/**
 * opt3001.c - Texas Instruments OPT3001 Light Sensor
 *
 * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
 *
 * Author: Felipe Balbi <balbi@ti.com>
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 of the License
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/types.h>

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

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

#include "opt3001.h"

#define OPT3001_RESULT		0x00
#define OPT3001_CONFIGURATION	0x01
#define OPT3001_LOW_LIMIT	0x02
#define OPT3001_HIGH_LIMIT	0x03
#define OPT3001_MANUFACTURER_ID	0x7e
#define OPT3001_DEVICE_ID	0x7f

#define OPT3001_CONFIGURATION_RN_MASK (0xf << 12)
#define OPT3001_CONFIGURATION_RN_AUTO (0xc << 12)

#define OPT3001_CONFIGURATION_CT	BIT(11)

#define OPT3001_CONFIGURATION_M_MASK	(3 << 9)
#define OPT3001_CONFIGURATION_M_SHUTDOWN (0 << 9)
#define OPT3001_CONFIGURATION_M_SINGLE (1 << 9)
#define OPT3001_CONFIGURATION_M_CONTINUOUS (2 << 9) /* also 3 << 9 */

#define OPT3001_CONFIGURATION_OVF	BIT(8)
#define OPT3001_CONFIGURATION_CRF	BIT(7)
#define OPT3001_CONFIGURATION_FH	BIT(6)
#define OPT3001_CONFIGURATION_FL	BIT(5)
#define OPT3001_CONFIGURATION_L		BIT(4)
#define OPT3001_CONFIGURATION_POL	BIT(3)
#define OPT3001_CONFIGURATION_ME	BIT(2)

#define OPT3001_CONFIGURATION_FC_MASK	(3 << 0)

#define OPT3001_REG_EXPONENT(n)	((n) >> 12)
#define OPT3001_REG_MANTISSA(n)	((n) & 0xfff)

#define OPT3001_CONVERSION_XTRA_TIME_DIV_1 3
#define OPT3001_CONVERSION_XTRA_TIME_DIV_2 2


struct ring_buf_data {
	s32	illuminance_unscaled;
	s64	timestamp;
};

struct opt3001 {
	struct i2c_client	*client;
	struct device		*dev;

	struct iio_trigger	*limit_trig;

	struct mutex		lock;

	u32			int_time;
	u32			mode;

	u16			high_thresh_mantissa;
	u16			low_thresh_mantissa;

	u8			high_thresh_exp;
	u8			low_thresh_exp;

	bool			trigger_on;

	struct ring_buf_data	data;

	unsigned int		hysteresis:1;
};

struct opt3001_scale {
	int	val;
	int	val2;
};

static const struct opt3001_scale opt3001_scales[] = {
	{
		.val = 40,
		.val2 = 950000,
	},
	{
		.val = 81,
		.val2 = 900000,
	},
	{
		.val = 163,
		.val2 = 800000,
	},
	{
		.val = 327,
		.val2 = 600000,
	},
	{
		.val = 655,
		.val2 = 200000,
	},
	{
		.val = 1310,
		.val2 = 400000,
	},
	{
		.val = 2620,
		.val2 = 800000,
	},
	{
		.val = 5241,
		.val2 = 600000,
	},
	{
		.val = 10483,
		.val2 = 200000,
	},
	{
		.val = 20966,
		.val2 = 400000,
	},
	{
		.val = 41932,
		.val2 = 800000,
	},
	{
		.val = 83865,
		.val2 = 600000,
	},
};

static int opt3001_find_scale(const struct opt3001 *opt, int val,
		int val2, u8 *exponent)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(opt3001_scales); i++) {
		const struct opt3001_scale *scale = &opt3001_scales[i];

		if ((val*1000 + val2/1000) <= (scale->val*1000 + scale->val2/1000)) {
			*exponent = i;
			return 0;
		}
	}

	return -EINVAL;
}

static void opt3001_to_iio_ret(struct opt3001 *opt, u8 exponent,
		u16 mantissa, int *val, int *val2)
{
	int lux;

	lux = 10 * (mantissa << exponent);
	*val = lux / 1000;
	*val2 = (lux - (*val * 1000)) * 1000;
}

