// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ADXRS290 SPI Gyroscope Driver
 *
 * Copyright (C) 2020 Nishant Malpani <nish.malpani25@gmail.com>
 * Copyright (C) 2020 Analog Devices, Inc.
 */

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spi/spi.h>

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

#define ADXRS290_ADI_ID         0xAD
#define ADXRS290_MEMS_ID        0x1D
#define ADXRS290_DEV_ID         0x92

#define ADXRS290_REG_ADI_ID     0x00
#define ADXRS290_REG_MEMS_ID    0x01
#define ADXRS290_REG_DEV_ID     0x02
#define ADXRS290_REG_REV_ID     0x03
#define ADXRS290_REG_SN0        0x04 /* Serial Number Registers, 4 bytes */
#define ADXRS290_REG_DATAX0     0x08 /* Roll Rate o/p Data Regs, 2 bytes */
#define ADXRS290_REG_DATAY0     0x0A /* Pitch Rate o/p Data Regs, 2 bytes */
#define ADXRS290_REG_TEMP0      0x0C
#define ADXRS290_REG_POWER_CTL  0x10
#define ADXRS290_REG_FILTER     0x11
#define ADXRS290_REG_DATA_RDY   0x12

#define ADXRS290_READ           BIT(7)
#define ADXRS290_TSM            BIT(0)
#define ADXRS290_MEASUREMENT    BIT(1)
#define ADXRS290_DATA_RDY_OUT   BIT(0)
#define ADXRS290_SYNC_MASK      GENMASK(1, 0)
#define ADXRS290_SYNC(x)        FIELD_PREP(ADXRS290_SYNC_MASK, x)
#define ADXRS290_LPF_MASK       GENMASK(2, 0)
#define ADXRS290_LPF(x)         FIELD_PREP(ADXRS290_LPF_MASK, x)
#define ADXRS290_HPF_MASK       GENMASK(7, 4)
#define ADXRS290_HPF(x)         FIELD_PREP(ADXRS290_HPF_MASK, x)

#define ADXRS290_READ_REG(reg)  (ADXRS290_READ | (reg))

#define ADXRS290_MAX_TRANSITION_TIME_MS 100

enum adxrs290_mode {
        ADXRS290_MODE_STANDBY,
        ADXRS290_MODE_MEASUREMENT,
};

enum adxrs290_scan_index {
        ADXRS290_IDX_X,
        ADXRS290_IDX_Y,
        ADXRS290_IDX_TEMP,
        ADXRS290_IDX_TS,
};

struct adxrs290_state {
        struct spi_device       *spi;
        /* Serialize reads and their subsequent processing */
        struct mutex            lock;
        enum adxrs290_mode      mode;
        unsigned int            lpf_3db_freq_idx;
        unsigned int            hpf_3db_freq_idx;
        struct iio_trigger      *dready_trig;
        /* Ensure correct alignment of timestamp when present */
        struct {
                s16 channels[3];
                aligned_s64 ts;
        } buffer;
};

/*
 * Available cut-off frequencies of the low pass filter in Hz.
 * The integer part and fractional part are represented separately.
 */
static const int adxrs290_lpf_3db_freq_hz_table[][2] = {
        [0] = {480, 0},
        [1] = {320, 0},
        [2] = {160, 0},
        [3] = {80, 0},
        [4] = {56, 600000},
        [5] = {40, 0},
        [6] = {28, 300000},
        [7] = {20, 0},
};

/*
 * Available cut-off frequencies of the high pass filter in Hz.
 * The integer part and fractional part are represented separately.
 */
static const int adxrs290_hpf_3db_freq_hz_table[][2] = {
        [0] = {0, 0},
        [1] = {0, 11000},
        [2] = {0, 22000},
        [3] = {0, 44000},
        [4] = {0, 87000},
        [5] = {0, 175000},
        [6] = {0, 350000},
        [7] = {0, 700000},
        [8] = {1, 400000},
        [9] = {2, 800000},
        [10] = {11, 300000},
};

static int adxrs290_get_rate_data(struct iio_dev *indio_dev, const u8 cmd, int *val)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        int ret = 0;
        int temp;

        mutex_lock(&st->lock);
        temp = spi_w8r16(st->spi, cmd);
        if (temp < 0) {
                ret = temp;
                goto err_unlock;
        }

