_DATA_H                0x0A
#define ADXL372_Y_DATA_L                0x0B
#define ADXL372_Z_DATA_H                0x0C
#define ADXL372_Z_DATA_L                0x0D
#define ADXL372_X_MAXPEAK_H             0x15
#define ADXL372_X_MAXPEAK_L             0x16
#define ADXL372_Y_MAXPEAK_H             0x17
#define ADXL372_Y_MAXPEAK_L             0x18
#define ADXL372_Z_MAXPEAK_H             0x19
#define ADXL372_Z_MAXPEAK_L             0x1A
#define ADXL372_OFFSET_X                0x20
#define ADXL372_OFFSET_Y                0x21
#define ADXL372_OFFSET_Z                0x22
#define ADXL372_X_THRESH_ACT_H          0x23
#define ADXL372_X_THRESH_ACT_L          0x24
#define ADXL372_Y_THRESH_ACT_H          0x25
#define ADXL372_Y_THRESH_ACT_L          0x26
#define ADXL372_Z_THRESH_ACT_H          0x27
#define ADXL372_Z_THRESH_ACT_L          0x28
#define ADXL372_TIME_ACT                0x29
#define ADXL372_X_THRESH_INACT_H        0x2A
#define ADXL372_X_THRESH_INACT_L        0x2B
#define ADXL372_Y_THRESH_INACT_H        0x2C
#define ADXL372_Y_THRESH_INACT_L        0x2D
#define ADXL372_Z_THRESH_INACT_H        0x2E
#define ADXL372_Z_THRESH_INACT_L        0x2F
#define ADXL372_TIME_INACT_H            0x30
#define ADXL372_TIME_INACT_L            0x31
#define ADXL372_X_THRESH_ACT2_H         0x32
#define ADXL372_X_THRESH_ACT2_L         0x33
#define ADXL372_Y_THRESH_ACT2_H         0x34
#define ADXL372_Y_THRESH_ACT2_L         0x35
#define ADXL372_Z_THRESH_ACT2_H         0x36
#define ADXL372_Z_THRESH_ACT2_L         0x37
#define ADXL372_HPF                     0x38
#define ADXL372_FIFO_SAMPLES            0x39
#define ADXL372_FIFO_CTL                0x3A
#define ADXL372_INT1_MAP                0x3B
#define ADXL372_INT2_MAP                0x3C
#define ADXL372_TIMING                  0x3D
#define ADXL372_MEASURE                 0x3E
#define ADXL372_POWER_CTL               0x3F
#define ADXL372_SELF_TEST               0x40
#define ADXL372_RESET                   0x41
#define ADXL372_FIFO_DATA               0x42

#define ADXL372_DEVID_VAL               0xAD
#define ADXL372_PARTID_VAL              0xFA
#define ADXL372_RESET_CODE              0x52

/* ADXL372_POWER_CTL */
#define ADXL372_POWER_CTL_MODE_MSK              GENMASK_ULL(1, 0)
#define ADXL372_POWER_CTL_MODE(x)               (((x) & 0x3) << 0)

/* ADXL372_MEASURE */
#define ADXL372_MEASURE_LINKLOOP_MSK            GENMASK_ULL(5, 4)
#define ADXL372_MEASURE_LINKLOOP_MODE(x)        (((x) & 0x3) << 4)
#define ADXL372_MEASURE_BANDWIDTH_MSK           GENMASK_ULL(2, 0)
#define ADXL372_MEASURE_BANDWIDTH_MODE(x)       (((x) & 0x7) << 0)

/* ADXL372_TIMING */
#define ADXL372_TIMING_ODR_MSK                  GENMASK_ULL(7, 5)
#define ADXL372_TIMING_ODR_MODE(x)              (((x) & 0x7) << 5)

/* ADXL372_FIFO_CTL */
#define ADXL372_FIFO_CTL_FORMAT_MSK             GENMASK(5, 3)
#define ADXL372_FIFO_CTL_FORMAT_MODE(x)         (((x) & 0x7) << 3)
#define ADXL372_FIFO_CTL_MODE_MSK               GENMASK(2, 1)
#define ADXL372_FIFO_CTL_MODE_MODE(x)           (((x) & 0x3) << 1)
#define ADXL372_FIFO_CTL_SAMPLES_MSK            BIT(1)
#define ADXL372_FIFO_CTL_SAMPLES_MODE(x)        (((x) > 0xFF) ? 1 : 0)

