/*
 * IIO driver for the light sensor ISL29028.
 * ISL29028 is Concurrent Ambient Light and Proximity Sensor
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 * Copyright (c) 2016-2017 Brian Masney <masneyb@onstation.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Datasheets:
 *  - http://www.intersil.com/content/dam/Intersil/documents/isl2/isl29028.pdf
 *  - http://www.intersil.com/content/dam/Intersil/documents/isl2/isl29030.pdf
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/pm_runtime.h>

#define ISL29028_CONV_TIME_MS			100

#define ISL29028_REG_CONFIGURE			0x01

#define ISL29028_CONF_ALS_IR_MODE_ALS		0
#define ISL29028_CONF_ALS_IR_MODE_IR		BIT(0)
#define ISL29028_CONF_ALS_IR_MODE_MASK		BIT(0)

#define ISL29028_CONF_ALS_RANGE_LOW_LUX		0
#define ISL29028_CONF_ALS_RANGE_HIGH_LUX	BIT(1)
#define ISL29028_CONF_ALS_RANGE_MASK		BIT(1)

#define ISL29028_CONF_ALS_DIS			0
#define ISL29028_CONF_ALS_EN			BIT(2)
#define ISL29028_CONF_ALS_EN_MASK		BIT(2)

#define ISL29028_CONF_PROX_SLP_SH		4
#define ISL29028_CONF_PROX_SLP_MASK		(7 << ISL29028_CONF_PROX_SLP_SH)

#define ISL29028_CONF_PROX_EN			BIT(7)
#define ISL29028_CONF_PROX_EN_MASK		BIT(7)

#define ISL29028_REG_INTERRUPT			0x02

#define ISL29028_REG_PROX_DATA			0x08
#define ISL29028_REG_ALSIR_L			0x09
#define ISL29028_REG_ALSIR_U			0x0A

#define ISL29028_REG_TEST1_MODE			0x0E
#define ISL29028_REG_TEST2_MODE			0x0F

#define ISL29028_NUM_REGS			(ISL29028_REG_TEST2_MODE + 1)

#define ISL29028_POWER_OFF_DELAY_MS		2000

struct isl29028_prox_data {
	int sampling_int;
	int sampling_fract;
	int sleep_time;
};

static const struct isl29028_prox_data isl29028_prox_data[] = {
	{   1, 250000, 800 },
	{   2, 500000, 400 },
	{   5,      0, 200 },
	{  10,      0, 100 },
	{  13, 300000,  75 },
	{  20,      0,  50 },
	{  80,      0,  13 }, /*
			       * Note: Data sheet lists 12.5 ms sleep time.
			       * Round up a half millisecond for msleep().
			       */
	{ 100,  0,   0 }
};

enum isl29028_als_ir_mode {
	ISL29028_MODE_NONE = 0,
	ISL29028_MODE_ALS,
	ISL29028_MODE_IR,
};

struct isl29028_chip {
	struct mutex			lock;
	struct regmap			*regmap;
	int				prox_sampling_int;
	int				prox_sampling_frac;
	bool				enable_prox;
	int				lux_scale;
	enum isl29028_als_ir_mode	als_ir_mode;
};

static int isl29028_find_prox_sleep_index(int sampling_int, int sampling_fract)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(isl29028_prox_data); ++i) {
		if (isl29028_prox_data[i].sampling_int == sampling_int &&
		    isl29028_prox_data[i].sampling_fract == sampling_fract)
			return i;
	}

	return -EINVAL;
}

static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
					int sampling_int, int sampling_fract)
{
	struct device *dev = regmap_get_device(chip->regmap);
	int sleep_index, ret;

	sleep_index = isl29028_find_prox_sleep_index(sampling_int,
						     sampling_fract);
	if (sleep_index < 0)
		return sleep_index;

	ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
				 ISL29028_CONF_PROX_SLP_MASK,
				 sleep_index << ISL29028_CONF_PROX_SLP_SH);

	if (ret < 0) {
		dev_err(dev, "%s(): Error %d setting the proximity sampling\n",
			__func__, ret);
		return ret;
	}

	chip->prox_sampling_int = sampling_int;
	chip->prox_sampling_frac = sampling_fract;

	return ret;
}

static int isl29028_enable_proximity(struct isl29028_chip *chip)
{
	int prox_index, ret;

	ret = isl29028_set_proxim_sampling(chip, chip->prox_sampling_int,
					   chip->prox_sampling_frac);
	if (ret < 0)
		return ret;

	ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
				 ISL29028_CONF_PROX_EN_MASK,
				 ISL29028_CONF_PROX_EN);
	if (ret < 0)
		return ret;

	/* Wait for conversion to be complete for first sample */
	prox_index = isl29028_find_prox_sleep_index(chip->prox_sampling_int,
						    chip->prox_sampling_frac);
	if (prox_index < 0)
		return prox_index;

	msleep(isl29028_prox_data[prox_index].sleep_time);

	return 0;
}

static int isl29028_set_als_scale(struct isl29028_chip *chip, int lux_scale)
{
	struct device *dev = regmap_get_device(chip->regmap);
	int val = (lux_scale == 2000) ? ISL29028_CONF_ALS_RANGE_HIGH_LUX :
					ISL29028_CONF_ALS_RANGE_LOW_LUX;
	int ret;

	ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
				 ISL29028_CONF_ALS_RANGE_MASK, val);
	if (ret < 0) {
		dev_err(dev, "%s(): Error %d setting the ALS scale\n", __func__,
			ret);
		return ret;
	}

	chip->lux_scale = lux_scale;

	return ret;
}

static int isl29028_set_als_ir_mode(struct isl29028_chip *chip,
				    enum isl29028_als_ir_mode mode)
{
	int ret;

	if (chip->als_ir_mode == mode)
		return 0;

	ret = isl29028_set_als_scale(chip, chip->lux_scale);
	if (ret < 0)
		return ret;

	switch (mode) {
	case ISL29028_MODE_ALS:
		ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
					 ISL29028_CONF_ALS_IR_MODE_MASK,
					 ISL29028_CONF_ALS_IR_MODE_ALS);
		if (ret < 0)
			return ret;

		ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
					 ISL29028_CONF_ALS_RANGE_MASK,
					 ISL29028_CONF_ALS_RANGE_HIGH_LUX);
		break;
	case ISL29028_MODE_IR:
		ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
					 ISL29028_CONF_ALS_IR_MODE_MASK,
					 ISL29028_CONF_ALS_IR_MODE_IR);
		break;
	case ISL29028_MODE_NONE:
		return regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
					  ISL29028_CONF_ALS_EN_MASK,
					  ISL29028_CONF_ALS_DIS);
	}

	if (ret < 0)
		return ret;

	/* Enable the ALS/IR */
	ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
				 ISL29028_CONF_ALS_EN_MASK,
				 ISL29028_CONF_ALS_EN);
	if (ret < 0)
		return ret;

	/* Need to wait for conversion time if ALS/IR mode enabled */
	msleep(ISL29028_CONV_TIME_MS);

	chip->als_ir_mode = mode;

	return 0;
}

static int isl29028_read_als_ir(struct isl29028_chip *chip, int *als_ir)
{
	struct device *dev = regmap_get_device(chip->regmap);
	unsigned int lsb;
	unsigned int msb;
	int ret;

	ret = regmap_read(chip->regmap, ISL29028_REG_ALSIR_L, &lsb);
	if (ret < 0) {
		dev_err(dev,
			"%s(): Error %d reading register ALSIR_L\n",
			__func__, ret);
		return ret;
	}

	ret = regmap_read(chip->regmap, ISL29028_REG_ALSIR_U, &msb);
	if (ret < 0) {
		dev_err(dev,
			"%s(): Error %d reading register ALSIR_U\n",
			__func__, ret);
		return ret;
	}