static void opt3001_set_mode(struct opt3001 *opt, u16 *reg, u16 mode)
{
	*reg &= ~OPT3001_CONFIGURATION_M_MASK;
	*reg |= mode;
	opt->mode = mode;
}

static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.8");

static struct attribute *opt3001_attributes[] = {
	&iio_const_attr_integration_time_available.dev_attr.attr,
	NULL
};

static const struct attribute_group opt3001_attribute_group = {
	.attrs = opt3001_attributes,
};

static const struct iio_event_spec opt3001_event_spec[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_HYSTERESIS) |
			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_HYSTERESIS) |
			BIT(IIO_EV_INFO_ENABLE),
	},
};

static const struct iio_chan_spec opt3001_channels[] = {
	{
		.type = IIO_LIGHT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
		                      BIT(IIO_CHAN_INFO_INT_TIME) |
		                      BIT(IIO_CHAN_INFO_SCALE),
		.event_spec = opt3001_event_spec,
		.num_event_specs = ARRAY_SIZE(opt3001_event_spec),
		.scan_type = {
			.sign = 's',
			.realbits = 32,
			.storagebits = 32
		}
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2)
{
	int ret;
	u16 mantissa;
	u16 reg;
	u8 exponent;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;
	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);

	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
			reg);
	if (ret < 0) {
		dev_err(opt->dev, "failed to write register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	/* Wait for conversion to complete and give it some extra time. It can take
	 * up to 960ms when integration time is configured to 800ms and 120ms when
	 * integration time is configured to 100ms
	 */
	usleep_range(opt->int_time + (opt->int_time / OPT3001_CONVERSION_XTRA_TIME_DIV_1),
			 opt->int_time + (opt->int_time / OPT3001_CONVERSION_XTRA_TIME_DIV_2));

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;
	if (!(reg & OPT3001_CONFIGURATION_CRF))
		return -EPIPE;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_RESULT);
		return ret;
	}

	exponent = OPT3001_REG_EXPONENT(ret);
	mantissa = OPT3001_REG_MANTISSA(ret);

	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);

	return IIO_VAL_INT_PLUS_MICRO;
}

static int opt3001_get_lux_continuous_mode(struct opt3001 *opt, int *val, int *val2)
{
	int ret;

	u16 mantissa;
	u16 reg;
	u8 exponent;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;

	if (!(reg & OPT3001_CONFIGURATION_CRF)) {
		/* Wait for conversion to complete and give it some extra time. It can take
		 * up to 880ms when integration time is configured to 800ms and 110ms when
		 * integration time is configured to 100ms
		 */
		usleep_range(opt->int_time + (opt->int_time / OPT3001_CONVERSION_XTRA_TIME_DIV_1),
			 opt->int_time + (opt->int_time / OPT3001_CONVERSION_XTRA_TIME_DIV_2));

		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
		if (ret < 0) {
			dev_err(opt->dev, "failed to read register %02x\n",
					OPT3001_CONFIGURATION);
			return ret;
		}

		reg = ret;
		if (!(reg & OPT3001_CONFIGURATION_CRF))
			return -EPIPE;
	}

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_RESULT);
		return ret;
	}

	exponent = OPT3001_REG_EXPONENT(ret);
	mantissa = OPT3001_REG_MANTISSA(ret);

	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);

	return IIO_VAL_INT_PLUS_MICRO;
}

static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
{
	*val = 0;
	*val2 = opt->int_time;

	return IIO_VAL_INT_PLUS_MICRO;
}

static int opt3001_set_int_time(struct opt3001 *opt, int time)
{
	int ret;
	u16 reg;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;

	switch (time) {
	case 100000:
		reg &= ~OPT3001_CONFIGURATION_CT;
		opt->int_time = 100000;
		break;
	case 800000:
		reg |= OPT3001_CONFIGURATION_CT;
		opt->int_time = 800000;
		break;
	default:
		return -EINVAL;
	}

	return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
			reg);
}

static int opt3001_read_raw(struct iio_dev *iio,
		struct iio_chan_spec const *chan, int *val, int *val2,
		long mask)
{
	struct opt3001 *opt = iio_priv(iio);
	int ret = 0;

	if (chan->type != IIO_LIGHT)
		return -EINVAL;