/* ADXL372_STATUS_1 */
#define ADXL372_STATUS_1_DATA_RDY(x)            (((x) >> 0) & 0x1)
#define ADXL372_STATUS_1_FIFO_RDY(x)            (((x) >> 1) & 0x1)
#define ADXL372_STATUS_1_FIFO_FULL(x)           (((x) >> 2) & 0x1)
#define ADXL372_STATUS_1_FIFO_OVR(x)            (((x) >> 3) & 0x1)
#define ADXL372_STATUS_1_USR_NVM_BUSY(x)        (((x) >> 5) & 0x1)
#define ADXL372_STATUS_1_AWAKE(x)               (((x) >> 6) & 0x1)
#define ADXL372_STATUS_1_ERR_USR_REGS(x)        (((x) >> 7) & 0x1)

/* ADXL372_INT1_MAP */
#define ADXL372_INT1_MAP_DATA_RDY_MSK           BIT(0)
#define ADXL372_INT1_MAP_DATA_RDY_MODE(x)       (((x) & 0x1) << 0)
#define ADXL372_INT1_MAP_FIFO_RDY_MSK           BIT(1)
#define ADXL372_INT1_MAP_FIFO_RDY_MODE(x)       (((x) & 0x1) << 1)
#define ADXL372_INT1_MAP_FIFO_FULL_MSK          BIT(2)
#define ADXL372_INT1_MAP_FIFO_FULL_MODE(x)      (((x) & 0x1) << 2)
#define ADXL372_INT1_MAP_FIFO_OVR_MSK           BIT(3)
#define ADXL372_INT1_MAP_FIFO_OVR_MODE(x)       (((x) & 0x1) << 3)
#define ADXL372_INT1_MAP_INACT_MSK              BIT(4)
#define ADXL372_INT1_MAP_INACT_MODE(x)          (((x) & 0x1) << 4)
#define ADXL372_INT1_MAP_ACT_MSK                BIT(5)
#define ADXL372_INT1_MAP_ACT_MODE(x)            (((x) & 0x1) << 5)
#define ADXL372_INT1_MAP_AWAKE_MSK              BIT(6)
#define ADXL372_INT1_MAP_AWAKE_MODE(x)          (((x) & 0x1) << 6)
#define ADXL372_INT1_MAP_LOW_MSK                BIT(7)
#define ADXL372_INT1_MAP_LOW_MODE(x)            (((x) & 0x1) << 7)

/* The ADXL372 includes a deep, 512 sample FIFO buffer */
#define ADXL372_FIFO_SIZE                       512

/*
 * At +/- 200g with 12-bit resolution, scale is computed as:
 * (200 + 200) * 9.81 / (2^12 - 1) = 0.958241
 */
#define ADXL372_USCALE  958241

enum adxl372_op_mode {
        ADXL372_STANDBY,
        ADXL372_WAKE_UP,
        ADXL372_INSTANT_ON,
        ADXL372_FULL_BW_MEASUREMENT,
};

enum adxl372_act_proc_mode {
        ADXL372_DEFAULT,
        ADXL372_LINKED,
        ADXL372_LOOPED,
};

enum adxl372_th_activity {
        ADXL372_ACTIVITY,
        ADXL372_ACTIVITY2,
        ADXL372_INACTIVITY,
};

enum adxl372_odr {
        ADXL372_ODR_400HZ,
        ADXL372_ODR_800HZ,
        ADXL372_ODR_1600HZ,
        ADXL372_ODR_3200HZ,
        ADXL372_ODR_6400HZ,
};

enum adxl372_bandwidth {
        ADXL372_BW_200HZ,
        ADXL372_BW_400HZ,
        ADXL372_BW_800HZ,
        ADXL372_BW_1600HZ,
        ADXL372_BW_3200HZ,
};

static const unsigned int adxl372_th_reg_high_addr[3] = {
        [ADXL372_ACTIVITY] = ADXL372_X_THRESH_ACT_H,
        [ADXL372_ACTIVITY2] = ADXL372_X_THRESH_ACT2_H,
        [ADXL372_INACTIVITY] = ADXL372_X_THRESH_INACT_H,
};