	*als_ir = ((msb & 0xF) << 8) | (lsb & 0xFF);

	return 0;
}

static int isl29028_read_proxim(struct isl29028_chip *chip, int *prox)
{
	struct device *dev = regmap_get_device(chip->regmap);
	unsigned int data;
	int ret;

	if (!chip->enable_prox) {
		ret = isl29028_enable_proximity(chip);
		if (ret < 0)
			return ret;

		chip->enable_prox = true;
	}

	ret = regmap_read(chip->regmap, ISL29028_REG_PROX_DATA, &data);
	if (ret < 0) {
		dev_err(dev, "%s(): Error %d reading register PROX_DATA\n",
			__func__, ret);
		return ret;
	}

	*prox = data;

	return 0;
}

static int isl29028_als_get(struct isl29028_chip *chip, int *als_data)
{
	struct device *dev = regmap_get_device(chip->regmap);
	int ret;
	int als_ir_data;

	ret = isl29028_set_als_ir_mode(chip, ISL29028_MODE_ALS);
	if (ret < 0) {
		dev_err(dev, "%s(): Error %d enabling ALS mode\n", __func__,
			ret);
		return ret;
	}

	ret = isl29028_read_als_ir(chip, &als_ir_data);
	if (ret < 0)
		return ret;

	/*
	 * convert als data count to lux.
	 * if lux_scale = 125,  lux = count * 0.031
	 * if lux_scale = 2000, lux = count * 0.49
	 */
	if (chip->lux_scale == 125)
		als_ir_data = (als_ir_data * 31) / 1000;
	else
		als_ir_data = (als_ir_data * 49) / 100;

	*als_data = als_ir_data;

	return 0;
}

static int isl29028_ir_get(struct isl29028_chip *chip, int *ir_data)
{
	struct device *dev = regmap_get_device(chip->regmap);
	int ret;

	ret = isl29028_set_als_ir_mode(chip, ISL29028_MODE_IR);
	if (ret < 0) {
		dev_err(dev, "%s(): Error %d enabling IR mode\n", __func__,
			ret);
		return ret;
	}

	return isl29028_read_als_ir(chip, ir_data);
}

static int isl29028_set_pm_runtime_busy(struct isl29028_chip *chip, bool on)
{
	struct device *dev = regmap_get_device(chip->regmap);
	int ret;

	if (on) {
		ret = pm_runtime_get_sync(dev);
		if (ret < 0)
			pm_runtime_put_noidle(dev);
	} else {
		pm_runtime_mark_last_busy(dev);
		ret = pm_runtime_put_autosuspend(dev);
	}

	return ret;
}

/* Channel IO */
static int isl29028_write_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int val, int val2, long mask)
{
	struct isl29028_chip *chip = iio_priv(indio_dev);
	struct device *dev = regmap_get_device(chip->regmap);
	int ret;

	ret = isl29028_set_pm_runtime_busy(chip, true);
	if (ret < 0)
		return ret;

	mutex_lock(&chip->lock);

	ret = -EINVAL;
	switch (chan->type) {
	case IIO_PROXIMITY:
		if (mask != IIO_CHAN_INFO_SAMP_FREQ) {
			dev_err(dev,
				"%s(): proximity: Mask value 0x%08lx is not supported\n",
				__func__, mask);
			break;
		}

		if (val < 1 || val > 100) {
			dev_err(dev,
				"%s(): proximity: Sampling frequency %d is not in the range [1:100]\n",
				__func__, val);
			break;
		}

		ret = isl29028_set_proxim_sampling(chip, val, val2);
		break;
	case IIO_LIGHT:
		if (mask != IIO_CHAN_INFO_SCALE) {
			dev_err(dev,
				"%s(): light: Mask value 0x%08lx is not supported\n",
				__func__, mask);
			break;
		}

		if (val != 125 && val != 2000) {
			dev_err(dev,
				"%s(): light: Lux scale %d is not in the set {125, 2000}\n",
				__func__, val);
			break;
		}

		ret = isl29028_set_als_scale(chip, val);
		break;
	default:
		dev_err(dev, "%s(): Unsupported channel type %x\n",
			__func__, chan->type);
		break;
	}

	mutex_unlock(&chip->lock);

	if (ret < 0)
		return ret;

	ret = isl29028_set_pm_runtime_busy(chip, false);
	if (ret < 0)
		return ret;