	mutex_lock(&opt->lock);

	switch (mask) {
	case IIO_CHAN_INFO_PROCESSED:
		if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
			ret = opt3001_get_lux_continuous_mode(opt, val, val2);
		else
			ret = opt3001_get_lux(opt, val, val2);
		break;
	case IIO_CHAN_INFO_INT_TIME:
		ret = opt3001_get_int_time(opt, val, val2);
		break;
	case IIO_CHAN_INFO_SCALE:
		/*
		 * Illuminance values have a maximum precision of 0.01.
		 * Values are written into the ring buffer unscaled to avoid
		 * fractional values; userspace needs to scale them by 0.01.
		 */
		*val = 0;
		*val2 = 10000;
		ret = IIO_VAL_INT_PLUS_MICRO;
		break;
	default:
		ret = -EINVAL;
	}

	mutex_unlock(&opt->lock);

	return ret;
}

static int opt3001_write_raw(struct iio_dev *iio,
		struct iio_chan_spec const *chan, int val, int val2,
		long mask)
{
	struct opt3001 *opt = iio_priv(iio);
	int ret = 0;

	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
		return -EBUSY;

	if (chan->type != IIO_LIGHT)
		return -EINVAL;

	if (mask != IIO_CHAN_INFO_INT_TIME)
		return -EINVAL;

	mutex_lock(&opt->lock);
	ret = opt3001_set_int_time(opt, val2);
	mutex_unlock(&opt->lock);

	return ret;
}

static int opt3001_read_event_value(struct iio_dev *iio,
		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 opt3001 *opt = iio_priv(iio);
	int ret = IIO_VAL_INT_PLUS_MICRO;

	mutex_lock(&opt->lock);

	switch (dir) {
	case IIO_EV_DIR_RISING:
		opt3001_to_iio_ret(opt, opt->high_thresh_exp,
			opt->high_thresh_mantissa, val, val2);
		break;
	case IIO_EV_DIR_FALLING:
		opt3001_to_iio_ret(opt, opt->low_thresh_exp,
			opt->low_thresh_mantissa, val, val2);
		break;
	default:
		ret = -EINVAL;
	}

	mutex_unlock(&opt->lock);

	return ret;
}

static int opt3001_write_event_value(struct iio_dev *iio,
		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 opt3001 *opt = iio_priv(iio);
	int ret = 0;

	u16 mantissa;
	u16 value;
	u16 reg;

	u8 exponent;

	mutex_lock(&opt->lock);

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		goto err;
	}

	if (info == IIO_EV_INFO_HYSTERESIS)
		opt->hysteresis = true;
	else
		opt->hysteresis = false;

	ret = opt3001_find_scale(opt, val, val2, &exponent);
	if (ret < 0) {
		dev_err(opt->dev, "can't find scale for %d.%d\n", val, val2);
		goto err;
	}

	mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
	value = exponent << 12 | mantissa;

	switch (dir) {
	case IIO_EV_DIR_RISING:
		reg = OPT3001_HIGH_LIMIT;
		opt->high_thresh_mantissa = mantissa;
		opt->high_thresh_exp = exponent;
		break;
	case IIO_EV_DIR_FALLING:
		reg = OPT3001_LOW_LIMIT;
		opt->low_thresh_mantissa = mantissa;
		opt->low_thresh_exp = exponent;
		break;
	default:
		ret = -EINVAL;
		goto err;
	}

	ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
	if (ret < 0) {
		dev_err(opt->dev, "failed to write register %02x\n", reg);
		goto err;
	}

err:
	mutex_unlock(&opt->lock);

	return ret;
}

static int opt3001_read_event_config(struct iio_dev *iio,
		const struct iio_chan_spec *chan, enum iio_event_type type,
		enum iio_event_direction dir)
{
	struct opt3001 *opt = iio_priv(iio);

	return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
}

static int opt3001_write_event_config(struct iio_dev *iio,
		const struct iio_chan_spec *chan, enum iio_event_type type,
		enum iio_event_direction dir, int state)
{
	struct opt3001 *opt = iio_priv(iio);
	int ret;
	u16 mode;
	u16 reg;

	if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
		return 0;

	if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
		return 0;

	mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
		: OPT3001_CONFIGURATION_M_SHUTDOWN;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;
	opt3001_set_mode(opt, &reg, mode);

	if (opt->hysteresis)
		reg &= ~OPT3001_CONFIGURATION_L;
	else
		reg |= OPT3001_CONFIGURATION_L;