enum adxl372_fifo_format {
        ADXL372_XYZ_FIFO,
        ADXL372_X_FIFO,
        ADXL372_Y_FIFO,
        ADXL372_XY_FIFO,
        ADXL372_Z_FIFO,
        ADXL372_XZ_FIFO,
        ADXL372_YZ_FIFO,
        ADXL372_XYZ_PEAK_FIFO,
};

enum adxl372_fifo_mode {
        ADXL372_FIFO_BYPASSED,
        ADXL372_FIFO_STREAMED,
        ADXL372_FIFO_TRIGGERED,
        ADXL372_FIFO_OLD_SAVED
};

static const int adxl372_samp_freq_tbl[5] = {
        400, 800, 1600, 3200, 6400,
};

static const int adxl372_bw_freq_tbl[5] = {
        200, 400, 800, 1600, 3200,
};

struct adxl372_axis_lookup {
        unsigned int bits;
        enum adxl372_fifo_format fifo_format;
};

static const struct adxl372_axis_lookup adxl372_axis_lookup_table[] = {
        { BIT(0), ADXL372_X_FIFO },
        { BIT(1), ADXL372_Y_FIFO },
        { BIT(2), ADXL372_Z_FIFO },
        { BIT(0) | BIT(1), ADXL372_XY_FIFO },
        { BIT(0) | BIT(2), ADXL372_XZ_FIFO },
        { BIT(1) | BIT(2), ADXL372_YZ_FIFO },
        { BIT(0) | BIT(1) | BIT(2), ADXL372_XYZ_FIFO },
};

#define ADXL372_ACCEL_CHANNEL(index, reg, axis) {                       \
        .type = IIO_ACCEL,                                              \
        .address = reg,                                                 \
        .modified = 1,                                                  \
        .channel2 = IIO_MOD_##axis,                                     \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |          \
                                    BIT(IIO_CHAN_INFO_SAMP_FREQ) |      \
                BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),       \
        .scan_index = index,                                            \
        .scan_type = {                                                  \
                .sign = 's',                                            \
                .realbits = 12,                                         \
                .storagebits = 16,                                      \
                .shift = 4,                                             \
        },                                                              \
}

static const struct iio_chan_spec adxl372_channels[] = {
        ADXL372_ACCEL_CHANNEL(0, ADXL372_X_DATA_H, X),
        ADXL372_ACCEL_CHANNEL(1, ADXL372_Y_DATA_H, Y),
        ADXL372_ACCEL_CHANNEL(2, ADXL372_Z_DATA_H, Z),
};

struct adxl372_state {
        int                             irq;
        struct device                   *dev;
        struct regmap                   *regmap;
        struct iio_trigger              *dready_trig;
        enum adxl372_fifo_mode          fifo_mode;
        enum adxl372_fifo_format        fifo_format;
        enum adxl372_op_mode            op_mode;
        enum adxl372_act_proc_mode      act_proc_mode;
        enum adxl372_odr                odr;
        enum adxl372_bandwidth          bw;
        u32                             act_time_ms;
        u32                             inact_time_ms;
        u8                              fifo_set_size;
        u8                              int1_bitmask;
        u8                              int2_bitmask;
        u16                             watermark;
        __be16                          fifo_buf[ADXL372_FIFO_SIZE];
};

static const unsigned long adxl372_channel_masks[] = {
        BIT(0), BIT(1), BIT(2),
        BIT(0) | BIT(1),
        BIT(0) | BIT(2),
        BIT(1) | BIT(2),
        BIT(0) | BIT(1) | BIT(2),
        0
};

static int adxl372_read_axis(struct adxl372_state *st, u8 addr)
{
        __be16 regval;
        int ret;

        ret = regmap_bulk_read(st->regmap, addr, &regval, sizeof(regval));
        if (ret < 0)
                return ret;

        return be16_to_cpu(regval);
}

static int adxl372_set_op_mode(struct adxl372_state *st,
                               enum adxl372_op_mode op_mode)
{
        int ret;

        ret = regmap_update_bits(st->regmap, ADXL372_POWER_CTL,
                                 ADXL372_POWER_CTL_MODE_MSK,
                                 ADXL372_POWER_CTL_MODE(op_mode));
        if (ret < 0)
                return ret;

        st->op_mode = op_mode;

