// SPDX-License-Identifier: GPL-2.0-only
/*
 * CM3232 Ambient Light Sensor
 *
 * Copyright (C) 2014-2015 Capella Microsystems Inc.
 * Author: Kevin Tsai <ktsai@capellamicro.com>
 *
 * IIO driver for CM3232 (7-bit I2C slave address 0x10).
 */

#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/init.h>

/* Registers Address */
#define CM3232_REG_ADDR_CMD             0x00
#define CM3232_REG_ADDR_ALS             0x50
#define CM3232_REG_ADDR_ID              0x53

#define CM3232_CMD_ALS_DISABLE          BIT(0)

#define CM3232_CMD_ALS_IT_SHIFT         2
#define CM3232_CMD_ALS_IT_MASK          (BIT(2) | BIT(3) | BIT(4))
#define CM3232_CMD_ALS_IT_DEFAULT       (0x01 << CM3232_CMD_ALS_IT_SHIFT)

#define CM3232_CMD_ALS_RESET            BIT(6)

#define CM3232_CMD_DEFAULT              CM3232_CMD_ALS_IT_DEFAULT

#define CM3232_HW_ID                    0x32
#define CM3232_CALIBSCALE_DEFAULT       100000
#define CM3232_CALIBSCALE_RESOLUTION    100000
#define CM3232_MLUX_PER_LUX             1000

#define CM3232_MLUX_PER_BIT_DEFAULT     64
#define CM3232_MLUX_PER_BIT_BASE_IT     100000

static const struct {
        int val;
        int val2;
        u8 it;
} cm3232_als_it_scales[] = {
        {0, 100000, 0}, /* 0.100000 */
        {0, 200000, 1}, /* 0.200000 */
        {0, 400000, 2}, /* 0.400000 */
        {0, 800000, 3}, /* 0.800000 */
        {1, 600000, 4}, /* 1.600000 */
        {3, 200000, 5}, /* 3.200000 */
};

struct cm3232_als_info {
        u8 regs_cmd_default;
        u8 hw_id;
        int mlux_per_bit;
        int mlux_per_bit_base_it;
};

static const struct cm3232_als_info cm3232_als_info_default = {
        .regs_cmd_default = CM3232_CMD_DEFAULT,
        .hw_id = CM3232_HW_ID,
        .mlux_per_bit = CM3232_MLUX_PER_BIT_DEFAULT,
        .mlux_per_bit_base_it = CM3232_MLUX_PER_BIT_BASE_IT,
};

struct cm3232_chip {
        struct i2c_client *client;
        const struct cm3232_als_info *als_info;
        int calibscale;
        u8 regs_cmd;
        u16 regs_als;
};

/**
 * cm3232_reg_init() - Initialize CM3232
 * @chip:       pointer of struct cm3232_chip.
 *
 * Check and initialize CM3232 ambient light sensor.
 *
 * Return: 0 for success; otherwise for error code.
 */
static int cm3232_reg_init(struct cm3232_chip *chip)
{
        struct i2c_client *client = chip->client;
        s32 ret;

        chip->als_info = &cm3232_als_info_default;

        /* Disable and reset device */
        chip->regs_cmd = CM3232_CMD_ALS_DISABLE | CM3232_CMD_ALS_RESET;
        ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
                                        chip->regs_cmd);
        if (ret < 0) {
                dev_err(&chip->client->dev, "Error writing reg_cmd\n");
                return ret;
        }

        /* Identify device */
        ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ID);
        if (ret < 0) {
                dev_err(&chip->client->dev, "Error reading addr_id\n");
                return ret;
        }

        if ((ret & 0xFF) != chip->als_info->hw_id)
                return -ENODEV;

        /* Register default value */
        chip->regs_cmd = chip->als_info->regs_cmd_default;

