root/drivers/iio/light/adjd_s311.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * adjd_s311.c - Support for ADJD-S311-CR999 digital color sensor
 *
 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * driver for ADJD-S311-CR999 digital color sensor (10-bit channels for
 * red, green, blue, clear); 7-bit I2C slave address 0x74
 *
 * limitations: no calibration, no offset mode, no sleep mode
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/bitmap.h>
#include <linux/err.h>
#include <linux/irq.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>

#define ADJD_S311_DRV_NAME "adjd_s311"

#define ADJD_S311_CTRL          0x00
#define ADJD_S311_CONFIG        0x01
#define ADJD_S311_CAP_RED       0x06
#define ADJD_S311_CAP_GREEN     0x07
#define ADJD_S311_CAP_BLUE      0x08
#define ADJD_S311_CAP_CLEAR     0x09
#define ADJD_S311_INT_RED       0x0a
#define ADJD_S311_INT_GREEN     0x0c
#define ADJD_S311_INT_BLUE      0x0e
#define ADJD_S311_INT_CLEAR     0x10
#define ADJD_S311_DATA_RED      0x40
#define ADJD_S311_DATA_GREEN    0x42
#define ADJD_S311_DATA_BLUE     0x44
#define ADJD_S311_DATA_CLEAR    0x46
#define ADJD_S311_OFFSET_RED    0x48
#define ADJD_S311_OFFSET_GREEN  0x49
#define ADJD_S311_OFFSET_BLUE   0x4a
#define ADJD_S311_OFFSET_CLEAR  0x4b

#define ADJD_S311_CTRL_GOFS     0x02
#define ADJD_S311_CTRL_GSSR     0x01
#define ADJD_S311_CAP_MASK      0x0f
#define ADJD_S311_INT_MASK      0x0fff
#define ADJD_S311_DATA_MASK     0x03ff

struct adjd_s311_data {
        struct i2c_client *client;
};

enum adjd_s311_channel_idx {
        IDX_RED, IDX_GREEN, IDX_BLUE, IDX_CLEAR
};

#define ADJD_S311_DATA_REG(chan) (ADJD_S311_DATA_RED + (chan) * 2)
#define ADJD_S311_INT_REG(chan) (ADJD_S311_INT_RED + (chan) * 2)
#define ADJD_S311_CAP_REG(chan) (ADJD_S311_CAP_RED + (chan))

static int adjd_s311_req_data(struct iio_dev *indio_dev)
{
        struct adjd_s311_data *data = iio_priv(indio_dev);
        int tries = 10;

        int ret = i2c_smbus_write_byte_data(data->client, ADJD_S311_CTRL,
                ADJD_S311_CTRL_GSSR);
        if (ret < 0)
                return ret;

        while (tries--) {
                ret = i2c_smbus_read_byte_data(data->client, ADJD_S311_CTRL);
                if (ret < 0)
                        return ret;
                if (!(ret & ADJD_S311_CTRL_GSSR))
                        break;
                msleep(20);
        }

        if (tries < 0) {
                dev_err(&data->client->dev,
                        "adjd_s311_req_data() failed, data not ready\n");
                return -EIO;
        }

        return 0;
}

static int adjd_s311_read_data(struct iio_dev *indio_dev, u8 reg, int *val)
{
        struct adjd_s311_data *data = iio_priv(indio_dev);

        int ret = adjd_s311_req_data(indio_dev);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_word_data(data->client, reg);
        if (ret < 0)
                return ret;

