root/drivers/iio/light/cm3323.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * CM3323 - Capella Color Light Sensor
 *
 * Copyright (c) 2015, Intel Corporation.
 *
 * IIO driver for CM3323 (7-bit I2C slave address 0x10)
 *
 * TODO: calibscale to correct the lens factor
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/mutex.h>

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

#define CM3323_DRV_NAME "cm3323"

#define CM3323_CMD_CONF         0x00
#define CM3323_CMD_RED_DATA     0x08
#define CM3323_CMD_GREEN_DATA   0x09
#define CM3323_CMD_BLUE_DATA    0x0A
#define CM3323_CMD_CLEAR_DATA   0x0B

#define CM3323_CONF_SD_BIT      BIT(0) /* sensor disable */
#define CM3323_CONF_AF_BIT      BIT(1) /* auto/manual force mode */
#define CM3323_CONF_IT_MASK     GENMASK(6, 4)
#define CM3323_CONF_IT_SHIFT    4

#define CM3323_INT_TIME_AVAILABLE "0.04 0.08 0.16 0.32 0.64 1.28"

static const struct {
        int val;
        int val2;
} cm3323_int_time[] = {
        {0, 40000},  /* 40 ms */
        {0, 80000},  /* 80 ms */
        {0, 160000}, /* 160 ms */
        {0, 320000}, /* 320 ms */
        {0, 640000}, /* 640 ms */
        {1, 280000}, /* 1280 ms */
};

struct cm3323_data {
        struct i2c_client *client;
        u16 reg_conf;
        struct mutex mutex;
};

#define CM3323_COLOR_CHANNEL(_color, _addr) { \
        .type = IIO_INTENSITY, \
        .modified = 1, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
        .channel2 = IIO_MOD_LIGHT_##_color, \
        .address = _addr, \
}

static const struct iio_chan_spec cm3323_channels[] = {
        CM3323_COLOR_CHANNEL(RED, CM3323_CMD_RED_DATA),
        CM3323_COLOR_CHANNEL(GREEN, CM3323_CMD_GREEN_DATA),
        CM3323_COLOR_CHANNEL(BLUE, CM3323_CMD_BLUE_DATA),
        CM3323_COLOR_CHANNEL(CLEAR, CM3323_CMD_CLEAR_DATA),
};

static IIO_CONST_ATTR_INT_TIME_AVAIL(CM3323_INT_TIME_AVAILABLE);

static struct attribute *cm3323_attributes[] = {
        &iio_const_attr_integration_time_available.dev_attr.attr,
        NULL
};

static const struct attribute_group cm3323_attribute_group = {
        .attrs = cm3323_attributes,
};

static int cm3323_init(struct iio_dev *indio_dev)
{
        int ret;
        struct cm3323_data *data = iio_priv(indio_dev);

        ret = i2c_smbus_read_word_data(data->client, CM3323_CMD_CONF);
        if (ret < 0) {
                dev_err(&data->client->dev, "Error reading reg_conf\n");
                return ret;
        }

        /* enable sensor and set auto force mode */
        ret &= ~(CM3323_CONF_SD_BIT | CM3323_CONF_AF_BIT);

        ret = i2c_smbus_write_word_data(data->client, CM3323_CMD_CONF, ret);
        if (ret < 0) {
                dev_err(&data->client->dev, "Error writing reg_conf\n");
                return ret;
        }

        data->reg_conf = ret;

        return 0;
}

static void cm3323_disable(void *data)
{
        int ret;
        struct iio_dev *indio_dev = data;
        struct cm3323_data *cm_data = iio_priv(indio_dev);

        ret = i2c_smbus_write_word_data(cm_data->client, CM3323_CMD_CONF,
                                        CM3323_CONF_SD_BIT);
        if (ret < 0)
                dev_err(&cm_data->client->dev, "Error writing reg_conf\n");
}

static int cm3323_set_it_bits(struct cm3323_data *data, int val, int val2)
{
        int i, ret;
        u16 reg_conf;

        for (i = 0; i < ARRAY_SIZE(cm3323_int_time); i++) {
                if (val == cm3323_int_time[i].val &&
                    val2 == cm3323_int_time[i].val2) {
                        reg_conf = data->reg_conf & ~CM3323_CONF_IT_MASK;
                        reg_conf |= i << CM3323_CONF_IT_SHIFT;

