root/drivers/iio/light/tcs3472.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * tcs3472.c - Support for TAOS TCS3472 color light-to-digital converter
 *
 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * Color light sensor with 16-bit channels for red, green, blue, clear);
 * 7-bit I2C slave address 0x39 (TCS34721, TCS34723) or 0x29 (TCS34725,
 * TCS34727)
 *
 * Datasheet: http://ams.com/eng/content/download/319364/1117183/file/TCS3472_Datasheet_EN_v2.pdf
 *
 * TODO: wait time
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/pm.h>

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

#define TCS3472_DRV_NAME "tcs3472"

#define TCS3472_COMMAND BIT(7)
#define TCS3472_AUTO_INCR BIT(5)
#define TCS3472_SPECIAL_FUNC (BIT(5) | BIT(6))

#define TCS3472_INTR_CLEAR (TCS3472_COMMAND | TCS3472_SPECIAL_FUNC | 0x06)

#define TCS3472_ENABLE (TCS3472_COMMAND | 0x00)
#define TCS3472_ATIME (TCS3472_COMMAND | 0x01)
#define TCS3472_WTIME (TCS3472_COMMAND | 0x03)
#define TCS3472_AILT (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x04)
#define TCS3472_AIHT (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x06)
#define TCS3472_PERS (TCS3472_COMMAND | 0x0c)
#define TCS3472_CONFIG (TCS3472_COMMAND | 0x0d)
#define TCS3472_CONTROL (TCS3472_COMMAND | 0x0f)
#define TCS3472_ID (TCS3472_COMMAND | 0x12)
#define TCS3472_STATUS (TCS3472_COMMAND | 0x13)
#define TCS3472_CDATA (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x14)
#define TCS3472_RDATA (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x16)
#define TCS3472_GDATA (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x18)
#define TCS3472_BDATA (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x1a)

#define TCS3472_STATUS_AINT BIT(4)
#define TCS3472_STATUS_AVALID BIT(0)
#define TCS3472_ENABLE_AIEN BIT(4)
#define TCS3472_ENABLE_AEN BIT(1)
#define TCS3472_ENABLE_PON BIT(0)
#define TCS3472_CONTROL_AGAIN_MASK (BIT(0) | BIT(1))

struct tcs3472_data {
        struct i2c_client *client;
        struct mutex lock;
        u16 low_thresh;
        u16 high_thresh;
        u8 enable;
        u8 control;
        u8 atime;
        u8 apers;
};

static const struct iio_event_spec tcs3472_events[] = {
        {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_RISING,
                .mask_separate = BIT(IIO_EV_INFO_VALUE),
        }, {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_FALLING,
                .mask_separate = BIT(IIO_EV_INFO_VALUE),
        }, {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_EITHER,
                .mask_separate = BIT(IIO_EV_INFO_ENABLE) |
                                 BIT(IIO_EV_INFO_PERIOD),
        },
};

#define TCS3472_CHANNEL(_color, _si, _addr) { \
        .type = IIO_INTENSITY, \
        .modified = 1, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBSCALE) | \
                BIT(IIO_CHAN_INFO_INT_TIME), \
        .channel2 = IIO_MOD_LIGHT_##_color, \
        .address = _addr, \
        .scan_index = _si, \
        .scan_type = { \
                .sign = 'u', \
                .realbits = 16, \
                .storagebits = 16, \
                .endianness = IIO_CPU, \
        }, \
        .event_spec = _si ? NULL : tcs3472_events, \
        .num_event_specs = _si ? 0 : ARRAY_SIZE(tcs3472_events), \
}

static const int tcs3472_agains[] = { 1, 4, 16, 60 };

static const struct iio_chan_spec tcs3472_channels[] = {
        TCS3472_CHANNEL(CLEAR, 0, TCS3472_CDATA),
        TCS3472_CHANNEL(RED, 1, TCS3472_RDATA),
        TCS3472_CHANNEL(GREEN, 2, TCS3472_GDATA),
        TCS3472_CHANNEL(BLUE, 3, TCS3472_BDATA),
        IIO_CHAN_SOFT_TIMESTAMP(4),
};

static int tcs3472_req_data(struct tcs3472_data *data)
{
        int tries = 50;
        int ret;

        while (tries--) {
                ret = i2c_smbus_read_byte_data(data->client, TCS3472_STATUS);
                if (ret < 0)
                        return ret;
                if (ret & TCS3472_STATUS_AVALID)
                        break;
                msleep(20);
        }

