// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2020 InvenSense, Inc.
 *
 * Driver for InvenSense ICP-1010xx barometric pressure and temperature sensor.
 *
 * Datasheet:
 * http://www.invensense.com/wp-content/uploads/2018/01/DS-000186-ICP-101xx-v1.2.pdf
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/i2c.h>
#include <linux/pm_runtime.h>
#include <linux/crc8.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/math64.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/iio.h>

#define ICP10100_ID_REG_GET(_reg)       ((_reg) & 0x003F)
#define ICP10100_ID_REG                 0x08
#define ICP10100_RESPONSE_WORD_LENGTH   3
#define ICP10100_CRC8_WORD_LENGTH       2
#define ICP10100_CRC8_POLYNOMIAL        0x31
#define ICP10100_CRC8_INIT              0xFF

enum icp10100_mode {
        ICP10100_MODE_LP,       /* Low power mode: 1x sampling */
        ICP10100_MODE_N,        /* Normal mode: 2x sampling */
        ICP10100_MODE_LN,       /* Low noise mode: 4x sampling */
        ICP10100_MODE_ULN,      /* Ultra low noise mode: 8x sampling */
        ICP10100_MODE_NB,
};

struct icp10100_state {
        struct mutex lock;
        struct i2c_client *client;
        struct regulator *vdd;
        enum icp10100_mode mode;
        int16_t cal[4];
};

struct icp10100_command {
        __be16 cmd;
        unsigned long wait_us;
        unsigned long wait_max_us;
        size_t response_word_nb;
};

static const struct icp10100_command icp10100_cmd_soft_reset = {
        .cmd = cpu_to_be16(0x805D),
        .wait_us = 170,
        .wait_max_us = 200,
        .response_word_nb = 0,
};

static const struct icp10100_command icp10100_cmd_read_id = {
        .cmd = cpu_to_be16(0xEFC8),
        .wait_us = 0,
        .response_word_nb = 1,
};

static const struct icp10100_command icp10100_cmd_read_otp = {
        .cmd = cpu_to_be16(0xC7F7),
        .wait_us = 0,
        .response_word_nb = 1,
};

static const struct icp10100_command icp10100_cmd_measure[] = {
        [ICP10100_MODE_LP] = {
                .cmd = cpu_to_be16(0x401A),
                .wait_us = 1800,
                .wait_max_us = 2000,
                .response_word_nb = 3,
        },
        [ICP10100_MODE_N] = {
                .cmd = cpu_to_be16(0x48A3),
                .wait_us = 6300,
                .wait_max_us = 6500,
                .response_word_nb = 3,
        },
        [ICP10100_MODE_LN] = {
                .cmd = cpu_to_be16(0x5059),
                .wait_us = 23800,
                .wait_max_us = 24000,
                .response_word_nb = 3,
        },
        [ICP10100_MODE_ULN] = {
                .cmd = cpu_to_be16(0x58E0),
                .wait_us = 94500,
                .wait_max_us = 94700,
                .response_word_nb = 3,
        },
};

static const uint8_t icp10100_switch_mode_otp[] =
        {0xC5, 0x95, 0x00, 0x66, 0x9c};

DECLARE_CRC8_TABLE(icp10100_crc8_table);

static inline int icp10100_i2c_xfer(struct i2c_adapter *adap,
                                    struct i2c_msg *msgs, int num)
{
        int ret;

        ret = i2c_transfer(adap, msgs, num);
        if (ret < 0)
                return ret;

        if (ret != num)
                return -EIO;

        return 0;
}

static int icp10100_send_cmd(struct icp10100_state *st,
                             const struct icp10100_command *cmd,
                             __be16 *buf, size_t buf_len)
{
        size_t size = cmd->response_word_nb * ICP10100_RESPONSE_WORD_LENGTH;
        uint8_t data[16];
        uint8_t *ptr;
        uint8_t *buf_ptr = (uint8_t *)buf;
        struct i2c_msg msgs[2] = {
                {
                        .addr = st->client->addr,
                        .flags = 0,
                        .len = 2,
                        .buf = (uint8_t *)&cmd->cmd,
                }, {
                        .addr = st->client->addr,
                        .flags = I2C_M_RD,
                        .len = size,
                        .buf = data,
                },
        };
        uint8_t crc;
        unsigned int i;
        int ret;

