// SPDX-License-Identifier: GPL-2.0-only
/*
 * tcs3414.c - Support for TAOS TCS3414 digital color sensor
 *
 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * Digital color sensor with 16-bit channels for red, green, blue, clear);
 * 7-bit I2C slave address 0x39 (TCS3414) or 0x29, 0x49, 0x59 (TCS3413,
 * TCS3415, TCS3416, resp.)
 *
 * TODO: sync, interrupt support, thresholds, prescaler
 */

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

#define TCS3414_DRV_NAME "tcs3414"

#define TCS3414_COMMAND BIT(7)
#define TCS3414_COMMAND_WORD (TCS3414_COMMAND | BIT(5))

#define TCS3414_CONTROL (TCS3414_COMMAND | 0x00)
#define TCS3414_TIMING (TCS3414_COMMAND | 0x01)
#define TCS3414_ID (TCS3414_COMMAND | 0x04)
#define TCS3414_GAIN (TCS3414_COMMAND | 0x07)
#define TCS3414_DATA_GREEN (TCS3414_COMMAND_WORD | 0x10)
#define TCS3414_DATA_RED (TCS3414_COMMAND_WORD | 0x12)
#define TCS3414_DATA_BLUE (TCS3414_COMMAND_WORD | 0x14)
#define TCS3414_DATA_CLEAR (TCS3414_COMMAND_WORD | 0x16)

#define TCS3414_CONTROL_ADC_VALID BIT(4)
#define TCS3414_CONTROL_ADC_EN BIT(1)
#define TCS3414_CONTROL_POWER BIT(0)

#define TCS3414_INTEG_MASK GENMASK(1, 0)
#define TCS3414_INTEG_12MS 0x0
#define TCS3414_INTEG_100MS 0x1
#define TCS3414_INTEG_400MS 0x2

#define TCS3414_GAIN_MASK GENMASK(5, 4)
#define TCS3414_GAIN_SHIFT 4

struct tcs3414_data {
        struct i2c_client *client;
        u8 control;
        u8 gain;
        u8 timing;
};

#define TCS3414_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_SCALE) | \
                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, \
        }, \
}

/* scale factors: 1/gain */
static const int tcs3414_scales[][2] = {
        {1, 0}, {0, 250000}, {0, 62500}, {0, 15625}
};

/* integration time in ms */
static const int tcs3414_times[] = { 12, 100, 400 };

static const struct iio_chan_spec tcs3414_channels[] = {
        TCS3414_CHANNEL(GREEN, 0, TCS3414_DATA_GREEN),
        TCS3414_CHANNEL(RED, 1, TCS3414_DATA_RED),
        TCS3414_CHANNEL(BLUE, 2, TCS3414_DATA_BLUE),
        TCS3414_CHANNEL(CLEAR, 3, TCS3414_DATA_CLEAR),
        IIO_CHAN_SOFT_TIMESTAMP(4),
};

static int tcs3414_req_data(struct tcs3414_data *data)
{
        int tries = 25;
        int ret;

        ret = i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control | TCS3414_CONTROL_ADC_EN);
        if (ret < 0)
                return ret;

        while (tries--) {
                ret = i2c_smbus_read_byte_data(data->client, TCS3414_CONTROL);
                if (ret < 0)
                        return ret;
                if (ret & TCS3414_CONTROL_ADC_VALID)
                        break;
                msleep(20);
        }

        ret = i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control);
        if (ret < 0)
                return ret;

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

        return 0;
}

static int tcs3414_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val, int *val2, long mask)
{
        struct tcs3414_data *data = iio_priv(indio_dev);
        int i, ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                ret = tcs3414_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_SCALE:
                i = (data->gain & TCS3414_GAIN_MASK) >> TCS3414_GAIN_SHIFT;
                *val = tcs3414_scales[i][0];
                *val2 = tcs3414_scales[i][1];
                return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_INT_TIME:
                *val = 0;
                *val2 = tcs3414_times[data->timing & TCS3414_INTEG_MASK] * 1000;
                return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
}

static int tcs3414_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        struct tcs3414_data *data = iio_priv(indio_dev);
        int i;

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                for (i = 0; i < ARRAY_SIZE(tcs3414_scales); i++) {
                        if (val == tcs3414_scales[i][0] &&
                                val2 == tcs3414_scales[i][1]) {
                                data->gain &= ~TCS3414_GAIN_MASK;
                                data->gain |= i << TCS3414_GAIN_SHIFT;
                                return i2c_smbus_write_byte_data(
                                        data->client, TCS3414_GAIN,
                                        data->gain);
                        }
                }
                return -EINVAL;
        case IIO_CHAN_INFO_INT_TIME:
                if (val != 0)
                        return -EINVAL;
                for (i = 0; i < ARRAY_SIZE(tcs3414_times); i++) {
                        if (val2 == tcs3414_times[i] * 1000) {
                                data->timing &= ~TCS3414_INTEG_MASK;
                                data->timing |= i;
                                return i2c_smbus_write_byte_data(
                                        data->client, TCS3414_TIMING,
                                        data->timing);
                        }
                }
                return -EINVAL;
        default:
                return -EINVAL;
        }
}