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

        return 0;
}

static int tcs3472_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val, int *val2, long mask)
{
        struct tcs3472_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                ret = tcs3472_req_data(data);
                if (ret < 0) {
                        iio_device_release_direct(indio_dev);
                        return ret;
                }
                ret = i2c_smbus_read_word_data(data->client, chan->address);
                iio_device_release_direct(indio_dev);
                if (ret < 0)
                        return ret;
                *val = ret;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_CALIBSCALE:
                *val = tcs3472_agains[data->control &
                        TCS3472_CONTROL_AGAIN_MASK];
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_INT_TIME:
                *val = 0;
                *val2 = (256 - data->atime) * 2400;
                return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
}

static int tcs3472_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        struct tcs3472_data *data = iio_priv(indio_dev);
        int i;

        switch (mask) {
        case IIO_CHAN_INFO_CALIBSCALE:
                if (val2 != 0)
                        return -EINVAL;
                for (i = 0; i < ARRAY_SIZE(tcs3472_agains); i++) {
                        if (val == tcs3472_agains[i]) {
                                data->control &= ~TCS3472_CONTROL_AGAIN_MASK;
                                data->control |= i;
                                return i2c_smbus_write_byte_data(
                                        data->client, TCS3472_CONTROL,
                                        data->control);
                        }
                }
                return -EINVAL;
        case IIO_CHAN_INFO_INT_TIME:
                if (val != 0)
                        return -EINVAL;
                for (i = 0; i < 256; i++) {
                        if (val2 == (256 - i) * 2400) {
                                data->atime = i;
                                return i2c_smbus_write_byte_data(
                                        data->client, TCS3472_ATIME,
                                        data->atime);
                        }

                }
                return -EINVAL;
        }
        return -EINVAL;
}

/*
 * Translation from APERS field value to the number of consecutive out-of-range
 * clear channel values before an interrupt is generated
 */
static const int tcs3472_intr_pers[] = {
        0, 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60
};

static int tcs3472_read_event(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir, enum iio_event_info info, int *val,
        int *val2)
{
        struct tcs3472_data *data = iio_priv(indio_dev);
        int ret;
        unsigned int period;

        mutex_lock(&data->lock);

        switch (info) {
        case IIO_EV_INFO_VALUE:
                *val = (dir == IIO_EV_DIR_RISING) ?
                        data->high_thresh : data->low_thresh;
                ret = IIO_VAL_INT;
                break;
        case IIO_EV_INFO_PERIOD:
                period = (256 - data->atime) * 2400 *
                        tcs3472_intr_pers[data->apers];
                *val = period / USEC_PER_SEC;
                *val2 = period % USEC_PER_SEC;
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        mutex_unlock(&data->lock);

        return ret;
}

static int tcs3472_write_event(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir, enum iio_event_info info, int val,
        int val2)
{
        struct tcs3472_data *data = iio_priv(indio_dev);
        int ret;
        u8 command;
        int period;
        int i;

        mutex_lock(&data->lock);
        switch (info) {
        case IIO_EV_INFO_VALUE:
                switch (dir) {
                case IIO_EV_DIR_RISING:
                        command = TCS3472_AIHT;
                        break;
                case IIO_EV_DIR_FALLING:
                        command = TCS3472_AILT;
                        break;
                default:
                        ret = -EINVAL;
                        goto error;
                }
                ret = i2c_smbus_write_word_data(data->client, command, val);
                if (ret)
                        goto error;