        *val = sign_extend32(temp, 15);

err_unlock:
        mutex_unlock(&st->lock);
        return ret;
}

static int adxrs290_get_temp_data(struct iio_dev *indio_dev, int *val)
{
        const u8 cmd = ADXRS290_READ_REG(ADXRS290_REG_TEMP0);
        struct adxrs290_state *st = iio_priv(indio_dev);
        int ret = 0;
        int temp;

        mutex_lock(&st->lock);
        temp = spi_w8r16(st->spi, cmd);
        if (temp < 0) {
                ret = temp;
                goto err_unlock;
        }

        /* extract lower 12 bits temperature reading */
        *val = sign_extend32(temp, 11);

err_unlock:
        mutex_unlock(&st->lock);
        return ret;
}

static int adxrs290_get_3db_freq(struct iio_dev *indio_dev, u8 *val, u8 *val2)
{
        const u8 cmd = ADXRS290_READ_REG(ADXRS290_REG_FILTER);
        struct adxrs290_state *st = iio_priv(indio_dev);
        int ret = 0;
        short temp;

        mutex_lock(&st->lock);
        temp = spi_w8r8(st->spi, cmd);
        if (temp < 0) {
                ret = temp;
                goto err_unlock;
        }

        *val = FIELD_GET(ADXRS290_LPF_MASK, temp);
        *val2 = FIELD_GET(ADXRS290_HPF_MASK, temp);

err_unlock:
        mutex_unlock(&st->lock);
        return ret;
}

static int adxrs290_spi_write_reg(struct spi_device *spi, const u8 reg,
                                  const u8 val)
{
        u8 buf[2];

        buf[0] = reg;
        buf[1] = val;

        return spi_write_then_read(spi, buf, ARRAY_SIZE(buf), NULL, 0);
}

static int adxrs290_find_match(const int (*freq_tbl)[2], const int n,
                               const int val, const int val2)
{
        int i;

        for (i = 0; i < n; i++) {
                if (freq_tbl[i][0] == val && freq_tbl[i][1] == val2)
                        return i;
        }

        return -EINVAL;
}

static int adxrs290_set_filter_freq(struct iio_dev *indio_dev,
                                    const unsigned int lpf_idx,
                                    const unsigned int hpf_idx)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        u8 val;

        val = ADXRS290_HPF(hpf_idx) | ADXRS290_LPF(lpf_idx);

        return adxrs290_spi_write_reg(st->spi, ADXRS290_REG_FILTER, val);
}

static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        int val, ret;

        if (st->mode == mode)
                return 0;

        mutex_lock(&st->lock);

        ret = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
        if (ret < 0)
                goto out_unlock;

        val = ret;

        switch (mode) {
        case ADXRS290_MODE_STANDBY:
                val &= ~ADXRS290_MEASUREMENT;
                break;
        case ADXRS290_MODE_MEASUREMENT:
                val |= ADXRS290_MEASUREMENT;
                break;
        default:
                ret = -EINVAL;
                goto out_unlock;
        }

        ret = adxrs290_spi_write_reg(st->spi, ADXRS290_REG_POWER_CTL, val);
        if (ret < 0) {
                dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
                goto out_unlock;
        }

        /* update cached mode */
        st->mode = mode;

out_unlock:
        mutex_unlock(&st->lock);
        return ret;
}

static void adxrs290_chip_off_action(void *data)
{
        struct iio_dev *indio_dev = data;

        adxrs290_set_mode(indio_dev, ADXRS290_MODE_STANDBY);
}

static int adxrs290_initial_setup(struct iio_dev *indio_dev)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        struct spi_device *spi = st->spi;
        int ret;

        ret = adxrs290_spi_write_reg(spi, ADXRS290_REG_POWER_CTL,
                                     ADXRS290_MEASUREMENT | ADXRS290_TSM);
        if (ret < 0)
                return ret;

        st->mode = ADXRS290_MODE_MEASUREMENT;

        return devm_add_action_or_reset(&spi->dev, adxrs290_chip_off_action,
                                        indio_dev);
}

static int adxrs290_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int *val,
                             int *val2,
                             long mask)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        unsigned int t;
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;

                switch (chan->type) {
                case IIO_ANGL_VEL:
                        ret = adxrs290_get_rate_data(indio_dev,
                                                     ADXRS290_READ_REG(chan->address),
                                                     val);
                        if (ret < 0)
                                break;

