/*
 * AD7150 capacitive sensor driver supporting AD7150/1/6
 *
 * Copyright 2010-2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
/*
 * AD7150 registers definition
 */

#define AD7150_STATUS              0
#define AD7150_STATUS_OUT1         BIT(3)
#define AD7150_STATUS_OUT2         BIT(5)
#define AD7150_CH1_DATA_HIGH       1
#define AD7150_CH2_DATA_HIGH       3
#define AD7150_CH1_AVG_HIGH        5
#define AD7150_CH2_AVG_HIGH        7
#define AD7150_CH1_SENSITIVITY     9
#define AD7150_CH1_THR_HOLD_H      9
#define AD7150_CH1_TIMEOUT         10
#define AD7150_CH1_SETUP           11
#define AD7150_CH2_SENSITIVITY     12
#define AD7150_CH2_THR_HOLD_H      12
#define AD7150_CH2_TIMEOUT         13
#define AD7150_CH2_SETUP           14
#define AD7150_CFG                 15
#define AD7150_CFG_FIX             BIT(7)
#define AD7150_PD_TIMER            16
#define AD7150_CH1_CAPDAC          17
#define AD7150_CH2_CAPDAC          18
#define AD7150_SN3                 19
#define AD7150_SN2                 20
#define AD7150_SN1                 21
#define AD7150_SN0                 22
#define AD7150_ID                  23

/**
 * struct ad7150_chip_info - instance specific chip data
 * @client: i2c client for this device
 * @current_event: device always has one type of event enabled.
 *	This element stores the event code of the current one.
 * @threshold: thresholds for simple capacitance value events
 * @thresh_sensitivity: threshold for simple capacitance offset
 *	from 'average' value.
 * @mag_sensitity: threshold for magnitude of capacitance offset from
 *	from 'average' value.
 * @thresh_timeout: a timeout, in samples from the moment an
 *	adaptive threshold event occurs to when the average
 *	value jumps to current value.
 * @mag_timeout: a timeout, in sample from the moment an
 *	adaptive magnitude event occurs to when the average
 *	value jumps to the current value.
 * @old_state: store state from previous event, allowing confirmation
 *	of new condition.
 * @conversion_mode: the current conversion mode.
 * @state_lock: ensure consistent state of this structure wrt the
 *	hardware.
 */
struct ad7150_chip_info {
	struct i2c_client *client;
	u64 current_event;
	u16 threshold[2][2];
	u8 thresh_sensitivity[2][2];
	u8 mag_sensitivity[2][2];
	u8 thresh_timeout[2][2];
	u8 mag_timeout[2][2];
	int old_state;
	char *conversion_mode;
	struct mutex state_lock;
};

/*
 * sysfs nodes
 */

static const u8 ad7150_addresses[][6] = {
	{ AD7150_CH1_DATA_HIGH, AD7150_CH1_AVG_HIGH,
	  AD7150_CH1_SETUP, AD7150_CH1_THR_HOLD_H,
	  AD7150_CH1_SENSITIVITY, AD7150_CH1_TIMEOUT },
	{ AD7150_CH2_DATA_HIGH, AD7150_CH2_AVG_HIGH,
	  AD7150_CH2_SETUP, AD7150_CH2_THR_HOLD_H,
	  AD7150_CH2_SENSITIVITY, AD7150_CH2_TIMEOUT },
};

static int ad7150_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val,
			   int *val2,
			   long mask)
{
	int ret;
	struct ad7150_chip_info *chip = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = i2c_smbus_read_word_data(chip->client,
					ad7150_addresses[chan->channel][0]);
		if (ret < 0)
			return ret;
		*val = swab16(ret);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_AVERAGE_RAW:
		ret = i2c_smbus_read_word_data(chip->client,
					ad7150_addresses[chan->channel][1]);
		if (ret < 0)
			return ret;
		*val = swab16(ret);
		return IIO_VAL_INT;
	default:
		return -EINVAL;
	}
}

static int ad7150_read_event_config(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, enum iio_event_type type,
	enum iio_event_direction dir)
{
	int ret;
	u8 threshtype;
	bool adaptive;
	struct ad7150_chip_info *chip = iio_priv(indio_dev);

	ret = i2c_smbus_read_byte_data(chip->client, AD7150_CFG);
	if (ret < 0)
		return ret;

	threshtype = (ret >> 5) & 0x03;
	adaptive = !!(ret & 0x80);

	switch (type) {
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		if (dir == IIO_EV_DIR_RISING)
			return adaptive && (threshtype == 0x1);
		return adaptive && (threshtype == 0x0);
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		if (dir == IIO_EV_DIR_RISING)
			return adaptive && (threshtype == 0x3);
		return adaptive && (threshtype == 0x2);
	case IIO_EV_TYPE_THRESH:
		if (dir == IIO_EV_DIR_RISING)
			return !adaptive && (threshtype == 0x1);
		return !adaptive && (threshtype == 0x0);
	default:
		break;
	}
	return -EINVAL;
}