        return ret;
}

static int adxl372_set_odr(struct adxl372_state *st,
                           enum adxl372_odr odr)
{
        int ret;

        ret = regmap_update_bits(st->regmap, ADXL372_TIMING,
                                 ADXL372_TIMING_ODR_MSK,
                                 ADXL372_TIMING_ODR_MODE(odr));
        if (ret < 0)
                return ret;

        st->odr = odr;

        return ret;
}

static int adxl372_find_closest_match(const int *array,
                                      unsigned int size, int val)
{
        int i;

        for (i = 0; i < size; i++) {
                if (val <= array[i])
                        return i;
        }

        return size - 1;
}

static int adxl372_set_bandwidth(struct adxl372_state *st,
                                 enum adxl372_bandwidth bw)
{
        int ret;

        ret = regmap_update_bits(st->regmap, ADXL372_MEASURE,
                                 ADXL372_MEASURE_BANDWIDTH_MSK,
                                 ADXL372_MEASURE_BANDWIDTH_MODE(bw));
        if (ret < 0)
                return ret;

        st->bw = bw;

        return ret;
}

static int adxl372_set_act_proc_mode(struct adxl372_state *st,
                                     enum adxl372_act_proc_mode mode)
{
        int ret;

        ret = regmap_update_bits(st->regmap,
                                 ADXL372_MEASURE,
                                 ADXL372_MEASURE_LINKLOOP_MSK,
                                 ADXL372_MEASURE_LINKLOOP_MODE(mode));
        if (ret < 0)
                return ret;

        st->act_proc_mode = mode;

        return ret;
}

static int adxl372_set_activity_threshold(struct adxl372_state *st,
                                          enum adxl372_th_activity act,
                                          bool ref_en, bool enable,
                                          unsigned int threshold)
{
        unsigned char buf[6];
        unsigned char th_reg_high_val, th_reg_low_val, th_reg_high_addr;

        /* scale factor is 100 mg/code */
        th_reg_high_val = (threshold / 100) >> 3;
        th_reg_low_val = ((threshold / 100) << 5) | (ref_en << 1) | enable;
        th_reg_high_addr = adxl372_th_reg_high_addr[act];

        buf[0] = th_reg_high_val;
        buf[1] = th_reg_low_val;
        buf[2] = th_reg_high_val;
        buf[3] = th_reg_low_val;
        buf[4] = th_reg_high_val;
        buf[5] = th_reg_low_val;

        return regmap_bulk_write(st->regmap, th_reg_high_addr,
                                 buf, ARRAY_SIZE(buf));
}

static int adxl372_set_activity_time_ms(struct adxl372_state *st,
                                        unsigned int act_time_ms)
{
        unsigned int reg_val, scale_factor;
        int ret;

        /*
         * 3.3 ms per code is the scale factor of the TIME_ACT register for
         * ODR = 6400 Hz. It is 6.6 ms per code for ODR = 3200 Hz and below.
         */
        if (st->odr == ADXL372_ODR_6400HZ)
                scale_factor = 3300;
        else
                scale_factor = 6600;

        reg_val = DIV_ROUND_CLOSEST(act_time_ms * 1000, scale_factor);

        /* TIME_ACT register is 8 bits wide */
        if (reg_val > 0xFF)
                reg_val = 0xFF;

        ret = regmap_write(st->regmap, ADXL372_TIME_ACT, reg_val);
        if (ret < 0)
                return ret;

        st->act_time_ms = act_time_ms;

        return ret;
}

static int adxl372_set_inactivity_time_ms(struct adxl372_state *st,
                                          unsigned int inact_time_ms)
{
        unsigned int reg_val_h, reg_val_l, res, scale_factor;
        int ret;

