// SPDX-License-Identifier: GPL-2.0-only
#include <linux/array_size.h>
#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/types.h>

#include <linux/iio/iio.h>

#define AL3000A_REG_SYSTEM              0x00
#define AL3000A_REG_DATA                0x05

#define AL3000A_CONFIG_ENABLE           0x00
#define AL3000A_CONFIG_DISABLE          0x0b
#define AL3000A_CONFIG_RESET            0x0f
#define AL3000A_GAIN_MASK               GENMASK(5, 0)

/*
 * These are pre-calculated lux values based on possible output of sensor
 * (range 0x00 - 0x3F)
 */
static const u32 lux_table[] = {
        1, 1, 1, 2, 2, 2, 3, 4,                                 /* 0 - 7 */
        4, 5, 6, 7, 9, 11, 13, 16,                              /* 8 - 15 */
        19, 22, 27, 32, 39, 46, 56, 67,                         /* 16 - 23 */
        80, 96, 116, 139, 167, 200, 240, 289,                   /* 24 - 31 */
        347, 416, 499, 600, 720, 864, 1037, 1245,               /* 32 - 39 */
        1495, 1795, 2155, 2587, 3105, 3728, 4475, 5373,         /* 40 - 47 */
        6450, 7743, 9296, 11160, 13397, 16084, 19309, 23180,    /* 48 - 55 */
        27828, 33408, 40107, 48148, 57803, 69393, 83306, 100000 /* 56 - 63 */
};

static const struct regmap_config al3000a_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = AL3000A_REG_DATA,
};

struct al3000a_data {
        struct regmap *regmap;
        struct regulator *vdd_supply;
};

static const struct iio_chan_spec al3000a_channels[] = {
        {
                .type = IIO_LIGHT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
        },
};

static int al3000a_set_pwr_on(struct al3000a_data *data)
{
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = regulator_enable(data->vdd_supply);
        if (ret) {
                dev_err(dev, "failed to enable vdd power supply\n");
                return ret;
        }

        return regmap_write(data->regmap, AL3000A_REG_SYSTEM, AL3000A_CONFIG_ENABLE);
}

static void al3000a_set_pwr_off(void *_data)
{
        struct al3000a_data *data = _data;
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = regmap_write(data->regmap, AL3000A_REG_SYSTEM, AL3000A_CONFIG_DISABLE);
        if (ret)
                dev_err(dev, "failed to write system register\n");

        ret = regulator_disable(data->vdd_supply);
        if (ret)
                dev_err(dev, "failed to disable vdd power supply\n");
}

static int al3000a_init(struct al3000a_data *data)
{
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = al3000a_set_pwr_on(data);
        if (ret)
                return ret;

        ret = devm_add_action_or_reset(dev, al3000a_set_pwr_off, data);
        if (ret)
                return ret;

        ret = regmap_write(data->regmap, AL3000A_REG_SYSTEM, AL3000A_CONFIG_RESET);
        if (ret)
                return ret;

        return regmap_write(data->regmap, AL3000A_REG_SYSTEM, AL3000A_CONFIG_ENABLE);
}

static int al3000a_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int *val,
                            int *val2, long mask)
{
        struct al3000a_data *data = iio_priv(indio_dev);
        int ret, gain;

        switch (mask) {
        case IIO_CHAN_INFO_PROCESSED:
                ret = regmap_read(data->regmap, AL3000A_REG_DATA, &gain);
                if (ret)
                        return ret;

                *val = lux_table[gain & AL3000A_GAIN_MASK];

                return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
}

static const struct iio_info al3000a_info = {
        .read_raw = al3000a_read_raw,
};

static int al3000a_probe(struct i2c_client *client)
{
        struct al3000a_data *data;
        struct device *dev = &client->dev;
        struct iio_dev *indio_dev;
        int ret;

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

        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);

        data->regmap = devm_regmap_init_i2c(client, &al3000a_regmap_config);
        if (IS_ERR(data->regmap))
                return dev_err_probe(dev, PTR_ERR(data->regmap),
                                     "cannot allocate regmap\n");

        data->vdd_supply = devm_regulator_get(dev, "vdd");
        if (IS_ERR(data->vdd_supply))
                return dev_err_probe(dev, PTR_ERR(data->vdd_supply),
                                     "failed to get vdd regulator\n");

        indio_dev->info = &al3000a_info;
        indio_dev->name = "al3000a";
        indio_dev->channels = al3000a_channels;
        indio_dev->num_channels = ARRAY_SIZE(al3000a_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = al3000a_init(data);
        if (ret)
                return dev_err_probe(dev, ret, "failed to init ALS\n");

        return devm_iio_device_register(dev, indio_dev);
}

static int al3000a_suspend(struct device *dev)
{
        struct al3000a_data *data = iio_priv(dev_get_drvdata(dev));

        al3000a_set_pwr_off(data);
        return 0;
}

static int al3000a_resume(struct device *dev)
{
        struct al3000a_data *data = iio_priv(dev_get_drvdata(dev));

        return al3000a_set_pwr_on(data);
}

static DEFINE_SIMPLE_DEV_PM_OPS(al3000a_pm_ops, al3000a_suspend, al3000a_resume);

static const struct i2c_device_id al3000a_id[] = {
        { "al3000a" },
        { }
};
MODULE_DEVICE_TABLE(i2c, al3000a_id);

static const struct of_device_id al3000a_of_match[] = {
        { .compatible = "dynaimage,al3000a" },
        { }
};
MODULE_DEVICE_TABLE(of, al3000a_of_match);

static struct i2c_driver al3000a_driver = {
        .driver = {
                .name = "al3000a",
                .of_match_table = al3000a_of_match,
                .pm = pm_sleep_ptr(&al3000a_pm_ops),
        },
        .probe = al3000a_probe,
        .id_table = al3000a_id,
};
module_i2c_driver(al3000a_driver);

MODULE_AUTHOR("Svyatolsav Ryhel <clamor95@gmail.com>");
MODULE_DESCRIPTION("al3000a Ambient Light Sensor driver");
MODULE_LICENSE("GPL");