        if (size > sizeof(data))
                return -EINVAL;

        if (cmd->response_word_nb > 0 &&
                        (buf == NULL || buf_len < (cmd->response_word_nb * 2)))
                return -EINVAL;

        dev_dbg(&st->client->dev, "sending cmd %#x\n", be16_to_cpu(cmd->cmd));

        if (cmd->response_word_nb > 0 && cmd->wait_us == 0) {
                /* direct command-response without waiting */
                ret = icp10100_i2c_xfer(st->client->adapter, msgs,
                                        ARRAY_SIZE(msgs));
                if (ret)
                        return ret;
        } else {
                /* transfer command write */
                ret = icp10100_i2c_xfer(st->client->adapter, &msgs[0], 1);
                if (ret)
                        return ret;
                if (cmd->wait_us > 0)
                        usleep_range(cmd->wait_us, cmd->wait_max_us);
                /* transfer response read if needed */
                if (cmd->response_word_nb > 0) {
                        ret = icp10100_i2c_xfer(st->client->adapter, &msgs[1], 1);
                        if (ret)
                                return ret;
                } else {
                        return 0;
                }
        }

        /* process read words with crc checking */
        for (i = 0; i < cmd->response_word_nb; ++i) {
                ptr = &data[i * ICP10100_RESPONSE_WORD_LENGTH];
                crc = crc8(icp10100_crc8_table, ptr, ICP10100_CRC8_WORD_LENGTH,
                           ICP10100_CRC8_INIT);
                if (crc != ptr[ICP10100_CRC8_WORD_LENGTH]) {
                        dev_err(&st->client->dev, "crc error recv=%#x calc=%#x\n",
                                ptr[ICP10100_CRC8_WORD_LENGTH], crc);
                        return -EIO;
                }
                *buf_ptr++ = ptr[0];
                *buf_ptr++ = ptr[1];
        }

        return 0;
}

static int icp10100_read_cal_otp(struct icp10100_state *st)
{
        __be16 val;
        int i;
        int ret;

        /* switch into OTP read mode */
        ret = i2c_master_send(st->client, icp10100_switch_mode_otp,
                              ARRAY_SIZE(icp10100_switch_mode_otp));
        if (ret < 0)
                return ret;
        if (ret != ARRAY_SIZE(icp10100_switch_mode_otp))
                return -EIO;

        /* read 4 calibration values */
        for (i = 0; i < 4; ++i) {
                ret = icp10100_send_cmd(st, &icp10100_cmd_read_otp,
                                        &val, sizeof(val));
                if (ret)
                        return ret;
                st->cal[i] = be16_to_cpu(val);
                dev_dbg(&st->client->dev, "cal[%d] = %d\n", i, st->cal[i]);
        }

        return 0;
}

static int icp10100_init_chip(struct icp10100_state *st)
{
        __be16 val;
        uint16_t id;
        int ret;

        /* read and check id */
        ret = icp10100_send_cmd(st, &icp10100_cmd_read_id, &val, sizeof(val));
        if (ret)
                return ret;
        id = ICP10100_ID_REG_GET(be16_to_cpu(val));
        if (id != ICP10100_ID_REG) {
                dev_err(&st->client->dev, "invalid id %#x\n", id);
                return -ENODEV;
        }

        /* read calibration data from OTP */
        ret = icp10100_read_cal_otp(st);
        if (ret)
                return ret;