	return ret;
}

static int isl29028_read_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int *val, int *val2, long mask)
{
	struct isl29028_chip *chip = iio_priv(indio_dev);
	struct device *dev = regmap_get_device(chip->regmap);
	int ret, pm_ret;

	ret = isl29028_set_pm_runtime_busy(chip, true);
	if (ret < 0)
		return ret;

	mutex_lock(&chip->lock);

	ret = -EINVAL;
	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	case IIO_CHAN_INFO_PROCESSED:
		switch (chan->type) {
		case IIO_LIGHT:
			ret = isl29028_als_get(chip, val);
			break;
		case IIO_INTENSITY:
			ret = isl29028_ir_get(chip, val);
			break;
		case IIO_PROXIMITY:
			ret = isl29028_read_proxim(chip, val);
			break;
		default:
			break;
		}

		if (ret < 0)
			break;

		ret = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_SAMP_FREQ:
		if (chan->type != IIO_PROXIMITY)
			break;

		*val = chip->prox_sampling_int;
		*val2 = chip->prox_sampling_frac;
		ret = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_SCALE:
		if (chan->type != IIO_LIGHT)
			break;
		*val = chip->lux_scale;
		ret = IIO_VAL_INT;
		break;
	default:
		dev_err(dev, "%s(): mask value 0x%08lx is not supported\n",
			__func__, mask);
		break;
	}

	mutex_unlock(&chip->lock);

	if (ret < 0)
		return ret;

	/**
	 * Preserve the ret variable if the call to
	 * isl29028_set_pm_runtime_busy() is successful so the reading
	 * (if applicable) is returned to user space.
	 */
	pm_ret = isl29028_set_pm_runtime_busy(chip, false);
	if (pm_ret < 0)
		return pm_ret;

	return ret;
}

static IIO_CONST_ATTR(in_proximity_sampling_frequency_available,
				"1.25 2.5 5 10 13.3 20 80 100");
static IIO_CONST_ATTR(in_illuminance_scale_available, "125 2000");

#define ISL29028_CONST_ATTR(name) (&iio_const_attr_##name.dev_attr.attr)
static struct attribute *isl29028_attributes[] = {
	ISL29028_CONST_ATTR(in_proximity_sampling_frequency_available),
	ISL29028_CONST_ATTR(in_illuminance_scale_available),
	NULL,
};

static const struct attribute_group isl29108_group = {
	.attrs = isl29028_attributes,
};

static const struct iio_chan_spec isl29028_channels[] = {
	{
		.type = IIO_LIGHT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
		BIT(IIO_CHAN_INFO_SCALE),
	}, {
		.type = IIO_INTENSITY,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}, {
		.type = IIO_PROXIMITY,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
		BIT(IIO_CHAN_INFO_SAMP_FREQ),
	}
};

static const struct iio_info isl29028_info = {
	.attrs = &isl29108_group,
	.driver_module = THIS_MODULE,
	.read_raw = isl29028_read_raw,
	.write_raw = isl29028_write_raw,
};

static int isl29028_clear_configure_reg(struct isl29028_chip *chip)
{
	struct device *dev = regmap_get_device(chip->regmap);
	int ret;

	ret = regmap_write(chip->regmap, ISL29028_REG_CONFIGURE, 0x0);
	if (ret < 0)
		dev_err(dev, "%s(): Error %d clearing the CONFIGURE register\n",
			__func__, ret);

	chip->als_ir_mode = ISL29028_MODE_NONE;
	chip->enable_prox = false;

	return ret;
}

static bool isl29028_is_volatile_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case ISL29028_REG_INTERRUPT:
	case ISL29028_REG_PROX_DATA:
	case ISL29028_REG_ALSIR_L:
	case ISL29028_REG_ALSIR_U:
		return true;
	default:
		return false;
	}
}

static const struct regmap_config isl29028_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.volatile_reg = isl29028_is_volatile_reg,
	.max_register = ISL29028_NUM_REGS - 1,
	.num_reg_defaults_raw = ISL29028_NUM_REGS,
	.cache_type = REGCACHE_RBTREE,
};

static int isl29028_probe(struct i2c_client *client,
			  const struct i2c_device_id *id)
{
	struct isl29028_chip *chip;
	struct iio_dev *indio_dev;
	int ret;