        /* Configure register */
        ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
                                        chip->regs_cmd);
        if (ret < 0)
                dev_err(&chip->client->dev, "Error writing reg_cmd\n");

        return ret;
}

/**
 *  cm3232_read_als_it() - Get sensor integration time
 *  @chip:      pointer of struct cm3232_chip
 *  @val:       pointer of int to load the integration (sec).
 *  @val2:      pointer of int to load the integration time (microsecond).
 *
 *  Report the current integration time.
 *
 *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
 */
static int cm3232_read_als_it(struct cm3232_chip *chip, int *val, int *val2)
{
        u16 als_it;
        int i;

        als_it = chip->regs_cmd;
        als_it &= CM3232_CMD_ALS_IT_MASK;
        als_it >>= CM3232_CMD_ALS_IT_SHIFT;
        for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
                if (als_it == cm3232_als_it_scales[i].it) {
                        *val = cm3232_als_it_scales[i].val;
                        *val2 = cm3232_als_it_scales[i].val2;
                        return IIO_VAL_INT_PLUS_MICRO;
                }
        }

        return -EINVAL;
}

/**
 * cm3232_write_als_it() - Write sensor integration time
 * @chip:       pointer of struct cm3232_chip.
 * @val:        integration time in second.
 * @val2:       integration time in microsecond.
 *
 * Convert integration time to sensor value.
 *
 * Return: i2c_smbus_write_byte_data command return value.
 */
static int cm3232_write_als_it(struct cm3232_chip *chip, int val, int val2)
{
        struct i2c_client *client = chip->client;
        u16 als_it, cmd;
        int i;
        s32 ret;

        for (i = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++) {
                if (val == cm3232_als_it_scales[i].val &&
                        val2 == cm3232_als_it_scales[i].val2) {

                        als_it = cm3232_als_it_scales[i].it;
                        als_it <<= CM3232_CMD_ALS_IT_SHIFT;

                        cmd = chip->regs_cmd & ~CM3232_CMD_ALS_IT_MASK;
                        cmd |= als_it;
                        ret = i2c_smbus_write_byte_data(client,
                                                        CM3232_REG_ADDR_CMD,
                                                        cmd);
                        if (ret < 0)
                                return ret;
                        chip->regs_cmd = cmd;
                        return 0;
                }
        }
        return -EINVAL;
}

/**
 * cm3232_get_lux() - report current lux value
 * @chip:       pointer of struct cm3232_chip.
 *
 * Convert sensor data to lux.  It depends on integration
 * time and calibscale variable.
 *
 * Return: Zero or positive value is lux, otherwise error code.
 */
static int cm3232_get_lux(struct cm3232_chip *chip)
{
        struct i2c_client *client = chip->client;
        const struct cm3232_als_info *als_info = chip->als_info;
        int ret;
        int val, val2;
        int als_it;
        u64 lux;

        /* Calculate mlux per bit based on als_it */
        ret = cm3232_read_als_it(chip, &val, &val2);
        if (ret < 0)
                return -EINVAL;
        als_it = val * 1000000 + val2;
        lux = (__force u64)als_info->mlux_per_bit;
        lux *= als_info->mlux_per_bit_base_it;
        lux = div_u64(lux, als_it);

        ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ALS);
        if (ret < 0) {
                dev_err(&client->dev, "Error reading reg_addr_als\n");
                return ret;
        }

        chip->regs_als = (u16)ret;
        lux *= chip->regs_als;
        lux *= chip->calibscale;
        lux = div_u64(lux, CM3232_CALIBSCALE_RESOLUTION);
        lux = div_u64(lux, CM3232_MLUX_PER_LUX);

        if (lux > 0xFFFF)
                lux = 0xFFFF;

        return (int)lux;
}

static int cm3232_read_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int *val, int *val2, long mask)
{
        struct cm3232_chip *chip = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_PROCESSED:
                ret = cm3232_get_lux(chip);
                if (ret < 0)
                        return ret;
                *val = ret;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_CALIBSCALE:
                *val = chip->calibscale;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_INT_TIME:
                return cm3232_read_als_it(chip, val, val2);
        }

        return -EINVAL;
}

static int cm3232_write_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int val, int val2, long mask)
{
        struct cm3232_chip *chip = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_CALIBSCALE:
                chip->calibscale = val;
                return 0;
        case IIO_CHAN_INFO_INT_TIME:
                return cm3232_write_als_it(chip, val, val2);
        }