        /* reset chip */
        return icp10100_send_cmd(st, &icp10100_cmd_soft_reset, NULL, 0);
}

static int icp10100_get_measures(struct icp10100_state *st,
                                uint32_t *pressure, uint16_t *temperature)
{
        const struct icp10100_command *cmd;
        __be16 measures[3];
        int ret;

        ret = pm_runtime_resume_and_get(&st->client->dev);
        if (ret < 0)
                return ret;

        mutex_lock(&st->lock);
        cmd = &icp10100_cmd_measure[st->mode];
        ret = icp10100_send_cmd(st, cmd, measures, sizeof(measures));
        mutex_unlock(&st->lock);
        if (ret)
                goto error_measure;

        *pressure = (be16_to_cpu(measures[0]) << 8) |
                        (be16_to_cpu(measures[1]) >> 8);
        *temperature = be16_to_cpu(measures[2]);

error_measure:
        pm_runtime_put_autosuspend(&st->client->dev);
        return ret;
}

static uint32_t icp10100_get_pressure(struct icp10100_state *st,
                                      uint32_t raw_pressure, uint16_t raw_temp)
{
        static int32_t p_calib[] = {45000, 80000, 105000};
        static int32_t lut_lower = 3670016;
        static int32_t lut_upper = 12058624;
        static int32_t inv_quadr_factor = 16777216;
        static int32_t offset_factor = 2048;
        int64_t val1, val2;
        int32_t p_lut[3];
        int32_t t, t_square;
        int64_t a, b, c;
        uint32_t pressure_mPa;

        dev_dbg(&st->client->dev, "raw: pressure = %u, temp = %u\n",
                raw_pressure, raw_temp);

        /* compute p_lut values */
        t = (int32_t)raw_temp - 32768;
        t_square = t * t;
        val1 = (int64_t)st->cal[0] * (int64_t)t_square;
        p_lut[0] = lut_lower + (int32_t)div_s64(val1, inv_quadr_factor);
        val1 = (int64_t)st->cal[1] * (int64_t)t_square;
        p_lut[1] = offset_factor * st->cal[3] +
                        (int32_t)div_s64(val1, inv_quadr_factor);
        val1 = (int64_t)st->cal[2] * (int64_t)t_square;
        p_lut[2] = lut_upper + (int32_t)div_s64(val1, inv_quadr_factor);
        dev_dbg(&st->client->dev, "p_lut = [%d, %d, %d]\n",
                p_lut[0], p_lut[1], p_lut[2]);

        /* compute a, b, c factors */
        val1 = (int64_t)p_lut[0] * (int64_t)p_lut[1] *
                        (int64_t)(p_calib[0] - p_calib[1]) +
                (int64_t)p_lut[1] * (int64_t)p_lut[2] *
                        (int64_t)(p_calib[1] - p_calib[2]) +
                (int64_t)p_lut[2] * (int64_t)p_lut[0] *
                        (int64_t)(p_calib[2] - p_calib[0]);
        val2 = (int64_t)p_lut[2] * (int64_t)(p_calib[0] - p_calib[1]) +
                (int64_t)p_lut[0] * (int64_t)(p_calib[1] - p_calib[2]) +
                (int64_t)p_lut[1] * (int64_t)(p_calib[2] - p_calib[0]);
        c = div64_s64(val1, val2);
        dev_dbg(&st->client->dev, "val1 = %lld, val2 = %lld, c = %lld\n",
                val1, val2, c);
        val1 = (int64_t)p_calib[0] * (int64_t)p_lut[0] -
                (int64_t)p_calib[1] * (int64_t)p_lut[1] -
                (int64_t)(p_calib[1] - p_calib[0]) * c;
        val2 = (int64_t)p_lut[0] - (int64_t)p_lut[1];
        a = div64_s64(val1, val2);
        dev_dbg(&st->client->dev, "val1 = %lld, val2 = %lld, a = %lld\n",
                val1, val2, a);
        b = ((int64_t)p_calib[0] - a) * ((int64_t)p_lut[0] + c);
        dev_dbg(&st->client->dev, "b = %lld\n", b);