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

	chip = iio_priv(indio_dev);

	i2c_set_clientdata(client, indio_dev);
	mutex_init(&chip->lock);

	chip->regmap = devm_regmap_init_i2c(client, &isl29028_regmap_config);
	if (IS_ERR(chip->regmap)) {
		ret = PTR_ERR(chip->regmap);
		dev_err(&client->dev, "%s: Error %d initializing regmap\n",
			__func__, ret);
		return ret;
	}

	chip->enable_prox  = false;
	chip->prox_sampling_int = 20;
	chip->prox_sampling_frac = 0;
	chip->lux_scale = 2000;

	ret = regmap_write(chip->regmap, ISL29028_REG_TEST1_MODE, 0x0);
	if (ret < 0) {
		dev_err(&client->dev,
			"%s(): Error %d writing to TEST1_MODE register\n",
			__func__, ret);
		return ret;
	}

	ret = regmap_write(chip->regmap, ISL29028_REG_TEST2_MODE, 0x0);
	if (ret < 0) {
		dev_err(&client->dev,
			"%s(): Error %d writing to TEST2_MODE register\n",
			__func__, ret);
		return ret;
	}

	ret = isl29028_clear_configure_reg(chip);
	if (ret < 0)
		return ret;

	indio_dev->info = &isl29028_info;
	indio_dev->channels = isl29028_channels;
	indio_dev->num_channels = ARRAY_SIZE(isl29028_channels);
	indio_dev->name = id->name;
	indio_dev->dev.parent = &client->dev;
	indio_dev->modes = INDIO_DIRECT_MODE;

	pm_runtime_enable(&client->dev);
	pm_runtime_set_autosuspend_delay(&client->dev,
					 ISL29028_POWER_OFF_DELAY_MS);
	pm_runtime_use_autosuspend(&client->dev);

	ret = iio_device_register(indio_dev);
	if (ret < 0) {
		dev_err(&client->dev,
			"%s(): iio registration failed with error %d\n",
			__func__, ret);
		return ret;
	}

	return 0;
}

static int isl29028_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct isl29028_chip *chip = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);
	pm_runtime_put_noidle(&client->dev);

	return isl29028_clear_configure_reg(chip);
}

static int __maybe_unused isl29028_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct isl29028_chip *chip = iio_priv(indio_dev);
	int ret;

	mutex_lock(&chip->lock);

	ret = isl29028_clear_configure_reg(chip);

	mutex_unlock(&chip->lock);

	return ret;
}

static int __maybe_unused isl29028_resume(struct device *dev)
{
	/**
	 * The specific component (ALS/IR or proximity) will enable itself as
	 * needed the next time that the user requests a reading. This is done
	 * above in isl29028_set_als_ir_mode() and isl29028_enable_proximity().
	 */
	return 0;
}

static const struct dev_pm_ops isl29028_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
				pm_runtime_force_resume)
	SET_RUNTIME_PM_OPS(isl29028_suspend, isl29028_resume, NULL)
};

static const struct i2c_device_id isl29028_id[] = {
	{"isl29028", 0},
	{"isl29030", 0},
	{}
};
MODULE_DEVICE_TABLE(i2c, isl29028_id);

static const struct of_device_id isl29028_of_match[] = {
	{ .compatible = "isl,isl29028", }, /* for backward compat., don't use */
	{ .compatible = "isil,isl29028", },
	{ .compatible = "isil,isl29030", },
	{ },
};
MODULE_DEVICE_TABLE(of, isl29028_of_match);

static struct i2c_driver isl29028_driver = {
	.driver  = {
		.name = "isl29028",
		.pm = &isl29028_pm_ops,
		.of_match_table = isl29028_of_match,
	},
	.probe	 = isl29028_probe,
	.remove  = isl29028_remove,
	.id_table = isl29028_id,
};

module_i2c_driver(isl29028_driver);

MODULE_DESCRIPTION("ISL29028 Ambient Light and Proximity Sensor driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");