	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
			reg);
	if (ret < 0) {
		dev_err(opt->dev, "failed to write register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	/* wait for mode change to go through */
	usleep_range(opt->int_time + 5000, opt->int_time + 10000);

	return 0;
}

static const struct iio_info opt3001_info = {
	.driver_module = THIS_MODULE,
	.attrs = &opt3001_attribute_group,
	.read_raw = opt3001_read_raw,
	.write_raw = opt3001_write_raw,
	.read_event_value_new = opt3001_read_event_value,
	.write_event_value_new = opt3001_write_event_value,
	.read_event_config_new = opt3001_read_event_config,
	.write_event_config_new = opt3001_write_event_config,
};

static int opt3001_read_id(struct opt3001 *opt)
{
	char manufacturer[2];
	u16 device_id;
	int ret;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_MANUFACTURER_ID);
		return ret;
	}

	manufacturer[0] = ret >> 8;
	manufacturer[1] = ret & 0xff;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_DEVICE_ID);
		return ret;
	}

	device_id = ret;

	dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
			manufacturer[1], device_id);

	return 0;
}

static int opt3001_configure(struct opt3001 *opt)
{
	int ret;
	u16 reg;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;

	/* Set the default integration time to 100 ms */
	opt->int_time = 100000;
	reg &= ~OPT3001_CONFIGURATION_CT;

	opt->hysteresis = true;
	reg &= ~OPT3001_CONFIGURATION_L;
	reg &= ~OPT3001_CONFIGURATION_RN_MASK;
	reg |= OPT3001_CONFIGURATION_RN_AUTO;

	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
			reg);
	if (ret < 0) {
		dev_err(opt->dev, "failed to write register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_LOW_LIMIT);
		return ret;
	}

	opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
	opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_HIGH_LIMIT);
		return ret;
	}

	opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
	opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);

	return 0;
}

static irqreturn_t opt3001_trig_poll(int irq, void *_iio)
{
	struct iio_dev *iio = _iio;
	struct opt3001 *opt = iio_priv(iio);

	if (opt->trigger_on)
		iio_trigger_poll(opt->limit_trig, 0);

	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
		return IRQ_WAKE_THREAD;
	else
		return IRQ_HANDLED;
}

static irqreturn_t opt3001_irq(int irq, void *_iio)
{
	struct iio_dev *iio = _iio;
	struct opt3001 *opt = iio_priv(iio);
	int ret;

	mutex_lock(&opt->lock);

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		goto out;
	}

	if (!(ret & OPT3001_CONFIGURATION_CT))
		goto out;

	if (ret & OPT3001_CONFIGURATION_FH)
		iio_push_event(iio, IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
					IIO_EV_TYPE_THRESH,
					IIO_EV_DIR_RISING), iio_get_time_ns());

	if (ret & OPT3001_CONFIGURATION_FL)
		iio_push_event(iio, IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
					IIO_EV_TYPE_THRESH,
					IIO_EV_DIR_FALLING), iio_get_time_ns());

out:
	mutex_unlock(&opt->lock);
	return IRQ_HANDLED;
}

irqreturn_t opt3001_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *iio = pf->indio_dev;
	struct opt3001 *opt = iio_priv(iio);
	int ret;
	u32 reg;

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_RESULT);
		goto out;
	}

	reg = ret;

	opt->data.illuminance_unscaled = OPT3001_REG_MANTISSA(reg) <<
		OPT3001_REG_EXPONENT(reg);

	if (iio->scan_timestamp)
		opt->data.timestamp = pf->timestamp;

	iio_push_to_buffers(iio, (unsigned char *)&opt->data);

out:
	iio_trigger_notify_done(iio->trig);

	return IRQ_HANDLED;
}

static int opt3001_trigger_set_state(struct iio_trigger *trig, bool state)
{
	struct iio_dev *iio = iio_trigger_get_drvdata(trig);
	struct opt3001 *opt = iio_priv(iio);