        /*
         * pressure_Pa = a + (b / (c + raw_pressure))
         * pressure_mPa = 1000 * pressure_Pa
         */
        pressure_mPa = 1000LL * a + div64_s64(1000LL * b, c + raw_pressure);

        return pressure_mPa;
}

static int icp10100_read_raw_measures(struct iio_dev *indio_dev,
                                      struct iio_chan_spec const *chan,
                                      int *val, int *val2)
{
        struct icp10100_state *st = iio_priv(indio_dev);
        uint32_t raw_pressure;
        uint16_t raw_temp;
        uint32_t pressure_mPa;
        int ret;

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

        ret = icp10100_get_measures(st, &raw_pressure, &raw_temp);
        if (ret)
                goto error_release;

        switch (chan->type) {
        case IIO_PRESSURE:
                pressure_mPa = icp10100_get_pressure(st, raw_pressure,
                                                     raw_temp);
                /* mPa to kPa */
                *val = pressure_mPa / 1000000;
                *val2 = pressure_mPa % 1000000;
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        case IIO_TEMP:
                *val = raw_temp;
                ret = IIO_VAL_INT;
                break;
        default:
                ret = -EINVAL;
                break;
        }

error_release:
        iio_device_release_direct(indio_dev);
        return ret;
}

static int icp10100_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int *val, int *val2, long mask)
{
        struct icp10100_state *st = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
        case IIO_CHAN_INFO_PROCESSED:
                return icp10100_read_raw_measures(indio_dev, chan, val, val2);
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_TEMP:
                        /* 1000 * 175°C / 65536 in m°C */
                        *val = 2;
                        *val2 = 670288;
                        return IIO_VAL_INT_PLUS_MICRO;
                default:
                        return -EINVAL;
                }
                break;
        case IIO_CHAN_INFO_OFFSET:
                switch (chan->type) {
                case IIO_TEMP:
                        /* 1000 * -45°C in m°C */
                        *val = -45000;
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
                break;
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                mutex_lock(&st->lock);
                *val = 1 << st->mode;
                mutex_unlock(&st->lock);
                return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
}

static int icp10100_read_avail(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               const int **vals, int *type, int *length,
                               long mask)
{
        static int oversamplings[] = {1, 2, 4, 8};

        switch (mask) {
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                *vals = oversamplings;
                *type = IIO_VAL_INT;
                *length = ARRAY_SIZE(oversamplings);
                return IIO_AVAIL_LIST;
        default:
                return -EINVAL;
        }
}

static int icp10100_write_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int val, int val2, long mask)
{
        struct icp10100_state *st = iio_priv(indio_dev);
        unsigned int mode;

        switch (mask) {
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                /* oversampling is always positive and a power of 2 */
                if (val <= 0 || !is_power_of_2(val))
                        return -EINVAL;
                mode = ilog2(val);
                if (mode >= ICP10100_MODE_NB)
                        return -EINVAL;
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                mutex_lock(&st->lock);
                st->mode = mode;
                mutex_unlock(&st->lock);
                iio_device_release_direct(indio_dev);
                return 0;
        default:
                return -EINVAL;
        }
}

static int icp10100_write_raw_get_fmt(struct iio_dev *indio_dev,
                                      struct iio_chan_spec const *chan,
                                      long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
}

static const struct iio_info icp10100_info = {
        .read_raw = icp10100_read_raw,
        .read_avail = icp10100_read_avail,
        .write_raw = icp10100_write_raw,
        .write_raw_get_fmt = icp10100_write_raw_get_fmt,
};

static const struct iio_chan_spec icp10100_channels[] = {
        {
                .type = IIO_PRESSURE,
                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
                .info_mask_shared_by_all =
                        BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
                .info_mask_shared_by_all_available =
                        BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
        }, {
                .type = IIO_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_SCALE) |
                        BIT(IIO_CHAN_INFO_OFFSET),
                .info_mask_shared_by_all =
                        BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
                .info_mask_shared_by_all_available =
                        BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
        },
};

static int icp10100_enable_regulator(struct icp10100_state *st)
{
        int ret;

        ret = regulator_enable(st->vdd);
        if (ret)
                return ret;
        msleep(100);