                        ret = i2c_smbus_write_word_data(data->client,
                                                        CM3323_CMD_CONF,
                                                        reg_conf);
                        if (ret < 0)
                                return ret;

                        data->reg_conf = reg_conf;

                        return 0;
                }
        }

        return -EINVAL;
}

static int cm3323_get_it_bits(struct cm3323_data *data)
{
        int bits;

        bits = (data->reg_conf & CM3323_CONF_IT_MASK) >>
                CM3323_CONF_IT_SHIFT;

        if (bits >= ARRAY_SIZE(cm3323_int_time))
                return -EINVAL;

        return bits;
}

static int cm3323_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan, int *val,
                           int *val2, long mask)
{
        int ret;
        struct cm3323_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                mutex_lock(&data->mutex);
                ret = i2c_smbus_read_word_data(data->client, chan->address);
                if (ret < 0) {
                        mutex_unlock(&data->mutex);
                        return ret;
                }
                *val = ret;
                mutex_unlock(&data->mutex);

                return IIO_VAL_INT;
        case IIO_CHAN_INFO_INT_TIME:
                mutex_lock(&data->mutex);
                ret = cm3323_get_it_bits(data);
                if (ret < 0) {
                        mutex_unlock(&data->mutex);
                        return ret;
                }

                *val = cm3323_int_time[ret].val;
                *val2 = cm3323_int_time[ret].val2;
                mutex_unlock(&data->mutex);

                return IIO_VAL_INT_PLUS_MICRO;
        default:
                return -EINVAL;
        }
}

static int cm3323_write_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int val,
                            int val2, long mask)
{
        struct cm3323_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_INT_TIME:
                mutex_lock(&data->mutex);
                ret = cm3323_set_it_bits(data, val, val2);
                mutex_unlock(&data->mutex);

                return ret;
        default:
                return -EINVAL;
        }
}

static const struct iio_info cm3323_info = {
        .read_raw       = cm3323_read_raw,
        .write_raw      = cm3323_write_raw,
        .attrs          = &cm3323_attribute_group,
};

static int cm3323_probe(struct i2c_client *client)
{
        struct cm3323_data *data;
        struct iio_dev *indio_dev;
        int ret;

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

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

        mutex_init(&data->mutex);

        indio_dev->info = &cm3323_info;
        indio_dev->name = CM3323_DRV_NAME;
        indio_dev->channels = cm3323_channels;
        indio_dev->num_channels = ARRAY_SIZE(cm3323_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = cm3323_init(indio_dev);
        if (ret < 0) {
                dev_err(&client->dev, "cm3323 chip init failed\n");
                return ret;
        }

        ret = devm_add_action_or_reset(&client->dev, cm3323_disable, indio_dev);
        if (ret < 0)
                return ret;

        return devm_iio_device_register(&client->dev, indio_dev);
}

static const struct i2c_device_id cm3323_id[] = {
        { "cm3323" },
        { }
};
MODULE_DEVICE_TABLE(i2c, cm3323_id);

static const struct of_device_id cm3323_of_match[] = {
        { .compatible = "capella,cm3323", },
        { }
};
MODULE_DEVICE_TABLE(of, cm3323_of_match);

static struct i2c_driver cm3323_driver = {
        .driver = {
                .name = CM3323_DRV_NAME,
                .of_match_table = cm3323_of_match,
        },
        .probe          = cm3323_probe,
        .id_table       = cm3323_id,
};

module_i2c_driver(cm3323_driver);

MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("Capella CM3323 Color Light Sensor driver");
MODULE_LICENSE("GPL v2");