/*
 * apds9300.c - IIO driver for Avago APDS9300 ambient light sensor
 *
 * Copyright 2013 Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>

#define APDS9300_DRV_NAME "apds9300"
#define APDS9300_IRQ_NAME "apds9300_event"

/* Command register bits */
#define APDS9300_CMD	BIT(7) /* Select command register. Must write as 1 */
#define APDS9300_WORD	BIT(5) /* I2C write/read: if 1 word, if 0 byte */
#define APDS9300_CLEAR	BIT(6) /* Interrupt clear. Clears pending interrupt */

/* Register set */
#define APDS9300_CONTROL	0x00 /* Control of basic functions */
#define APDS9300_THRESHLOWLOW	0x02 /* Low byte of low interrupt threshold */
#define APDS9300_THRESHHIGHLOW	0x04 /* Low byte of high interrupt threshold */
#define APDS9300_INTERRUPT	0x06 /* Interrupt control */
#define APDS9300_DATA0LOW	0x0c /* Low byte of ADC channel 0 */
#define APDS9300_DATA1LOW	0x0e /* Low byte of ADC channel 1 */

/* Power on/off value for APDS9300_CONTROL register */
#define APDS9300_POWER_ON	0x03
#define APDS9300_POWER_OFF	0x00

/* Interrupts */
#define APDS9300_INTR_ENABLE	0x10
/* Interrupt Persist Function: Any value outside of threshold range */
#define APDS9300_THRESH_INTR	0x01

#define APDS9300_THRESH_MAX	0xffff /* Max threshold value */

struct apds9300_data {
	struct i2c_client *client;
	struct mutex mutex;
	int power_state;
	int thresh_low;
	int thresh_hi;
	int intr_en;
};

/* Lux calculation */

/* Calculated values 1000 * (CH1/CH0)^1.4 for CH1/CH0 from 0 to 0.52 */
static const u16 apds9300_lux_ratio[] = {
	0, 2, 4, 7, 11, 15, 19, 24, 29, 34, 40, 45, 51, 57, 64, 70, 77, 84, 91,
	98, 105, 112, 120, 128, 136, 144, 152, 160, 168, 177, 185, 194, 203,
	212, 221, 230, 239, 249, 258, 268, 277, 287, 297, 307, 317, 327, 337,
	347, 358, 368, 379, 390, 400,
};

static unsigned long apds9300_calculate_lux(u16 ch0, u16 ch1)
{
	unsigned long lux, tmp;

	/* avoid division by zero */
	if (ch0 == 0)
		return 0;

	tmp = DIV_ROUND_UP(ch1 * 100, ch0);
	if (tmp <= 52) {
		lux = 3150 * ch0 - (unsigned long)DIV_ROUND_UP_ULL(ch0
				* apds9300_lux_ratio[tmp] * 5930ull, 1000);
	} else if (tmp <= 65) {
		lux = 2290 * ch0 - 2910 * ch1;
	} else if (tmp <= 80) {
		lux = 1570 * ch0 - 1800 * ch1;
	} else if (tmp <= 130) {
		lux = 338 * ch0 - 260 * ch1;
	} else {
		lux = 0;
	}

	return lux / 100000;
}

static int apds9300_get_adc_val(struct apds9300_data *data, int adc_number)
{
	int ret;
	u8 flags = APDS9300_CMD | APDS9300_WORD;

	if (!data->power_state)
		return -EBUSY;

	/* Select ADC0 or ADC1 data register */
	flags |= adc_number ? APDS9300_DATA1LOW : APDS9300_DATA0LOW;

	ret = i2c_smbus_read_word_data(data->client, flags);
	if (ret < 0)
		dev_err(&data->client->dev,
			"failed to read ADC%d value\n", adc_number);

	return ret;
}

static int apds9300_set_thresh_low(struct apds9300_data *data, int value)
{
	int ret;

	if (!data->power_state)
		return -EBUSY;

	if (value > APDS9300_THRESH_MAX)
		return -EINVAL;

	ret = i2c_smbus_write_word_data(data->client, APDS9300_THRESHLOWLOW
			| APDS9300_CMD | APDS9300_WORD, value);
	if (ret) {
		dev_err(&data->client->dev, "failed to set thresh_low\n");
		return ret;
	}
	data->thresh_low = value;

	return 0;
}

static int apds9300_set_thresh_hi(struct apds9300_data *data, int value)
{
	int ret;

	if (!data->power_state)
		return -EBUSY;

	if (value > APDS9300_THRESH_MAX)
		return -EINVAL;

	ret = i2c_smbus_write_word_data(data->client, APDS9300_THRESHHIGHLOW
			| APDS9300_CMD | APDS9300_WORD, value);
	if (ret) {
		dev_err(&data->client->dev, "failed to set thresh_hi\n");
		return ret;
	}
	data->thresh_hi = value;