static irqreturn_t tcs3414_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct tcs3414_data *data = iio_priv(indio_dev);
        int i, j = 0;
        /* Ensure timestamp is naturally aligned */
        struct {
                u16 chans[4];
                aligned_s64 timestamp;
        } scan = { };


        iio_for_each_active_channel(indio_dev, i) {
                int ret = i2c_smbus_read_word_data(data->client,
                        TCS3414_DATA_GREEN + 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 IIO_CONST_ATTR(scale_available, "1 0.25 0.0625 0.015625");
static IIO_CONST_ATTR_INT_TIME_AVAIL("0.012 0.1 0.4");

static struct attribute *tcs3414_attributes[] = {
        &iio_const_attr_scale_available.dev_attr.attr,
        &iio_const_attr_integration_time_available.dev_attr.attr,
        NULL
};

static const struct attribute_group tcs3414_attribute_group = {
        .attrs = tcs3414_attributes,
};

static const struct iio_info tcs3414_info = {
        .read_raw = tcs3414_read_raw,
        .write_raw = tcs3414_write_raw,
        .attrs = &tcs3414_attribute_group,
};

static int tcs3414_buffer_postenable(struct iio_dev *indio_dev)
{
        struct tcs3414_data *data = iio_priv(indio_dev);

        data->control |= TCS3414_CONTROL_ADC_EN;
        return i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control);
}

static int tcs3414_buffer_predisable(struct iio_dev *indio_dev)
{
        struct tcs3414_data *data = iio_priv(indio_dev);

        data->control &= ~TCS3414_CONTROL_ADC_EN;
        return i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control);
}

static const struct iio_buffer_setup_ops tcs3414_buffer_setup_ops = {
        .postenable = tcs3414_buffer_postenable,
        .predisable = tcs3414_buffer_predisable,
};

static int tcs3414_powerdown(struct tcs3414_data *data)
{
        return i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control & ~(TCS3414_CONTROL_POWER |
                TCS3414_CONTROL_ADC_EN));
}

static void tcs3414_powerdown_cleanup(void *data)
{
        tcs3414_powerdown(data);
}

static int tcs3414_probe(struct i2c_client *client)
{
        struct tcs3414_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;

        indio_dev->info = &tcs3414_info;
        indio_dev->name = TCS3414_DRV_NAME;
        indio_dev->channels = tcs3414_channels;
        indio_dev->num_channels = ARRAY_SIZE(tcs3414_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = i2c_smbus_read_byte_data(data->client, TCS3414_ID);
        if (ret < 0)
                return ret;

        switch (ret & 0xf0) {
        case 0x00:
                dev_info(&client->dev, "TCS3404 found\n");
                break;
        case 0x10:
                dev_info(&client->dev, "TCS3413/14/15/16 found\n");
                break;
        default:
                return -ENODEV;
        }

        data->control = TCS3414_CONTROL_POWER;
        ret = i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control);
        if (ret < 0)
                return ret;

        ret = devm_add_action_or_reset(&client->dev, tcs3414_powerdown_cleanup,
                                       data);
        if (ret < 0)
                return ret;

        data->timing = TCS3414_INTEG_12MS; /* free running */
        ret = i2c_smbus_write_byte_data(data->client, TCS3414_TIMING,
                data->timing);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_byte_data(data->client, TCS3414_GAIN);
        if (ret < 0)
                return ret;
        data->gain = ret;

        ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
                tcs3414_trigger_handler, &tcs3414_buffer_setup_ops);
        if (ret < 0)
                return ret;

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

static int tcs3414_suspend(struct device *dev)
{
        struct tcs3414_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        return tcs3414_powerdown(data);
}

static int tcs3414_resume(struct device *dev)
{
        struct tcs3414_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        return i2c_smbus_write_byte_data(data->client, TCS3414_CONTROL,
                data->control);
}

static DEFINE_SIMPLE_DEV_PM_OPS(tcs3414_pm_ops, tcs3414_suspend,
                                tcs3414_resume);

static const struct i2c_device_id tcs3414_id[] = {
        { "tcs3414" },
        { }
};
MODULE_DEVICE_TABLE(i2c, tcs3414_id);

static struct i2c_driver tcs3414_driver = {
        .driver = {
                .name   = TCS3414_DRV_NAME,
                .pm     = pm_sleep_ptr(&tcs3414_pm_ops),
        },
        .probe          = tcs3414_probe,
        .id_table       = tcs3414_id,
};
module_i2c_driver(tcs3414_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("TCS3414 digital color sensors driver");
MODULE_LICENSE("GPL");