	opt->trigger_on = state;

	return 0;
}

static const struct iio_trigger_ops opt3001_trigger_ops = {
	.set_trigger_state = opt3001_trigger_set_state,
	.try_reenable = NULL,
	.owner = THIS_MODULE,
};

static int opt3001_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;

	struct iio_dev *iio;
	struct opt3001 *opt;
	int irq = client->irq;
	int ret = -ENOMEM;

	iio = iio_device_alloc(sizeof(*opt));
	if (!iio)
		goto err_iio_alloc;

	opt = iio_priv(iio);
	opt->client = client;
	opt->dev = dev;

	mutex_init(&opt->lock);
	i2c_set_clientdata(client, iio);

	ret = opt3001_read_id(opt);
	if (ret)
		goto err_read;

	ret = opt3001_configure(opt);
	if (ret)
		goto err_read;

	iio->name = client->name;
	iio->channels = opt3001_channels;
	iio->num_channels = ARRAY_SIZE(opt3001_channels);
	iio->dev.parent = dev;
	iio->modes = INDIO_DIRECT_MODE;
	iio->info = &opt3001_info;

	opt->limit_trig = iio_trigger_alloc("%s-trigger", iio->name);
	if (!opt->limit_trig) {
		ret = -ENOMEM;
		goto err_read;
	}

	opt->limit_trig->dev.parent = &client->dev;
	opt->limit_trig->ops = &opt3001_trigger_ops;
	iio_trigger_set_drvdata(opt->limit_trig, iio);
	ret = iio_trigger_register(opt->limit_trig);
	if (ret)
		goto err_trigger_register;

	ret = opt3001_allocate_ring(iio);
	if (ret < 0) {
		dev_err(&client->dev,
			"Failed: iio triggered buffer setup\n");
		goto err_buffer_setup;
	}

	ret = iio_device_register(iio);
	if (ret) {
		dev_err(dev, "failed to register IIO device\n");
		goto err_device_register;
	}

	if (irq > 0) {
		ret = request_threaded_irq(irq, opt3001_trig_poll, opt3001_irq,
				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING
				| IRQF_ONESHOT, "opt3001", iio);
		if (ret) {
			dev_err(dev, "failed to request IRQ #%d\n", irq);
			goto err_request_irq;
		}
	}

	return 0;

err_request_irq:
	iio_device_unregister(iio);

err_device_register:
	opt3001_deallocate_ring(iio);

err_buffer_setup:
	iio_trigger_unregister(opt->limit_trig);

err_trigger_register:
	iio_trigger_free(opt->limit_trig);

err_read:
	iio_device_free(iio);

err_iio_alloc:
	return ret;
}

static int opt3001_remove(struct i2c_client *client)
{
	struct iio_dev *iio = i2c_get_clientdata(client);
	struct opt3001 *opt = iio_priv(iio);
	int ret;
	u16 reg;

	free_irq(client->irq, iio);
	iio_device_unregister(iio);
	opt3001_deallocate_ring(iio);
	iio_trigger_unregister(opt->limit_trig);

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
	if (ret < 0) {
		dev_err(opt->dev, "failed to read register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	reg = ret;
	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);

	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
			reg);
	if (ret < 0) {
		dev_err(opt->dev, "failed to write register %02x\n",
				OPT3001_CONFIGURATION);
		return ret;
	}

	iio_device_free(iio);

	return 0;
}

static const struct of_device_id opt3001_of_match[] = {
	{ .compatible = "ti,opt3001" },
	{ }
};
MODULE_DEVICE_TABLE(of, opt3001_of_match);

static const struct i2c_device_id opt3001_id[] = {
	{ "opt3001", 0 },
	{ } /* Terminating Entry */
};
MODULE_DEVICE_TABLE(i2c, opt3001_id);

static struct i2c_driver opt3001_driver = {
	.probe = opt3001_probe,
	.remove = opt3001_remove,
	.id_table = opt3001_id,

	.driver = {
		.name = "opt3001",
		.of_match_table = of_match_ptr(opt3001_of_match),
		.owner = THIS_MODULE,
	},
};

module_i2c_driver(opt3001_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
MODULE_DESCRIPTION("Texas Instruments OPT3001 Light Sensor Driver");