                        ret = IIO_VAL_INT;
                        break;
                case IIO_TEMP:
                        ret = adxrs290_get_temp_data(indio_dev, val);
                        if (ret < 0)
                                break;

                        ret = IIO_VAL_INT;
                        break;
                default:
                        ret = -EINVAL;
                        break;
                }

                iio_device_release_direct(indio_dev);
                return ret;
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        /* 1 LSB = 0.005 degrees/sec */
                        *val = 0;
                        *val2 = 87266;
                        return IIO_VAL_INT_PLUS_NANO;
                case IIO_TEMP:
                        /* 1 LSB = 0.1 degrees Celsius */
                        *val = 100;
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        t = st->lpf_3db_freq_idx;
                        *val = adxrs290_lpf_3db_freq_hz_table[t][0];
                        *val2 = adxrs290_lpf_3db_freq_hz_table[t][1];
                        return IIO_VAL_INT_PLUS_MICRO;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        t = st->hpf_3db_freq_idx;
                        *val = adxrs290_hpf_3db_freq_hz_table[t][0];
                        *val2 = adxrs290_hpf_3db_freq_hz_table[t][1];
                        return IIO_VAL_INT_PLUS_MICRO;
                default:
                        return -EINVAL;
                }
        }

        return -EINVAL;
}

static int adxrs290_write_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int val,
                              int val2,
                              long mask)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        int ret, lpf_idx, hpf_idx;

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

        switch (mask) {
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                lpf_idx = adxrs290_find_match(adxrs290_lpf_3db_freq_hz_table,
                                              ARRAY_SIZE(adxrs290_lpf_3db_freq_hz_table),
                                              val, val2);
                if (lpf_idx < 0) {
                        ret = -EINVAL;
                        break;
                }

                /* caching the updated state of the low-pass filter */
                st->lpf_3db_freq_idx = lpf_idx;
                /* retrieving the current state of the high-pass filter */
                hpf_idx = st->hpf_3db_freq_idx;
                ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
                break;

        case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
                hpf_idx = adxrs290_find_match(adxrs290_hpf_3db_freq_hz_table,
                                              ARRAY_SIZE(adxrs290_hpf_3db_freq_hz_table),
                                              val, val2);
                if (hpf_idx < 0) {
                        ret = -EINVAL;
                        break;
                }

                /* caching the updated state of the high-pass filter */
                st->hpf_3db_freq_idx = hpf_idx;
                /* retrieving the current state of the low-pass filter */
                lpf_idx = st->lpf_3db_freq_idx;
                ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
                break;

        default:
                ret = -EINVAL;
                break;
        }

        iio_device_release_direct(indio_dev);
        return ret;
}

static int adxrs290_read_avail(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               const int **vals, int *type, int *length,
                               long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                *vals = (const int *)adxrs290_lpf_3db_freq_hz_table;
                *type = IIO_VAL_INT_PLUS_MICRO;
                /* Values are stored in a 2D matrix */
                *length = ARRAY_SIZE(adxrs290_lpf_3db_freq_hz_table) * 2;

                return IIO_AVAIL_LIST;
        case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
                *vals = (const int *)adxrs290_hpf_3db_freq_hz_table;
                *type = IIO_VAL_INT_PLUS_MICRO;
                /* Values are stored in a 2D matrix */
                *length = ARRAY_SIZE(adxrs290_hpf_3db_freq_hz_table) * 2;

                return IIO_AVAIL_LIST;
        default:
                return -EINVAL;
        }
}

static int adxrs290_reg_access_rw(struct spi_device *spi, unsigned int reg,
                                  unsigned int *readval)
{
        int ret;

        ret = spi_w8r8(spi, ADXRS290_READ_REG(reg));
        if (ret < 0)
                return ret;