        /*
         * 13 ms per code is the scale factor of the TIME_INACT register for
         * ODR = 6400 Hz. It is 26 ms per code for ODR = 3200 Hz and below.
         */
        if (st->odr == ADXL372_ODR_6400HZ)
                scale_factor = 13;
        else
                scale_factor = 26;

        res = DIV_ROUND_CLOSEST(inact_time_ms, scale_factor);
        reg_val_h = (res >> 8) & 0xFF;
        reg_val_l = res & 0xFF;

        ret = regmap_write(st->regmap, ADXL372_TIME_INACT_H, reg_val_h);
        if (ret < 0)
                return ret;

        ret = regmap_write(st->regmap, ADXL372_TIME_INACT_L, reg_val_l);
        if (ret < 0)
                return ret;

        st->inact_time_ms = inact_time_ms;

        return ret;
}

static int adxl372_set_interrupts(struct adxl372_state *st,
                                  unsigned char int1_bitmask,
                                  unsigned char int2_bitmask)
{
        int ret;

        ret = regmap_write(st->regmap, ADXL372_INT1_MAP, int1_bitmask);
        if (ret < 0)
                return ret;

        return regmap_write(st->regmap, ADXL372_INT2_MAP, int2_bitmask);
}

static int adxl372_configure_fifo(struct adxl372_state *st)
{
        unsigned int fifo_samples, fifo_ctl;
        int ret;

        /* FIFO must be configured while in standby mode */
        ret = adxl372_set_op_mode(st, ADXL372_STANDBY);
        if (ret < 0)
                return ret;

        /*
         * watermark stores the number of sets; we need to write the FIFO
         * registers with the number of samples
         */
        fifo_samples = (st->watermark * st->fifo_set_size);
        fifo_ctl = ADXL372_FIFO_CTL_FORMAT_MODE(st->fifo_format) |
                   ADXL372_FIFO_CTL_MODE_MODE(st->fifo_mode) |
                   ADXL372_FIFO_CTL_SAMPLES_MODE(fifo_samples);

        ret = regmap_write(st->regmap,
                           ADXL372_FIFO_SAMPLES, fifo_samples & 0xFF);
        if (ret < 0)
                return ret;

        ret = regmap_write(st->regmap, ADXL372_FIFO_CTL, fifo_ctl);
        if (ret < 0)
                return ret;

        return adxl372_set_op_mode(st, ADXL372_FULL_BW_MEASUREMENT);
}

static int adxl372_get_status(struct adxl372_state *st,
                              u8 *status1, u8 *status2,
                              u16 *fifo_entries)
{
        __be32 buf;
        u32 val;
        int ret;

        /* STATUS1, STATUS2, FIFO_ENTRIES2 and FIFO_ENTRIES are adjacent regs */
        ret = regmap_bulk_read(st->regmap, ADXL372_STATUS_1,
                               &buf, sizeof(buf));
        if (ret < 0)
                return ret;

        val = be32_to_cpu(buf);

        *status1 = (val >> 24) & 0x0F;
        *status2 = (val >> 16) & 0x0F;
        /*
         * FIFO_ENTRIES contains the least significant byte, and FIFO_ENTRIES2
         * contains the two most significant bits
         */
        *fifo_entries = val & 0x3FF;

        return ret;
}

static irqreturn_t adxl372_trigger_handler(int irq, void  *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct adxl372_state *st = iio_priv(indio_dev);
        u8 status1, status2;
        u16 fifo_entries;
        int i, ret;

        ret = adxl372_get_status(st, &status1, &status2, &fifo_entries);
        if (ret < 0)
                goto err;

        if (st->fifo_mode != ADXL372_FIFO_BYPASSED &&
            ADXL372_STATUS_1_FIFO_FULL(status1)) {
                /*
                 * When reading data from multiple axes from the FIFO,
                 * to ensure that data is not overwritten and stored out
                 * of order at least one sample set must be left in the
                 * FIFO after every read.
                 */
                fifo_entries -= st->fifo_set_size;

                /* Read data from the FIFO */
                ret = regmap_noinc_read(st->regmap, ADXL372_FIFO_DATA,
                                        st->fifo_buf,
                                        fifo_entries * sizeof(u16));
                if (ret < 0)
                        goto err;

                /* Each sample is 2 bytes */
                for (i = 0; i < fifo_entries; i += st->fifo_set_size)
                        iio_push_to_buffers(indio_dev, &st->fifo_buf[i]);
        }
err:
        iio_trigger_notify_done(indio_dev->trig);
        return IRQ_HANDLED;
}

static int adxl372_setup(struct adxl372_state *st)
{
        unsigned int regval;
        int ret;

        ret = regmap_read(st->regmap, ADXL372_DEVID, &regval);
        if (ret < 0)
                return ret;

        if (regval != ADXL372_DEVID_VAL) {
                dev_err(st->dev, "Invalid chip id %x\n", regval);
                return -ENODEV;
        }