                if (dir == IIO_EV_DIR_RISING)
                        data->high_thresh = val;
                else
                        data->low_thresh = val;
                break;
        case IIO_EV_INFO_PERIOD:
                period = val * USEC_PER_SEC + val2;
                for (i = 1; i < ARRAY_SIZE(tcs3472_intr_pers) - 1; i++) {
                        if (period <= (256 - data->atime) * 2400 *
                                        tcs3472_intr_pers[i])
                                break;
                }
                ret = i2c_smbus_write_byte_data(data->client, TCS3472_PERS, i);
                if (ret)
                        goto error;

                data->apers = i;
                break;
        default:
                ret = -EINVAL;
                break;
        }
error:
        mutex_unlock(&data->lock);

        return ret;
}

static int tcs3472_read_event_config(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir)
{
        struct tcs3472_data *data = iio_priv(indio_dev);
        int ret;

        mutex_lock(&data->lock);
        ret = !!(data->enable & TCS3472_ENABLE_AIEN);
        mutex_unlock(&data->lock);

        return ret;
}

static int tcs3472_write_event_config(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir, bool state)
{
        struct tcs3472_data *data = iio_priv(indio_dev);
        int ret = 0;
        u8 enable_old;

        mutex_lock(&data->lock);

        enable_old = data->enable;

        if (state)
                data->enable |= TCS3472_ENABLE_AIEN;
        else
                data->enable &= ~TCS3472_ENABLE_AIEN;

        if (enable_old != data->enable) {
                ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
                                                data->enable);
                if (ret)
                        data->enable = enable_old;
        }
        mutex_unlock(&data->lock);

        return ret;
}

static irqreturn_t tcs3472_event_handler(int irq, void *priv)
{
        struct iio_dev *indio_dev = priv;
        struct tcs3472_data *data = iio_priv(indio_dev);
        int ret;

        ret = i2c_smbus_read_byte_data(data->client, TCS3472_STATUS);
        if (ret >= 0 && (ret & TCS3472_STATUS_AINT)) {
                iio_push_event(indio_dev, IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
                                                IIO_EV_TYPE_THRESH,
                                                IIO_EV_DIR_EITHER),
                                iio_get_time_ns(indio_dev));

                i2c_smbus_read_byte_data(data->client, TCS3472_INTR_CLEAR);
        }

        return IRQ_HANDLED;
}

static irqreturn_t tcs3472_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct tcs3472_data *data = iio_priv(indio_dev);
        int i, j = 0;
        /* Ensure timestamp is naturally aligned */
        struct {
                u16 chans[4];
                aligned_s64 timestamp;
        } scan = { };

        int ret = tcs3472_req_data(data);
        if (ret < 0)
                goto done;

        iio_for_each_active_channel(indio_dev, i) {
                ret = i2c_smbus_read_word_data(data->client,
                        TCS3472_CDATA + 2*i);
                if (ret < 0)
                        goto done;

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

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

done:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static ssize_t tcs3472_show_int_time_available(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        size_t len = 0;
        int i;

        for (i = 1; i <= 256; i++)
                len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ",
                        2400 * i);

        /* replace trailing space by newline */
        buf[len - 1] = '\n';

        return len;
}

static IIO_CONST_ATTR(calibscale_available, "1 4 16 60");
static IIO_DEV_ATTR_INT_TIME_AVAIL(tcs3472_show_int_time_available);

static struct attribute *tcs3472_attributes[] = {
        &iio_const_attr_calibscale_available.dev_attr.attr,
        &iio_dev_attr_integration_time_available.dev_attr.attr,
        NULL
};

static const struct attribute_group tcs3472_attribute_group = {
        .attrs = tcs3472_attributes,
};

static const struct iio_info tcs3472_info = {
        .read_raw = tcs3472_read_raw,
        .write_raw = tcs3472_write_raw,
        .read_event_value = tcs3472_read_event,
        .write_event_value = tcs3472_write_event,
        .read_event_config = tcs3472_read_event_config,
        .write_event_config = tcs3472_write_event_config,
        .attrs = &tcs3472_attribute_group,
};

static int tcs3472_probe(struct i2c_client *client)
{
        struct tcs3472_data *data;
        struct iio_dev *indio_dev;
        int ret;

