// SPDX-License-Identifier: GPL-2.0-only
/*
 * AL3320A - Dyna Image Ambient Light Sensor
 *
 * Copyright (c) 2014, Intel Corporation.
 *
 * IIO driver for AL3320A (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 AL3320A_REG_CONFIG              0x00
#define AL3320A_REG_STATUS              0x01
#define AL3320A_REG_INT                 0x02
#define AL3320A_REG_WAIT                0x06
#define AL3320A_REG_CONFIG_RANGE        0x07
#define AL3320A_REG_PERSIST             0x08
#define AL3320A_REG_MEAN_TIME           0x09
#define AL3320A_REG_ADUMMY              0x0A
#define AL3320A_REG_DATA_LOW            0x22

#define AL3320A_REG_LOW_THRESH_LOW      0x30
#define AL3320A_REG_LOW_THRESH_HIGH     0x31
#define AL3320A_REG_HIGH_THRESH_LOW     0x32
#define AL3320A_REG_HIGH_THRESH_HIGH    0x33

#define AL3320A_CONFIG_DISABLE          0x00
#define AL3320A_CONFIG_ENABLE           0x01

#define AL3320A_GAIN_MASK               GENMASK(2, 1)

/* chip params default values */
#define AL3320A_DEFAULT_MEAN_TIME       4
#define AL3320A_DEFAULT_WAIT_TIME       0 /* no waiting */

#define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"

enum al3320a_range {
        AL3320A_RANGE_1, /* 33.28 Klx */
        AL3320A_RANGE_2, /* 8.32 Klx  */
        AL3320A_RANGE_3, /* 2.08 Klx  */
        AL3320A_RANGE_4  /* 0.65 Klx  */
};

static const int al3320a_scales[][2] = {
        {0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
};

static const struct regmap_config al3320a_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = AL3320A_REG_HIGH_THRESH_HIGH,
};

struct al3320a_data {
        struct regmap *regmap;
};

static const struct iio_chan_spec al3320a_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, AL3320A_SCALE_AVAILABLE);

static struct attribute *al3320a_attributes[] = {
        &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group al3320a_attribute_group = {
        .attrs = al3320a_attributes,
};

static int al3320a_set_pwr_on(struct al3320a_data *data)
{
        return regmap_write(data->regmap, AL3320A_REG_CONFIG, AL3320A_CONFIG_ENABLE);
}

static void al3320a_set_pwr_off(void *_data)
{
        struct al3320a_data *data = _data;
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = regmap_write(data->regmap, AL3320A_REG_CONFIG, AL3320A_CONFIG_DISABLE);
        if (ret)
                dev_err(dev, "failed to write system register\n");
}

static int al3320a_init(struct al3320a_data *data)
{
        struct device *dev = regmap_get_device(data->regmap);
        int ret;

        ret = al3320a_set_pwr_on(data);
        if (ret)
                return ret;

        ret = devm_add_action_or_reset(dev, al3320a_set_pwr_off, data);
        if (ret)
                return ret;

        ret = regmap_write(data->regmap, AL3320A_REG_CONFIG_RANGE,
                           FIELD_PREP(AL3320A_GAIN_MASK, AL3320A_RANGE_3));
        if (ret)
                return ret;

        ret = regmap_write(data->regmap, AL3320A_REG_MEAN_TIME,
                           AL3320A_DEFAULT_MEAN_TIME);
        if (ret)
                return ret;

        return regmap_write(data->regmap, AL3320A_REG_WAIT,
                            AL3320A_DEFAULT_WAIT_TIME);
}

static int al3320a_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int *val,
                            int *val2, long mask)
{
        struct al3320a_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 AL3320A_REG_DATA_LOW
                 * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
                 */
                ret = regmap_read(data->regmap, AL3320A_REG_DATA_LOW, &raw);
                if (ret)
                        return ret;

                *val = raw;

                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                ret = regmap_read(data->regmap, AL3320A_REG_CONFIG_RANGE, &gain);
                if (ret)
                        return ret;

                gain = FIELD_GET(AL3320A_GAIN_MASK, gain);
                *val = al3320a_scales[gain][0];
                *val2 = al3320a_scales[gain][1];

                return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
}

static int al3320a_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan, int val,
                             int val2, long mask)
{
        struct al3320a_data *data = iio_priv(indio_dev);
        unsigned int i;

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
                        if (val != al3320a_scales[i][0] ||
                            val2 != al3320a_scales[i][1])
                                continue;

                        return regmap_write(data->regmap, AL3320A_REG_CONFIG_RANGE,
                                            FIELD_PREP(AL3320A_GAIN_MASK, i));
                }
                break;
        }
        return -EINVAL;
}

static const struct iio_info al3320a_info = {
        .read_raw       = al3320a_read_raw,
        .write_raw      = al3320a_write_raw,
        .attrs          = &al3320a_attribute_group,
};

static int al3320a_probe(struct i2c_client *client)
{
        struct al3320a_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, &al3320a_regmap_config);
        if (IS_ERR(data->regmap))
                return dev_err_probe(dev, PTR_ERR(data->regmap),
                                     "cannot allocate regmap\n");

        indio_dev->info = &al3320a_info;
        indio_dev->name = "al3320a";
        indio_dev->channels = al3320a_channels;
        indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = al3320a_init(data);
        if (ret < 0) {
                dev_err(dev, "al3320a chip init failed\n");
                return ret;
        }

        return devm_iio_device_register(dev, indio_dev);
}

static int al3320a_suspend(struct device *dev)
{
        struct al3320a_data *data = iio_priv(dev_get_drvdata(dev));

        al3320a_set_pwr_off(data);
        return 0;
}

static int al3320a_resume(struct device *dev)
{
        struct al3320a_data *data = iio_priv(dev_get_drvdata(dev));

        return al3320a_set_pwr_on(data);
}

static DEFINE_SIMPLE_DEV_PM_OPS(al3320a_pm_ops, al3320a_suspend,
                                al3320a_resume);

static const struct i2c_device_id al3320a_id[] = {
        { "al3320a" },
        { }
};
MODULE_DEVICE_TABLE(i2c, al3320a_id);

static const struct of_device_id al3320a_of_match[] = {
        { .compatible = "dynaimage,al3320a", },
        { }
};
MODULE_DEVICE_TABLE(of, al3320a_of_match);

static const struct acpi_device_id al3320a_acpi_match[] = {
        {"CALS0001"},
        { }
};
MODULE_DEVICE_TABLE(acpi, al3320a_acpi_match);

static struct i2c_driver al3320a_driver = {
        .driver = {
                .name = "al3320a",
                .of_match_table = al3320a_of_match,
                .pm = pm_sleep_ptr(&al3320a_pm_ops),
                .acpi_match_table = al3320a_acpi_match,
        },
        .probe          = al3320a_probe,
        .id_table       = al3320a_id,
};

module_i2c_driver(al3320a_driver);

MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
MODULE_LICENSE("GPL v2");