        /*
         * Perform a software reset to make sure the device is in a consistent
         * state after start up.
         */
        ret = regmap_write(st->regmap, ADXL372_RESET, ADXL372_RESET_CODE);
        if (ret < 0)
                return ret;

        ret = adxl372_set_op_mode(st, ADXL372_STANDBY);
        if (ret < 0)
                return ret;

        /* Set threshold for activity detection to 1g */
        ret = adxl372_set_activity_threshold(st, ADXL372_ACTIVITY,
                                             true, true, 1000);
        if (ret < 0)
                return ret;

        /* Set threshold for inactivity detection to 100mg */
        ret = adxl372_set_activity_threshold(st, ADXL372_INACTIVITY,
                                             true, true, 100);
        if (ret < 0)
                return ret;

        /* Set activity processing in Looped mode */
        ret = adxl372_set_act_proc_mode(st, ADXL372_LOOPED);
        if (ret < 0)
                return ret;

        ret = adxl372_set_odr(st, ADXL372_ODR_6400HZ);
        if (ret < 0)
                return ret;

        ret = adxl372_set_bandwidth(st, ADXL372_BW_3200HZ);
        if (ret < 0)
                return ret;

        /* Set activity timer to 1ms */
        ret = adxl372_set_activity_time_ms(st, 1);
        if (ret < 0)
                return ret;

        /* Set inactivity timer to 10s */
        ret = adxl372_set_inactivity_time_ms(st, 10000);
        if (ret < 0)
                return ret;

        /* Set the mode of operation to full bandwidth measurement mode */
        return adxl372_set_op_mode(st, ADXL372_FULL_BW_MEASUREMENT);
}

static int adxl372_reg_access(struct iio_dev *indio_dev,
                              unsigned int reg,
                              unsigned int writeval,
                              unsigned int *readval)
{
        struct adxl372_state *st = iio_priv(indio_dev);

        if (readval)
                return regmap_read(st->regmap, reg, readval);
        else
                return regmap_write(st->regmap, reg, writeval);
}

static int adxl372_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long info)
{
        struct adxl372_state *st = iio_priv(indio_dev);
        int ret;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                ret = iio_device_claim_direct_mode(indio_dev);
                if (ret)
                        return ret;

                ret = adxl372_read_axis(st, chan->address);
                iio_device_release_direct_mode(indio_dev);
                if (ret < 0)
                        return ret;

                *val = sign_extend32(ret >> chan->scan_type.shift,
                                     chan->scan_type.realbits - 1);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 0;
                *val2 = ADXL372_USCALE;
                return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = adxl372_samp_freq_tbl[st->odr];
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                *val = adxl372_bw_freq_tbl[st->bw];
                return IIO_VAL_INT;
        }

        return -EINVAL;
}

static int adxl372_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long info)
{
        struct adxl372_state *st = iio_priv(indio_dev);
        int odr_index, bw_index, ret;

        switch (info) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                odr_index = adxl372_find_closest_match(adxl372_samp_freq_tbl,
                                        ARRAY_SIZE(adxl372_samp_freq_tbl),
                                        val);
                ret = adxl372_set_odr(st, odr_index);
                if (ret < 0)
                        return ret;
                /*
                 * The timer period depends on the ODR selected.
                 * At 3200 Hz and below, it is 6.6 ms; at 6400 Hz, it is 3.3 ms
                 */
                ret = adxl372_set_activity_time_ms(st, st->act_time_ms);
                if (ret < 0)
                        return ret;
                /*
                 * The timer period depends on the ODR selected.
                 * At 3200 Hz and below, it is 26 ms; at 6400 Hz, it is 13 ms
                 */
                ret = adxl372_set_inactivity_time_ms(st, st->inact_time_ms);
                if (ret < 0)
                        return ret;
                /*
                 * The maximum bandwidth is constrained to at most half of
                 * the ODR to ensure that the Nyquist criteria is not violated
                 */
                if (st->bw > odr_index)
                        ret = adxl372_set_bandwidth(st, odr_index);

                return ret;
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                bw_index = adxl372_find_closest_match(adxl372_bw_freq_tbl,
                                        ARRAY_SIZE(adxl372_bw_freq_tbl),
                                        val);
                return adxl372_set_bandwidth(st, bw_index);
        default:
                return -EINVAL;
        }
}