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

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

        indio_dev->info = &tcs3472_info;
        indio_dev->name = TCS3472_DRV_NAME;
        indio_dev->channels = tcs3472_channels;
        indio_dev->num_channels = ARRAY_SIZE(tcs3472_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = i2c_smbus_read_byte_data(data->client, TCS3472_ID);
        if (ret < 0)
                return ret;

        if (ret == 0x44)
                dev_info(&client->dev, "TCS34721/34725 found\n");
        else if (ret == 0x4d)
                dev_info(&client->dev, "TCS34723/34727 found\n");
        else
                return -ENODEV;

        ret = i2c_smbus_read_byte_data(data->client, TCS3472_CONTROL);
        if (ret < 0)
                return ret;
        data->control = ret;

        ret = i2c_smbus_read_byte_data(data->client, TCS3472_ATIME);
        if (ret < 0)
                return ret;
        data->atime = ret;

        ret = i2c_smbus_read_word_data(data->client, TCS3472_AILT);
        if (ret < 0)
                return ret;
        data->low_thresh = ret;

        ret = i2c_smbus_read_word_data(data->client, TCS3472_AIHT);
        if (ret < 0)
                return ret;
        data->high_thresh = ret;

        data->apers = 1;
        ret = i2c_smbus_write_byte_data(data->client, TCS3472_PERS,
                                        data->apers);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_byte_data(data->client, TCS3472_ENABLE);
        if (ret < 0)
                return ret;

        /* enable device */
        data->enable = ret | TCS3472_ENABLE_PON | TCS3472_ENABLE_AEN;
        data->enable &= ~TCS3472_ENABLE_AIEN;
        ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
                data->enable);
        if (ret < 0)
                return ret;

        ret = iio_triggered_buffer_setup(indio_dev, NULL,
                tcs3472_trigger_handler, NULL);
        if (ret < 0)
                return ret;

        if (client->irq) {
                ret = request_threaded_irq(client->irq, NULL,
                                           tcs3472_event_handler,
                                           IRQF_TRIGGER_FALLING | IRQF_SHARED |
                                           IRQF_ONESHOT,
                                           client->name, indio_dev);
                if (ret)
                        goto buffer_cleanup;
        }

        ret = iio_device_register(indio_dev);
        if (ret < 0)
                goto free_irq;

        return 0;

free_irq:
        if (client->irq)
                free_irq(client->irq, indio_dev);
buffer_cleanup:
        iio_triggered_buffer_cleanup(indio_dev);
        return ret;
}

static int tcs3472_powerdown(struct tcs3472_data *data)
{
        int ret;
        u8 enable_mask = TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON;

        mutex_lock(&data->lock);

        ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
                data->enable & ~enable_mask);
        if (!ret)
                data->enable &= ~enable_mask;

        mutex_unlock(&data->lock);

        return ret;
}

static void tcs3472_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);

        iio_device_unregister(indio_dev);
        if (client->irq)
                free_irq(client->irq, indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);
        tcs3472_powerdown(iio_priv(indio_dev));
}

static int tcs3472_suspend(struct device *dev)
{
        struct tcs3472_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        return tcs3472_powerdown(data);
}

static int tcs3472_resume(struct device *dev)
{
        struct tcs3472_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        int ret;
        u8 enable_mask = TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON;

        mutex_lock(&data->lock);

        ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
                data->enable | enable_mask);
        if (!ret)
                data->enable |= enable_mask;

        mutex_unlock(&data->lock);

        return ret;
}

static DEFINE_SIMPLE_DEV_PM_OPS(tcs3472_pm_ops, tcs3472_suspend,
                                tcs3472_resume);

static const struct i2c_device_id tcs3472_id[] = {
        { "tcs3472" },
        { }
};
MODULE_DEVICE_TABLE(i2c, tcs3472_id);

static struct i2c_driver tcs3472_driver = {
        .driver = {
                .name   = TCS3472_DRV_NAME,
                .pm     = pm_sleep_ptr(&tcs3472_pm_ops),
        },
        .probe          = tcs3472_probe,
        .remove         = tcs3472_remove,
        .id_table       = tcs3472_id,
};
module_i2c_driver(tcs3472_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("TCS3472 color light sensors driver");
MODULE_LICENSE("GPL");