        return -EINVAL;
}

/**
 * cm3232_get_it_available() - Get available ALS IT value
 * @dev:        pointer of struct device.
 * @attr:       pointer of struct device_attribute.
 * @buf:        pointer of return string buffer.
 *
 * Display the available integration time in second.
 *
 * Return: string length.
 */
static ssize_t cm3232_get_it_available(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        int i, len;

        for (i = 0, len = 0; i < ARRAY_SIZE(cm3232_als_it_scales); i++)
                len += scnprintf(buf + len, PAGE_SIZE - len, "%u.%06u ",
                        cm3232_als_it_scales[i].val,
                        cm3232_als_it_scales[i].val2);
        return len + scnprintf(buf + len, PAGE_SIZE - len, "\n");
}

static const struct iio_chan_spec cm3232_channels[] = {
        {
                .type = IIO_LIGHT,
                .info_mask_separate =
                        BIT(IIO_CHAN_INFO_PROCESSED) |
                        BIT(IIO_CHAN_INFO_CALIBSCALE) |
                        BIT(IIO_CHAN_INFO_INT_TIME),
        }
};

static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
                        S_IRUGO, cm3232_get_it_available, NULL, 0);

static struct attribute *cm3232_attributes[] = {
        &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group cm3232_attribute_group = {
        .attrs = cm3232_attributes
};

static const struct iio_info cm3232_info = {
        .read_raw               = &cm3232_read_raw,
        .write_raw              = &cm3232_write_raw,
        .attrs                  = &cm3232_attribute_group,
};

static int cm3232_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct cm3232_chip *chip;
        struct iio_dev *indio_dev;
        int ret;

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

        chip = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        chip->client = client;
        chip->calibscale = CM3232_CALIBSCALE_DEFAULT;

        indio_dev->channels = cm3232_channels;
        indio_dev->num_channels = ARRAY_SIZE(cm3232_channels);
        indio_dev->info = &cm3232_info;
        indio_dev->name = id->name;
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = cm3232_reg_init(chip);
        if (ret) {
                dev_err(&client->dev,
                        "%s: register init failed\n",
                        __func__);
                return ret;
        }

        return iio_device_register(indio_dev);
}

static void cm3232_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);

        i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
                CM3232_CMD_ALS_DISABLE);

        iio_device_unregister(indio_dev);
}

static const struct i2c_device_id cm3232_id[] = {
        { .name = "cm3232" },
        { }
};
MODULE_DEVICE_TABLE(i2c, cm3232_id);

static int cm3232_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct cm3232_chip *chip = iio_priv(indio_dev);
        struct i2c_client *client = chip->client;
        int ret;

        chip->regs_cmd |= CM3232_CMD_ALS_DISABLE;
        ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
                                        chip->regs_cmd);

        return ret;
}

static int cm3232_resume(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct cm3232_chip *chip = iio_priv(indio_dev);
        struct i2c_client *client = chip->client;
        int ret;

        chip->regs_cmd &= ~CM3232_CMD_ALS_DISABLE;
        ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD,
                                        chip->regs_cmd | CM3232_CMD_ALS_RESET);

        return ret;
}

static DEFINE_SIMPLE_DEV_PM_OPS(cm3232_pm_ops, cm3232_suspend, cm3232_resume);

static const struct of_device_id cm3232_of_match[] = {
        {.compatible = "capella,cm3232"},
        { }
};
MODULE_DEVICE_TABLE(of, cm3232_of_match);

static struct i2c_driver cm3232_driver = {
        .driver = {
                .name   = "cm3232",
                .of_match_table = cm3232_of_match,
                .pm     = pm_sleep_ptr(&cm3232_pm_ops),
        },
        .id_table       = cm3232_id,
        .probe          = cm3232_probe,
        .remove         = cm3232_remove,
};

module_i2c_driver(cm3232_driver);

MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
MODULE_DESCRIPTION("CM3232 ambient light sensor driver");
MODULE_LICENSE("GPL");