static ssize_t adxl372_show_filter_freq_avail(struct device *dev,
                                              struct device_attribute *attr,
                                              char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct adxl372_state *st = iio_priv(indio_dev);
        int i;
        size_t len = 0;

        for (i = 0; i <= st->odr; i++)
                len += scnprintf(buf + len, PAGE_SIZE - len,
                                 "%d ", adxl372_bw_freq_tbl[i]);

        buf[len - 1] = '\n';

        return len;
}

static ssize_t adxl372_get_fifo_enabled(struct device *dev,
                                          struct device_attribute *attr,
                                          char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct adxl372_state *st = iio_priv(indio_dev);

        return sprintf(buf, "%d\n", st->fifo_mode);
}

static ssize_t adxl372_get_fifo_watermark(struct device *dev,
                                          struct device_attribute *attr,
                                          char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct adxl372_state *st = iio_priv(indio_dev);

        return sprintf(buf, "%d\n", st->watermark);
}

static IIO_CONST_ATTR(hwfifo_watermark_min, "1");
static IIO_CONST_ATTR(hwfifo_watermark_max,
                      __stringify(ADXL372_FIFO_SIZE));
static IIO_DEVICE_ATTR(hwfifo_watermark, 0444,
                       adxl372_get_fifo_watermark, NULL, 0);
static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
                       adxl372_get_fifo_enabled, NULL, 0);

static const struct attribute *adxl372_fifo_attributes[] = {
        &iio_const_attr_hwfifo_watermark_min.dev_attr.attr,
        &iio_const_attr_hwfifo_watermark_max.dev_attr.attr,
        &iio_dev_attr_hwfifo_watermark.dev_attr.attr,
        &iio_dev_attr_hwfifo_enabled.dev_attr.attr,
        NULL,
};

static int adxl372_set_watermark(struct iio_dev *indio_dev, unsigned int val)
{
        struct adxl372_state *st  = iio_priv(indio_dev);

        if (val > ADXL372_FIFO_SIZE)
                val = ADXL372_FIFO_SIZE;

        st->watermark = val;

        return 0;
}

static int adxl372_buffer_postenable(struct iio_dev *indio_dev)
{
        struct adxl372_state *st = iio_priv(indio_dev);
        unsigned int mask;
        int i, ret;

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

        ret = adxl372_set_interrupts(st, ADXL372_INT1_MAP_FIFO_FULL_MSK, 0);
        if (ret < 0)
                goto err;

        mask = *indio_dev->active_scan_mask;

        for (i = 0; i < ARRAY_SIZE(adxl372_axis_lookup_table); i++) {
                if (mask == adxl372_axis_lookup_table[i].bits)
                        break;
        }

        if (i == ARRAY_SIZE(adxl372_axis_lookup_table)) {
                ret = -EINVAL;
                goto err;
        }

        st->fifo_format = adxl372_axis_lookup_table[i].fifo_format;
        st->fifo_set_size = bitmap_weight(indio_dev->active_scan_mask,
                                          indio_dev->masklength);
        /*
         * The 512 FIFO samples can be allotted in several ways, such as:
         * 170 sample sets of concurrent 3-axis data
         * 256 sample sets of concurrent 2-axis data (user selectable)
         * 512 sample sets of single-axis data
         */
        if ((st->watermark * st->fifo_set_size) > ADXL372_FIFO_SIZE)
                st->watermark = (ADXL372_FIFO_SIZE  / st->fifo_set_size);

        st->fifo_mode = ADXL372_FIFO_STREAMED;

        ret = adxl372_configure_fifo(st);
        if (ret < 0) {
                st->fifo_mode = ADXL372_FIFO_BYPASSED;
                adxl372_set_interrupts(st, 0, 0);
                goto err;
        }

        return 0;

err:
        iio_triggered_buffer_predisable(indio_dev);
        return ret;
}

static int adxl372_buffer_predisable(struct iio_dev *indio_dev)
{
        struct adxl372_state *st = iio_priv(indio_dev);

        adxl372_set_interrupts(st, 0, 0);
        st->fifo_mode = ADXL372_FIFO_BYPASSED;
        adxl372_configure_fifo(st);