/* lock should be held */
static int ad7150_write_event_params(struct iio_dev *indio_dev,
				     unsigned int chan,
				     enum iio_event_type type,
				     enum iio_event_direction dir)
{
	int ret;
	u16 value;
	u8 sens, timeout;
	struct ad7150_chip_info *chip = iio_priv(indio_dev);
	int rising = (dir == IIO_EV_DIR_RISING);
	u64 event_code;

	event_code = IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE, chan, type, dir);

	if (event_code != chip->current_event)
		return 0;

	switch (type) {
		/* Note completely different from the adaptive versions */
	case IIO_EV_TYPE_THRESH:
		value = chip->threshold[rising][chan];
		return i2c_smbus_write_word_data(chip->client,
						ad7150_addresses[chan][3],
						swab16(value));
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		sens = chip->mag_sensitivity[rising][chan];
		timeout = chip->mag_timeout[rising][chan];
		break;
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		sens = chip->thresh_sensitivity[rising][chan];
		timeout = chip->thresh_timeout[rising][chan];
		break;
	default:
		return -EINVAL;
	}
	ret = i2c_smbus_write_byte_data(chip->client,
					ad7150_addresses[chan][4],
					sens);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_write_byte_data(chip->client,
					ad7150_addresses[chan][5],
					timeout);
	if (ret < 0)
		return ret;

	return 0;
}

static int ad7150_write_event_config(struct iio_dev *indio_dev,
				     const struct iio_chan_spec *chan,
				     enum iio_event_type type,
				     enum iio_event_direction dir, int state)
{
	u8 thresh_type, cfg, adaptive;
	int ret;
	struct ad7150_chip_info *chip = iio_priv(indio_dev);
	int rising = (dir == IIO_EV_DIR_RISING);
	u64 event_code;

	/* Something must always be turned on */
	if (!state)
		return -EINVAL;

	event_code = IIO_UNMOD_EVENT_CODE(chan->type, chan->channel, type, dir);
	if (event_code == chip->current_event)
		return 0;
	mutex_lock(&chip->state_lock);
	ret = i2c_smbus_read_byte_data(chip->client, AD7150_CFG);
	if (ret < 0)
		goto error_ret;

	cfg = ret & ~((0x03 << 5) | (0x1 << 7));

	switch (type) {
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		adaptive = 1;
		if (rising)
			thresh_type = 0x1;
		else
			thresh_type = 0x0;
		break;
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		adaptive = 1;
		if (rising)
			thresh_type = 0x3;
		else
			thresh_type = 0x2;
		break;
	case IIO_EV_TYPE_THRESH:
		adaptive = 0;
		if (rising)
			thresh_type = 0x1;
		else
			thresh_type = 0x0;
		break;
	default:
		ret = -EINVAL;
		goto error_ret;
	}

	cfg |= (!adaptive << 7) | (thresh_type << 5);

	ret = i2c_smbus_write_byte_data(chip->client, AD7150_CFG, cfg);
	if (ret < 0)
		goto error_ret;

	chip->current_event = event_code;

	/* update control attributes */
	ret = ad7150_write_event_params(indio_dev, chan->channel, type, dir);
error_ret:
	mutex_unlock(&chip->state_lock);

	return ret;
}

static int ad7150_read_event_value(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 ad7150_chip_info *chip = iio_priv(indio_dev);
	int rising = (dir == IIO_EV_DIR_RISING);

	/* Complex register sharing going on here */
	switch (type) {
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		*val = chip->mag_sensitivity[rising][chan->channel];
		return IIO_VAL_INT;
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		*val = chip->thresh_sensitivity[rising][chan->channel];
		return IIO_VAL_INT;
	case IIO_EV_TYPE_THRESH:
		*val = chip->threshold[rising][chan->channel];
		return IIO_VAL_INT;
	default:
		return -EINVAL;
	}
}

static int ad7150_write_event_value(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)
{
	int ret;
	struct ad7150_chip_info *chip = iio_priv(indio_dev);
	int rising = (dir == IIO_EV_DIR_RISING);

	mutex_lock(&chip->state_lock);
	switch (type) {
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		chip->mag_sensitivity[rising][chan->channel] = val;
		break;
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		chip->thresh_sensitivity[rising][chan->channel] = val;
		break;
	case IIO_EV_TYPE_THRESH:
		chip->threshold[rising][chan->channel] = val;
		break;
	default:
		ret = -EINVAL;
		goto error_ret;
	}