        return 0;
}

static void icp10100_disable_regulator_action(void *data)
{
        struct icp10100_state *st = data;
        int ret;

        ret = regulator_disable(st->vdd);
        if (ret)
                dev_err(&st->client->dev, "error %d disabling vdd\n", ret);
}

static void icp10100_pm_disable(void *data)
{
        struct device *dev = data;

        pm_runtime_disable(dev);
}

static int icp10100_probe(struct i2c_client *client)
{
        struct iio_dev *indio_dev;
        struct icp10100_state *st;
        int ret;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                dev_err(&client->dev, "plain i2c transactions not supported\n");
                return -ENODEV;
        }

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

        i2c_set_clientdata(client, indio_dev);
        indio_dev->name = client->name;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = icp10100_channels;
        indio_dev->num_channels = ARRAY_SIZE(icp10100_channels);
        indio_dev->info = &icp10100_info;

        st = iio_priv(indio_dev);
        mutex_init(&st->lock);
        st->client = client;
        st->mode = ICP10100_MODE_N;

        st->vdd = devm_regulator_get(&client->dev, "vdd");
        if (IS_ERR(st->vdd))
                return PTR_ERR(st->vdd);

        ret = icp10100_enable_regulator(st);
        if (ret)
                return ret;

        ret = devm_add_action_or_reset(&client->dev,
                                       icp10100_disable_regulator_action, st);
        if (ret)
                return ret;

        /* has to be done before the first i2c communication */
        crc8_populate_msb(icp10100_crc8_table, ICP10100_CRC8_POLYNOMIAL);

        ret = icp10100_init_chip(st);
        if (ret) {
                dev_err(&client->dev, "init chip error %d\n", ret);
                return ret;
        }

        /* enable runtime pm with autosuspend delay of 2s */
        pm_runtime_get_noresume(&client->dev);
        pm_runtime_set_active(&client->dev);
        pm_runtime_enable(&client->dev);
        pm_runtime_set_autosuspend_delay(&client->dev, 2000);
        pm_runtime_use_autosuspend(&client->dev);
        pm_runtime_put(&client->dev);
        ret = devm_add_action_or_reset(&client->dev, icp10100_pm_disable,
                                       &client->dev);
        if (ret)
                return ret;

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

static int icp10100_suspend(struct device *dev)
{
        struct icp10100_state *st = iio_priv(dev_get_drvdata(dev));
        int ret;

        mutex_lock(&st->lock);
        ret = regulator_disable(st->vdd);
        mutex_unlock(&st->lock);

        return ret;
}

static int icp10100_resume(struct device *dev)
{
        struct icp10100_state *st = iio_priv(dev_get_drvdata(dev));
        int ret;

        mutex_lock(&st->lock);

        ret = icp10100_enable_regulator(st);
        if (ret)
                goto out_unlock;

        /* reset chip */
        ret = icp10100_send_cmd(st, &icp10100_cmd_soft_reset, NULL, 0);

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

static DEFINE_RUNTIME_DEV_PM_OPS(icp10100_pm, icp10100_suspend, icp10100_resume,
                                 NULL);

static const struct of_device_id icp10100_of_match[] = {
        {
                .compatible = "invensense,icp10100",
        },
        { }
};
MODULE_DEVICE_TABLE(of, icp10100_of_match);

static const struct i2c_device_id icp10100_id[] = {
        { "icp10100" },
        { }
};
MODULE_DEVICE_TABLE(i2c, icp10100_id);

static struct i2c_driver icp10100_driver = {
        .driver = {
                .name = "icp10100",
                .pm = pm_ptr(&icp10100_pm),
                .of_match_table = icp10100_of_match,
        },
        .probe = icp10100_probe,
        .id_table = icp10100_id,
};
module_i2c_driver(icp10100_driver);

MODULE_AUTHOR("InvenSense, Inc.");
MODULE_DESCRIPTION("InvenSense icp10100 driver");
MODULE_LICENSE("GPL");