        return iio_triggered_buffer_predisable(indio_dev);
}

static const struct iio_buffer_setup_ops adxl372_buffer_ops = {
        .postenable = adxl372_buffer_postenable,
        .predisable = adxl372_buffer_predisable,
};

static int adxl372_dready_trig_set_state(struct iio_trigger *trig,
                                         bool state)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct adxl372_state *st = iio_priv(indio_dev);
        unsigned long int mask = 0;

        if (state)
                mask = ADXL372_INT1_MAP_FIFO_FULL_MSK;

        return adxl372_set_interrupts(st, mask, 0);
}

static int adxl372_validate_trigger(struct iio_dev *indio_dev,
                                    struct iio_trigger *trig)
{
        struct adxl372_state *st = iio_priv(indio_dev);

        if (st->dready_trig != trig)
                return -EINVAL;

        return 0;
}

static const struct iio_trigger_ops adxl372_trigger_ops = {
        .validate_device = &iio_trigger_validate_own_device,
        .set_trigger_state = adxl372_dready_trig_set_state,
};

static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("400 800 1600 3200 6400");
static IIO_DEVICE_ATTR(in_accel_filter_low_pass_3db_frequency_available,
                       0444, adxl372_show_filter_freq_avail, NULL, 0);

static struct attribute *adxl372_attributes[] = {
        &iio_const_attr_sampling_frequency_available.dev_attr.attr,
        &iio_dev_attr_in_accel_filter_low_pass_3db_frequency_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group adxl372_attrs_group = {
        .attrs = adxl372_attributes,
};

static const struct iio_info adxl372_info = {
        .validate_trigger = &adxl372_validate_trigger,
        .attrs = &adxl372_attrs_group,
        .read_raw = adxl372_read_raw,
        .write_raw = adxl372_write_raw,
        .debugfs_reg_access = &adxl372_reg_access,
        .hwfifo_set_watermark = adxl372_set_watermark,
};

bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg)
{
        return (reg == ADXL372_FIFO_DATA);
}
EXPORT_SYMBOL_GPL(adxl372_readable_noinc_reg);

int adxl372_probe(struct device *dev, struct regmap *regmap,
                  int irq, const char *name)
{
        struct iio_dev *indio_dev;
        struct adxl372_state *st;
        int ret;

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

        st = iio_priv(indio_dev);
        dev_set_drvdata(dev, indio_dev);

        st->dev = dev;
        st->regmap = regmap;
        st->irq = irq;

        indio_dev->channels = adxl372_channels;
        indio_dev->num_channels = ARRAY_SIZE(adxl372_channels);
        indio_dev->available_scan_masks = adxl372_channel_masks;
        indio_dev->dev.parent = dev;
        indio_dev->name = name;
        indio_dev->info = &adxl372_info;
        indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;

        ret = adxl372_setup(st);
        if (ret < 0) {
                dev_err(dev, "ADXL372 setup failed\n");
                return ret;
        }

        ret = devm_iio_triggered_buffer_setup(dev,
                                              indio_dev, NULL,
                                              adxl372_trigger_handler,
                                              &adxl372_buffer_ops);
        if (ret < 0)
                return ret;

        iio_buffer_set_attrs(indio_dev->buffer, adxl372_fifo_attributes);

        if (st->irq) {
                st->dready_trig = devm_iio_trigger_alloc(dev,
                                                         "%s-dev%d",
                                                         indio_dev->name,
                                                         indio_dev->id);
                if (st->dready_trig == NULL)
                        return -ENOMEM;

                st->dready_trig->ops = &adxl372_trigger_ops;
                st->dready_trig->dev.parent = dev;
                iio_trigger_set_drvdata(st->dready_trig, indio_dev);
                ret = devm_iio_trigger_register(dev, st->dready_trig);
                if (ret < 0)
                        return ret;

                indio_dev->trig = iio_trigger_get(st->dready_trig);

                ret = devm_request_threaded_irq(dev, st->irq,
                                        iio_trigger_generic_data_rdy_poll,
                                        NULL,
                                        IRQF_TRIGGER_RISING | IRQF_ONESHOT,
                                        indio_dev->name, st->dready_trig);
                if (ret < 0)
                        return ret;
        }

        return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_GPL(adxl372_probe);

MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer driver");
MODULE_LICENSE("GPL");