// 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");