        *readval = ret;

        return 0;
}

static int adxrs290_reg_access(struct iio_dev *indio_dev, unsigned int reg,
                               unsigned int writeval, unsigned int *readval)
{
        struct adxrs290_state *st = iio_priv(indio_dev);

        if (readval)
                return adxrs290_reg_access_rw(st->spi, reg, readval);
        else
                return adxrs290_spi_write_reg(st->spi, reg, writeval);
}

static int adxrs290_data_rdy_trigger_set_state(struct iio_trigger *trig,
                                               bool state)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct adxrs290_state *st = iio_priv(indio_dev);
        int ret;
        u8 val;

        val = state ? ADXRS290_SYNC(ADXRS290_DATA_RDY_OUT) : 0;

        ret = adxrs290_spi_write_reg(st->spi, ADXRS290_REG_DATA_RDY, val);
        if (ret < 0)
                dev_err(&st->spi->dev, "failed to start data rdy interrupt\n");

        return ret;
}

static void adxrs290_reset_trig(struct iio_trigger *trig)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        int val;

        /*
         * Data ready interrupt is reset after a read of the data registers.
         * Here, we only read the 16b DATAY registers as that marks the end of
         * a read of the data registers and initiates a reset for the interrupt
         * line.
         */
        adxrs290_get_rate_data(indio_dev,
                               ADXRS290_READ_REG(ADXRS290_REG_DATAY0), &val);
}

static const struct iio_trigger_ops adxrs290_trigger_ops = {
        .set_trigger_state = &adxrs290_data_rdy_trigger_set_state,
        .validate_device = &iio_trigger_validate_own_device,
        .reenable = &adxrs290_reset_trig,
};

static irqreturn_t adxrs290_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct adxrs290_state *st = iio_priv(indio_dev);
        u8 tx = ADXRS290_READ_REG(ADXRS290_REG_DATAX0);
        int ret;

        mutex_lock(&st->lock);

        /* exercise a bulk data capture starting from reg DATAX0... */
        ret = spi_write_then_read(st->spi, &tx, sizeof(tx), st->buffer.channels,
                                  sizeof(st->buffer.channels));
        if (ret < 0)
                goto out_unlock_notify;

        iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
                                           pf->timestamp);

out_unlock_notify:
        mutex_unlock(&st->lock);
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

#define ADXRS290_ANGL_VEL_CHANNEL(reg, axis) {                          \
        .type = IIO_ANGL_VEL,                                           \
        .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_LOW_PASS_FILTER_3DB_FREQUENCY) |              \
        BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),              \
        .info_mask_shared_by_type_available =                           \
        BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |              \
        BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),              \
        .scan_index = ADXRS290_IDX_##axis,                              \
        .scan_type = {                                                  \
                .sign = 's',                                            \
                .realbits = 16,                                         \
                .storagebits = 16,                                      \
                .endianness = IIO_LE,                                   \
        },                                                              \
}

static const struct iio_chan_spec adxrs290_channels[] = {
        ADXRS290_ANGL_VEL_CHANNEL(ADXRS290_REG_DATAX0, X),
        ADXRS290_ANGL_VEL_CHANNEL(ADXRS290_REG_DATAY0, Y),
        {
                .type = IIO_TEMP,
                .address = ADXRS290_REG_TEMP0,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                BIT(IIO_CHAN_INFO_SCALE),
                .scan_index = ADXRS290_IDX_TEMP,
                .scan_type = {
                        .sign = 's',
                        .realbits = 12,
                        .storagebits = 16,
                        .endianness = IIO_LE,
                },
        },
        IIO_CHAN_SOFT_TIMESTAMP(ADXRS290_IDX_TS),
};

static const unsigned long adxrs290_avail_scan_masks[] = {
        BIT(ADXRS290_IDX_X) | BIT(ADXRS290_IDX_Y) | BIT(ADXRS290_IDX_TEMP),
        0
};

static const struct iio_info adxrs290_info = {
        .read_raw = &adxrs290_read_raw,
        .write_raw = &adxrs290_write_raw,
        .read_avail = &adxrs290_read_avail,
        .debugfs_reg_access = &adxrs290_reg_access,
};

static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
{
        struct adxrs290_state *st = iio_priv(indio_dev);
        int ret;

