// SPDX-License-Identifier: GPL-2.0-only
/*
 * AL3010 - Dyna Image Ambient Light Sensor
 *
 * Copyright (c) 2014, Intel Corporation.
 * Copyright (c) 2016, Dyna-Image Corp.
 * Copyright (c) 2020, David Heidelberg, Michał Mirosław, Dmitry Osipenko
 *
 * IIO driver for AL3010 (7-bit I2C slave address 0x1C).
 *
 * TODO: interrupt support, thresholds
 * When the driver will get support for interrupt handling, then interrupt
 * will need to be disabled before turning sensor OFF in order to avoid
 * potential races with the interrupt handling.
 */

#include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/mod_devicetable.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define AL3010_REG_SYSTEM               0x00
#define AL3010_REG_DATA_LOW             0x0c
#define AL3010_REG_CONFIG               0x10

#define AL3010_CONFIG_DISABLE           0x00
#define AL3010_CONFIG_ENABLE            0x01

#define AL3010_GAIN_MASK                GENMASK(6,4)

#define AL3010_SCALE_AVAILABLE "1.1872 0.2968 0.0742 0.018"

enum al3xxxx_range {
        AL3XXX_RANGE_1, /* 77806 lx */
        AL3XXX_RANGE_2, /* 19542 lx */
        AL3XXX_RANGE_3, /*  4863 lx */
        AL3XXX_RANGE_4  /*  1216 lx */
};

static const int al3010_scales[][2] = {
        {0, 1187200}, {0, 296800}, {0, 74200}, {0, 18600}
};

static const struct regmap_config al3010_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = AL3010_REG_CONFIG,
};

struct al3010_data {
        struct regmap *regmap;
};

static const struct iio_chan_spec al3010_channels[] = {
        {
                .type   = IIO_LIGHT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                                      BIT(IIO_CHAN_INFO_SCALE),
        }
};

static IIO_CONST_ATTR(in_illuminance_scale_available, AL3010_SCALE_AVAILABLE);

static struct attribute *al3010_attributes[] = {
        &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group al3010_attribute_group = {
        .attrs = al3010_attributes,
};

static int al3010_set_pwr_on(struct al3010_data *data)
{
        return regmap_write(data->regmap, AL3010_REG_SYSTEM, AL3010_CONFIG_ENABLE);
}

static void al3010_set_pwr_off(void *_data)
{
        struct al3010_data *data = _data;
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = regmap_write(data->regmap, AL3010_REG_SYSTEM, AL3010_CONFIG_DISABLE);
        if (ret)
                dev_err(dev, "failed to write system register\n");
}

static int al3010_init(struct al3010_data *data)
{
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = al3010_set_pwr_on(data);
        if (ret)
                return ret;

        ret = devm_add_action_or_reset(dev, al3010_set_pwr_off, data);
        if (ret)
                return ret;
        return regmap_write(data->regmap, AL3010_REG_CONFIG,
                            FIELD_PREP(AL3010_GAIN_MASK, AL3XXX_RANGE_3));
}

static int al3010_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan, int *val,
                           int *val2, long mask)
{
        struct al3010_data *data = iio_priv(indio_dev);
        int ret, gain, raw;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                /*
                 * ALS ADC value is stored in two adjacent registers:
                 * - low byte of output is stored at AL3010_REG_DATA_LOW
                 * - high byte of output is stored at AL3010_REG_DATA_LOW + 1
                 */
                ret = regmap_read(data->regmap, AL3010_REG_DATA_LOW, &raw);
                if (ret)
                        return ret;

                *val = raw;

                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                ret = regmap_read(data->regmap, AL3010_REG_CONFIG, &gain);
                if (ret)
                        return ret;

                gain = FIELD_GET(AL3010_GAIN_MASK, gain);
                *val = al3010_scales[gain][0];
                *val2 = al3010_scales[gain][1];

                return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
}

static int al3010_write_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int val,
                            int val2, long mask)
{
        struct al3010_data *data = iio_priv(indio_dev);
        unsigned int i;

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                for (i = 0; i < ARRAY_SIZE(al3010_scales); i++) {
                        if (val != al3010_scales[i][0] ||
                            val2 != al3010_scales[i][1])
                                continue;

                        return regmap_write(data->regmap, AL3010_REG_CONFIG,
                                            FIELD_PREP(AL3010_GAIN_MASK, i));
                }
                break;
        }
        return -EINVAL;
}

static const struct iio_info al3010_info = {
        .read_raw       = al3010_read_raw,
        .write_raw      = al3010_write_raw,
        .attrs          = &al3010_attribute_group,
};

static int al3010_probe(struct i2c_client *client)
{
        struct al3010_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, &al3010_regmap_config);
        if (IS_ERR(data->regmap))
                return dev_err_probe(dev, PTR_ERR(data->regmap),
                                     "cannot allocate regmap\n");

        indio_dev->info = &al3010_info;
        indio_dev->name = "al3010";
        indio_dev->channels = al3010_channels;
        indio_dev->num_channels = ARRAY_SIZE(al3010_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = al3010_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 al3010_suspend(struct device *dev)
{
        struct al3010_data *data = iio_priv(dev_get_drvdata(dev));

        al3010_set_pwr_off(data);
        return 0;
}

static int al3010_resume(struct device *dev)
{
        struct al3010_data *data = iio_priv(dev_get_drvdata(dev));

        return al3010_set_pwr_on(data);
}

static DEFINE_SIMPLE_DEV_PM_OPS(al3010_pm_ops, al3010_suspend, al3010_resume);

static const struct i2c_device_id al3010_id[] = {
        {"al3010", },
        { }
};
MODULE_DEVICE_TABLE(i2c, al3010_id);

static const struct of_device_id al3010_of_match[] = {
        { .compatible = "dynaimage,al3010", },
        { }
};
MODULE_DEVICE_TABLE(of, al3010_of_match);

static struct i2c_driver al3010_driver = {
        .driver = {
                .name = "al3010",
                .of_match_table = al3010_of_match,
                .pm = pm_sleep_ptr(&al3010_pm_ops),
        },
        .probe          = al3010_probe,
        .id_table       = al3010_id,
};
module_i2c_driver(al3010_driver);

MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
MODULE_AUTHOR("David Heidelberg <david@ixit.cz>");
MODULE_DESCRIPTION("AL3010 Ambient Light Sensor driver");
MODULE_LICENSE("GPL v2");