	/* write back if active */
	ret = ad7150_write_event_params(indio_dev, chan->channel, type, dir);

error_ret:
	mutex_unlock(&chip->state_lock);
	return ret;
}

static ssize_t ad7150_show_timeout(struct device *dev,
				   struct device_attribute *attr,
				   char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ad7150_chip_info *chip = iio_priv(indio_dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	u8 value;

	/* use the event code for consistency reasons */
	int chan = IIO_EVENT_CODE_EXTRACT_CHAN(this_attr->address);
	int rising = !!(IIO_EVENT_CODE_EXTRACT_DIR(this_attr->address)
			== IIO_EV_DIR_RISING);

	switch (IIO_EVENT_CODE_EXTRACT_TYPE(this_attr->address)) {
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		value = chip->mag_timeout[rising][chan];
		break;
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		value = chip->thresh_timeout[rising][chan];
		break;
	default:
		return -EINVAL;
	}

	return sprintf(buf, "%d\n", value);
}

static ssize_t ad7150_store_timeout(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf,
				    size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ad7150_chip_info *chip = iio_priv(indio_dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int chan = IIO_EVENT_CODE_EXTRACT_CHAN(this_attr->address);
	enum iio_event_direction dir;
	enum iio_event_type type;
	int rising;
	u8 data;
	int ret;

	type = IIO_EVENT_CODE_EXTRACT_TYPE(this_attr->address);
	dir = IIO_EVENT_CODE_EXTRACT_DIR(this_attr->address);
	rising = (dir == IIO_EV_DIR_RISING);

	ret = kstrtou8(buf, 10, &data);
	if (ret < 0)
		return ret;

	mutex_lock(&chip->state_lock);
	switch (type) {
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		chip->mag_timeout[rising][chan] = data;
		break;
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
		chip->thresh_timeout[rising][chan] = data;
		break;
	default:
		ret = -EINVAL;
		goto error_ret;
	}

	ret = ad7150_write_event_params(indio_dev, chan, type, dir);
error_ret:
	mutex_unlock(&chip->state_lock);

	if (ret < 0)
		return ret;

	return len;
}

#define AD7150_TIMEOUT(chan, type, dir, ev_type, ev_dir)		\
	IIO_DEVICE_ATTR(in_capacitance##chan##_##type##_##dir##_timeout, \
		S_IRUGO | S_IWUSR,					\
		&ad7150_show_timeout,					\
		&ad7150_store_timeout,					\
		IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,			\
				     chan,				\
				     IIO_EV_TYPE_##ev_type,		\
				     IIO_EV_DIR_##ev_dir))
static AD7150_TIMEOUT(0, mag_adaptive, rising, MAG_ADAPTIVE, RISING);
static AD7150_TIMEOUT(0, mag_adaptive, falling, MAG_ADAPTIVE, FALLING);
static AD7150_TIMEOUT(1, mag_adaptive, rising, MAG_ADAPTIVE, RISING);
static AD7150_TIMEOUT(1, mag_adaptive, falling, MAG_ADAPTIVE, FALLING);
static AD7150_TIMEOUT(0, thresh_adaptive, rising, THRESH_ADAPTIVE, RISING);
static AD7150_TIMEOUT(0, thresh_adaptive, falling, THRESH_ADAPTIVE, FALLING);
static AD7150_TIMEOUT(1, thresh_adaptive, rising, THRESH_ADAPTIVE, RISING);
static AD7150_TIMEOUT(1, thresh_adaptive, falling, THRESH_ADAPTIVE, FALLING);

static const struct iio_event_spec ad7150_events[] = {
	{
		.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),
	}, {
		.type = IIO_EV_TYPE_THRESH_ADAPTIVE,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	}, {
		.type = IIO_EV_TYPE_THRESH_ADAPTIVE,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	}, {
		.type = IIO_EV_TYPE_MAG_ADAPTIVE,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	}, {
		.type = IIO_EV_TYPE_MAG_ADAPTIVE,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	},
};

static const struct iio_chan_spec ad7150_channels[] = {
	{
		.type = IIO_CAPACITANCE,
		.indexed = 1,
		.channel = 0,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
		BIT(IIO_CHAN_INFO_AVERAGE_RAW),
		.event_spec = ad7150_events,
		.num_event_specs = ARRAY_SIZE(ad7150_events),
	}, {
		.type = IIO_CAPACITANCE,
		.indexed = 1,
		.channel = 1,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
		BIT(IIO_CHAN_INFO_AVERAGE_RAW),
		.event_spec = ad7150_events,
		.num_event_specs = ARRAY_SIZE(ad7150_events),
	},
};