        if (!st->spi->irq) {
                dev_info(&st->spi->dev, "no irq, using polling\n");
                return 0;
        }

        st->dready_trig = devm_iio_trigger_alloc(&st->spi->dev, "%s-dev%d",
                                                 indio_dev->name,
                                                 iio_device_id(indio_dev));
        if (!st->dready_trig)
                return -ENOMEM;

        st->dready_trig->ops = &adxrs290_trigger_ops;
        iio_trigger_set_drvdata(st->dready_trig, indio_dev);

        ret = devm_request_irq(&st->spi->dev, st->spi->irq,
                               &iio_trigger_generic_data_rdy_poll,
                               IRQF_NO_THREAD, "adxrs290_irq", st->dready_trig);
        if (ret < 0)
                return dev_err_probe(&st->spi->dev, ret,
                                     "request irq %d failed\n", st->spi->irq);

        ret = devm_iio_trigger_register(&st->spi->dev, st->dready_trig);
        if (ret) {
                dev_err(&st->spi->dev, "iio trigger register failed\n");
                return ret;
        }

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

        return 0;
}

static int adxrs290_probe(struct spi_device *spi)
{
        struct iio_dev *indio_dev;
        struct adxrs290_state *st;
        u8 val, val2;
        int ret;

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

        st = iio_priv(indio_dev);
        st->spi = spi;

        indio_dev->name = "adxrs290";
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = adxrs290_channels;
        indio_dev->num_channels = ARRAY_SIZE(adxrs290_channels);
        indio_dev->info = &adxrs290_info;
        indio_dev->available_scan_masks = adxrs290_avail_scan_masks;

        mutex_init(&st->lock);

        val = spi_w8r8(spi, ADXRS290_READ_REG(ADXRS290_REG_ADI_ID));
        if (val != ADXRS290_ADI_ID) {
                dev_err(&spi->dev, "Wrong ADI ID 0x%02x\n", val);
                return -ENODEV;
        }

        val = spi_w8r8(spi, ADXRS290_READ_REG(ADXRS290_REG_MEMS_ID));
        if (val != ADXRS290_MEMS_ID) {
                dev_err(&spi->dev, "Wrong MEMS ID 0x%02x\n", val);
                return -ENODEV;
        }

        val = spi_w8r8(spi, ADXRS290_READ_REG(ADXRS290_REG_DEV_ID));
        if (val != ADXRS290_DEV_ID) {
                dev_err(&spi->dev, "Wrong DEV ID 0x%02x\n", val);
                return -ENODEV;
        }

        /* default mode the gyroscope starts in */
        st->mode = ADXRS290_MODE_STANDBY;

        /* switch to measurement mode and switch on the temperature sensor */
        ret = adxrs290_initial_setup(indio_dev);
        if (ret < 0)
                return ret;

        /* max transition time to measurement mode */
        msleep(ADXRS290_MAX_TRANSITION_TIME_MS);

        ret = adxrs290_get_3db_freq(indio_dev, &val, &val2);
        if (ret < 0)
                return ret;

        st->lpf_3db_freq_idx = val;
        st->hpf_3db_freq_idx = val2;

        ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
                                              &iio_pollfunc_store_time,
                                              &adxrs290_trigger_handler, NULL);
        if (ret < 0)
                return dev_err_probe(&spi->dev, ret,
                                     "iio triggered buffer setup failed\n");

        ret = adxrs290_probe_trigger(indio_dev);
        if (ret < 0)
                return ret;

        return devm_iio_device_register(&spi->dev, indio_dev);
}

static const struct of_device_id adxrs290_of_match[] = {
        { .compatible = "adi,adxrs290" },
        { }
};
MODULE_DEVICE_TABLE(of, adxrs290_of_match);

static struct spi_driver adxrs290_driver = {
        .driver = {
                .name = "adxrs290",
                .of_match_table = adxrs290_of_match,
        },
        .probe = adxrs290_probe,
};
module_spi_driver(adxrs290_driver);

MODULE_AUTHOR("Nishant Malpani <nish.malpani25@gmail.com>");
MODULE_DESCRIPTION("Analog Devices ADXRS290 Gyroscope SPI driver");
MODULE_LICENSE("GPL");