        *val = ret & ADJD_S311_DATA_MASK;

        return 0;
}

static irqreturn_t adjd_s311_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct adjd_s311_data *data = iio_priv(indio_dev);
        s64 time_ns = iio_get_time_ns(indio_dev);
        int i, j = 0;
        struct {
                s16 chans[4];
                aligned_s64 ts;
        } scan = { };

        int ret = adjd_s311_req_data(indio_dev);
        if (ret < 0)
                goto done;

        iio_for_each_active_channel(indio_dev, i) {
                ret = i2c_smbus_read_word_data(data->client,
                        ADJD_S311_DATA_REG(i));
                if (ret < 0)
                        goto done;

                scan.chans[j++] = ret & ADJD_S311_DATA_MASK;
        }

        iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan), time_ns);

done:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

#define ADJD_S311_CHANNEL(_color, _scan_idx) { \
        .type = IIO_INTENSITY, \
        .modified = 1, \
        .address = (IDX_##_color), \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
                BIT(IIO_CHAN_INFO_HARDWAREGAIN) | \
                BIT(IIO_CHAN_INFO_INT_TIME), \
        .channel2 = (IIO_MOD_LIGHT_##_color), \
        .scan_index = (_scan_idx), \
        .scan_type = { \
                .sign = 'u', \
                .realbits = 10, \
                .storagebits = 16, \
                .endianness = IIO_CPU, \
        }, \
}

static const struct iio_chan_spec adjd_s311_channels[] = {
        ADJD_S311_CHANNEL(RED, 0),
        ADJD_S311_CHANNEL(GREEN, 1),
        ADJD_S311_CHANNEL(BLUE, 2),
        ADJD_S311_CHANNEL(CLEAR, 3),
        IIO_CHAN_SOFT_TIMESTAMP(4),
};

static int adjd_s311_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val, int *val2, long mask)
{
        struct adjd_s311_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = adjd_s311_read_data(indio_dev,
                        ADJD_S311_DATA_REG(chan->address), val);
                if (ret < 0)
                        return ret;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_HARDWAREGAIN:
                ret = i2c_smbus_read_byte_data(data->client,
                        ADJD_S311_CAP_REG(chan->address));
                if (ret < 0)
                        return ret;
                *val = ret & ADJD_S311_CAP_MASK;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_INT_TIME:
                ret = i2c_smbus_read_word_data(data->client,
                        ADJD_S311_INT_REG(chan->address));
                if (ret < 0)
                        return ret;
                *val = 0;
                /*
                 * not documented, based on measurement:
                 * 4095 LSBs correspond to roughly 4 ms
                 */
                *val2 = ret & ADJD_S311_INT_MASK;
                return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
}

static int adjd_s311_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        struct adjd_s311_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                if (val < 0 || val > ADJD_S311_CAP_MASK)
                        return -EINVAL;

                return i2c_smbus_write_byte_data(data->client,
                        ADJD_S311_CAP_REG(chan->address), val);
        case IIO_CHAN_INFO_INT_TIME:
                if (val != 0 || val2 < 0 || val2 > ADJD_S311_INT_MASK)
                        return -EINVAL;

                return i2c_smbus_write_word_data(data->client,
                        ADJD_S311_INT_REG(chan->address), val2);
        }
        return -EINVAL;
}

static const struct iio_info adjd_s311_info = {
        .read_raw = adjd_s311_read_raw,
        .write_raw = adjd_s311_write_raw,
};

static int adjd_s311_probe(struct i2c_client *client)
{
        struct adjd_s311_data *data;
        struct iio_dev *indio_dev;
        int err;

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

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

        indio_dev->info = &adjd_s311_info;
        indio_dev->name = ADJD_S311_DRV_NAME;
        indio_dev->channels = adjd_s311_channels;
        indio_dev->num_channels = ARRAY_SIZE(adjd_s311_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        err = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
                                              adjd_s311_trigger_handler, NULL);
        if (err < 0)
                return err;

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

static const struct i2c_device_id adjd_s311_id[] = {
        { "adjd_s311" },
        { }
};
MODULE_DEVICE_TABLE(i2c, adjd_s311_id);

static struct i2c_driver adjd_s311_driver = {
        .driver = {
                .name   = ADJD_S311_DRV_NAME,
        },
        .probe          = adjd_s311_probe,
        .id_table       = adjd_s311_id,
};
module_i2c_driver(adjd_s311_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("ADJD-S311 color sensor");
MODULE_LICENSE("GPL");