/*
 * threshold events
 */

static irqreturn_t ad7150_event_handler(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct ad7150_chip_info *chip = iio_priv(indio_dev);
	u8 int_status;
	s64 timestamp = iio_get_time_ns(indio_dev);
	int ret;

	ret = i2c_smbus_read_byte_data(chip->client, AD7150_STATUS);
	if (ret < 0)
		return IRQ_HANDLED;

	int_status = ret;

	if ((int_status & AD7150_STATUS_OUT1) &&
	    !(chip->old_state & AD7150_STATUS_OUT1))
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
						    0,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_RISING),
				timestamp);
	else if ((!(int_status & AD7150_STATUS_OUT1)) &&
		 (chip->old_state & AD7150_STATUS_OUT1))
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
						    0,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_FALLING),
			       timestamp);

	if ((int_status & AD7150_STATUS_OUT2) &&
	    !(chip->old_state & AD7150_STATUS_OUT2))
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
						    1,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_RISING),
			       timestamp);
	else if ((!(int_status & AD7150_STATUS_OUT2)) &&
		 (chip->old_state & AD7150_STATUS_OUT2))
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
						    1,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_FALLING),
			       timestamp);
	/* store the status to avoid repushing same events */
	chip->old_state = int_status;

	return IRQ_HANDLED;
}

/* Timeouts not currently handled by core */
static struct attribute *ad7150_event_attributes[] = {
	&iio_dev_attr_in_capacitance0_mag_adaptive_rising_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance0_mag_adaptive_falling_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance1_mag_adaptive_rising_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance1_mag_adaptive_falling_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance0_thresh_adaptive_rising_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance0_thresh_adaptive_falling_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance1_thresh_adaptive_rising_timeout
	.dev_attr.attr,
	&iio_dev_attr_in_capacitance1_thresh_adaptive_falling_timeout
	.dev_attr.attr,
	NULL,
};

static struct attribute_group ad7150_event_attribute_group = {
	.attrs = ad7150_event_attributes,
	.name = "events",
};

static const struct iio_info ad7150_info = {
	.event_attrs = &ad7150_event_attribute_group,
	.driver_module = THIS_MODULE,
	.read_raw = &ad7150_read_raw,
	.read_event_config = &ad7150_read_event_config,
	.write_event_config = &ad7150_write_event_config,
	.read_event_value = &ad7150_read_event_value,
	.write_event_value = &ad7150_write_event_value,
};

/*
 * device probe and remove
 */

static int ad7150_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	int ret;
	struct ad7150_chip_info *chip;
	struct iio_dev *indio_dev;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
	if (!indio_dev)
		return -ENOMEM;
	chip = iio_priv(indio_dev);
	mutex_init(&chip->state_lock);
	/* this is only used for device removal purposes */
	i2c_set_clientdata(client, indio_dev);

	chip->client = client;

	indio_dev->name = id->name;
	indio_dev->channels = ad7150_channels;
	indio_dev->num_channels = ARRAY_SIZE(ad7150_channels);
	/* Establish that the iio_dev is a child of the i2c device */
	indio_dev->dev.parent = &client->dev;

	indio_dev->info = &ad7150_info;

	indio_dev->modes = INDIO_DIRECT_MODE;

	if (client->irq) {
		ret = devm_request_threaded_irq(&client->dev, client->irq,
					   NULL,
					   &ad7150_event_handler,
					   IRQF_TRIGGER_RISING |
					   IRQF_TRIGGER_FALLING |
					   IRQF_ONESHOT,
					   "ad7150_irq1",
					   indio_dev);
		if (ret)
			return ret;
	}

	if (client->dev.platform_data) {
		ret = devm_request_threaded_irq(&client->dev, *(unsigned int *)
					   client->dev.platform_data,
					   NULL,
					   &ad7150_event_handler,
					   IRQF_TRIGGER_RISING |
					   IRQF_TRIGGER_FALLING |
					   IRQF_ONESHOT,
					   "ad7150_irq2",
					   indio_dev);
		if (ret)
			return ret;
	}

	ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
	if (ret)
		return ret;

	dev_info(&client->dev, "%s capacitive sensor registered,irq: %d\n",
		 id->name, client->irq);

	return 0;
}

static const struct i2c_device_id ad7150_id[] = {
	{ "ad7150", 0 },
	{ "ad7151", 0 },
	{ "ad7156", 0 },
	{}
};

MODULE_DEVICE_TABLE(i2c, ad7150_id);

static struct i2c_driver ad7150_driver = {
	.driver = {
		.name = "ad7150",
	},
	.probe = ad7150_probe,
	.id_table = ad7150_id,
};
module_i2c_driver(ad7150_driver);

MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
MODULE_DESCRIPTION("Analog Devices AD7150/1/6 capacitive sensor driver");
MODULE_LICENSE("GPL v2");