	return 0;
}

static int apds9300_set_intr_state(struct apds9300_data *data, int state)
{
	int ret;
	u8 cmd;

	if (!data->power_state)
		return -EBUSY;

	cmd = state ? APDS9300_INTR_ENABLE | APDS9300_THRESH_INTR : 0x00;
	ret = i2c_smbus_write_byte_data(data->client,
			APDS9300_INTERRUPT | APDS9300_CMD, cmd);
	if (ret) {
		dev_err(&data->client->dev,
			"failed to set interrupt state %d\n", state);
		return ret;
	}
	data->intr_en = state;

	return 0;
}

static int apds9300_set_power_state(struct apds9300_data *data, int state)
{
	int ret;
	u8 cmd;

	cmd = state ? APDS9300_POWER_ON : APDS9300_POWER_OFF;
	ret = i2c_smbus_write_byte_data(data->client,
			APDS9300_CONTROL | APDS9300_CMD, cmd);
	if (ret) {
		dev_err(&data->client->dev,
			"failed to set power state %d\n", state);
		return ret;
	}
	data->power_state = state;

	return 0;
}

static void apds9300_clear_intr(struct apds9300_data *data)
{
	int ret;

	ret = i2c_smbus_write_byte(data->client, APDS9300_CLEAR | APDS9300_CMD);
	if (ret < 0)
		dev_err(&data->client->dev, "failed to clear interrupt\n");
}

static int apds9300_chip_init(struct apds9300_data *data)
{
	int ret;

	/* Need to set power off to ensure that the chip is off */
	ret = apds9300_set_power_state(data, 0);
	if (ret < 0)
		goto err;
	/*
	 * Probe the chip. To do so we try to power up the device and then to
	 * read back the 0x03 code
	 */
	ret = apds9300_set_power_state(data, 1);
	if (ret < 0)
		goto err;
	ret = i2c_smbus_read_byte_data(data->client,
			APDS9300_CONTROL | APDS9300_CMD);
	if (ret != APDS9300_POWER_ON) {
		ret = -ENODEV;
		goto err;
	}
	/*
	 * Disable interrupt to ensure thai it is doesn't enable
	 * i.e. after device soft reset
	 */
	ret = apds9300_set_intr_state(data, 0);
	if (ret < 0)
		goto err;

	return 0;

err:
	dev_err(&data->client->dev, "failed to init the chip\n");
	return ret;
}

static int apds9300_read_raw(struct iio_dev *indio_dev,
		struct iio_chan_spec const *chan, int *val, int *val2,
		long mask)
{
	int ch0, ch1, ret = -EINVAL;
	struct apds9300_data *data = iio_priv(indio_dev);

	mutex_lock(&data->mutex);
	switch (chan->type) {
	case IIO_LIGHT:
		ch0 = apds9300_get_adc_val(data, 0);
		if (ch0 < 0) {
			ret = ch0;
			break;
		}
		ch1 = apds9300_get_adc_val(data, 1);
		if (ch1 < 0) {
			ret = ch1;
			break;
		}
		*val = apds9300_calculate_lux(ch0, ch1);
		ret = IIO_VAL_INT;
		break;
	case IIO_INTENSITY:
		ret = apds9300_get_adc_val(data, chan->channel);
		if (ret < 0)
			break;
		*val = ret;
		ret = IIO_VAL_INT;
		break;
	default:
		break;
	}
	mutex_unlock(&data->mutex);

	return ret;
}

static int apds9300_read_thresh(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 apds9300_data *data = iio_priv(indio_dev);

	switch (dir) {
	case IIO_EV_DIR_RISING:
		*val = data->thresh_hi;
		break;
	case IIO_EV_DIR_FALLING:
		*val = data->thresh_low;
		break;
	default:
		return -EINVAL;
	}

	return IIO_VAL_INT;
}

static int apds9300_write_thresh(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 apds9300_data *data = iio_priv(indio_dev);
	int ret;

	mutex_lock(&data->mutex);
	if (dir == IIO_EV_DIR_RISING)
		ret = apds9300_set_thresh_hi(data, val);
	else
		ret = apds9300_set_thresh_low(data, val);
	mutex_unlock(&data->mutex);

	return ret;
}

static int apds9300_read_interrupt_config(struct iio_dev *indio_dev,
		const struct iio_chan_spec *chan,
		enum iio_event_type type,
		enum iio_event_direction dir)
{
	struct apds9300_data *data = iio_priv(indio_dev);

	return data->intr_en;
}

static int apds9300_write_interrupt_config(struct iio_dev *indio_dev,
		const struct iio_chan_spec *chan, enum iio_event_type type,
		enum iio_event_direction dir, int state)
{
	struct apds9300_data *data = iio_priv(indio_dev);
	int ret;

	mutex_lock(&data->mutex);
	ret = apds9300_set_intr_state(data, state);
	mutex_unlock(&data->mutex);

	return ret;
}

static const struct iio_info apds9300_info_no_irq = {
	.driver_module	= THIS_MODULE,
	.read_raw	= apds9300_read_raw,
};

static const struct iio_info apds9300_info = {
	.driver_module		= THIS_MODULE,
	.read_raw		= apds9300_read_raw,
	.read_event_value	= apds9300_read_thresh,
	.write_event_value	= apds9300_write_thresh,
	.read_event_config	= apds9300_read_interrupt_config,
	.write_event_config	= apds9300_write_interrupt_config,
};

static const struct iio_event_spec apds9300_event_spec[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	},
};

static const struct iio_chan_spec apds9300_channels[] = {
	{
		.type = IIO_LIGHT,
		.channel = 0,
		.indexed = true,
		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
	}, {
		.type = IIO_INTENSITY,
		.channel = 0,
		.channel2 = IIO_MOD_LIGHT_BOTH,
		.indexed = true,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.event_spec = apds9300_event_spec,
		.num_event_specs = ARRAY_SIZE(apds9300_event_spec),
	}, {
		.type = IIO_INTENSITY,
		.channel = 1,
		.channel2 = IIO_MOD_LIGHT_IR,
		.indexed = true,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	},
};

static irqreturn_t apds9300_interrupt_handler(int irq, void *private)
{
	struct iio_dev *dev_info = private;
	struct apds9300_data *data = iio_priv(dev_info);

	iio_push_event(dev_info,
		       IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
					    IIO_EV_TYPE_THRESH,
					    IIO_EV_DIR_EITHER),
		       iio_get_time_ns(dev_info));

	apds9300_clear_intr(data);

	return IRQ_HANDLED;
}

static int apds9300_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
{
	struct apds9300_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;

	ret = apds9300_chip_init(data);
	if (ret < 0)
		goto err;

	mutex_init(&data->mutex);

	indio_dev->dev.parent = &client->dev;
	indio_dev->channels = apds9300_channels;
	indio_dev->num_channels = ARRAY_SIZE(apds9300_channels);
	indio_dev->name = APDS9300_DRV_NAME;
	indio_dev->modes = INDIO_DIRECT_MODE;

	if (client->irq)
		indio_dev->info = &apds9300_info;
	else
		indio_dev->info = &apds9300_info_no_irq;

	if (client->irq) {
		ret = devm_request_threaded_irq(&client->dev, client->irq,
				NULL, apds9300_interrupt_handler,
				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
				APDS9300_IRQ_NAME, indio_dev);
		if (ret) {
			dev_err(&client->dev, "irq request error %d\n", -ret);
			goto err;
		}
	}

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

	return 0;

err:
	/* Ensure that power off in case of error */
	apds9300_set_power_state(data, 0);
	return ret;
}

static int apds9300_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct apds9300_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	/* Ensure that power off and interrupts are disabled */
	apds9300_set_intr_state(data, 0);
	apds9300_set_power_state(data, 0);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int apds9300_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct apds9300_data *data = iio_priv(indio_dev);
	int ret;

	mutex_lock(&data->mutex);
	ret = apds9300_set_power_state(data, 0);
	mutex_unlock(&data->mutex);

	return ret;
}

static int apds9300_resume(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct apds9300_data *data = iio_priv(indio_dev);
	int ret;

	mutex_lock(&data->mutex);
	ret = apds9300_set_power_state(data, 1);
	mutex_unlock(&data->mutex);

	return ret;
}

static SIMPLE_DEV_PM_OPS(apds9300_pm_ops, apds9300_suspend, apds9300_resume);
#define APDS9300_PM_OPS (&apds9300_pm_ops)
#else
#define APDS9300_PM_OPS NULL
#endif

static const struct i2c_device_id apds9300_id[] = {
	{ APDS9300_DRV_NAME, 0 },
	{ }
};

MODULE_DEVICE_TABLE(i2c, apds9300_id);

static struct i2c_driver apds9300_driver = {
	.driver = {
		.name	= APDS9300_DRV_NAME,
		.pm	= APDS9300_PM_OPS,
	},
	.probe		= apds9300_probe,
	.remove		= apds9300_remove,
	.id_table	= apds9300_id,
};

module_i2c_driver(apds9300_driver);

MODULE_AUTHOR("Kravchenko Oleksandr <o.v.kravchenko@globallogic.com>");
MODULE_AUTHOR("GlobalLogic inc.");
MODULE_DESCRIPTION("APDS9300 ambient light photo sensor driver");
MODULE_LICENSE("GPL");