iio/light/opt4060.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2024 Axis Communications AB
 *
 * Datasheet: https://www.ti.com/lit/gpn/opt4060
 *
 * Device driver for the Texas Instruments OPT4060 RGBW Color Sensor.
 */

#include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/math64.h>
#include <linux/units.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/events.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

/* OPT4060 register set */
#define OPT4060_RED_MSB				0x00
#define OPT4060_RED_LSB				0x01
#define OPT4060_GREEN_MSB			0x02
#define OPT4060_GREEN_LSB			0x03
#define OPT4060_BLUE_MSB			0x04
#define OPT4060_BLUE_LSB			0x05
#define OPT4060_CLEAR_MSB			0x06
#define OPT4060_CLEAR_LSB			0x07
#define OPT4060_THRESHOLD_LOW			0x08
#define OPT4060_THRESHOLD_HIGH			0x09
#define OPT4060_CTRL				0x0a
#define OPT4060_INT_CTRL			0x0b
#define OPT4060_RES_CTRL			0x0c
#define OPT4060_DEVICE_ID			0x11

/* OPT4060 register mask */
#define OPT4060_EXPONENT_MASK			GENMASK(15, 12)
#define OPT4060_MSB_MASK			GENMASK(11, 0)
#define OPT4060_LSB_MASK			GENMASK(15, 8)
#define OPT4060_COUNTER_MASK			GENMASK(7, 4)
#define OPT4060_CRC_MASK			GENMASK(3, 0)

/* OPT4060 device id mask */
#define OPT4060_DEVICE_ID_MASK			GENMASK(11, 0)

/* OPT4060 control register masks */
#define OPT4060_CTRL_QWAKE_MASK			BIT(15)
#define OPT4060_CTRL_RANGE_MASK			GENMASK(13, 10)
#define OPT4060_CTRL_CONV_TIME_MASK		GENMASK(9, 6)
#define OPT4060_CTRL_OPER_MODE_MASK		GENMASK(5, 4)
#define OPT4060_CTRL_LATCH_MASK			BIT(3)
#define OPT4060_CTRL_INT_POL_MASK		BIT(2)
#define OPT4060_CTRL_FAULT_COUNT_MASK		GENMASK(1, 0)

/* OPT4060 interrupt control register masks */
#define OPT4060_INT_CTRL_THRESH_SEL		GENMASK(6, 5)
#define OPT4060_INT_CTRL_OUTPUT			BIT(4)
#define OPT4060_INT_CTRL_INT_CFG		GENMASK(3, 2)
#define OPT4060_INT_CTRL_THRESHOLD		0x0
#define OPT4060_INT_CTRL_NEXT_CH		0x1
#define OPT4060_INT_CTRL_ALL_CH			0x3

/* OPT4060 result control register masks */
#define OPT4060_RES_CTRL_OVERLOAD		BIT(3)
#define OPT4060_RES_CTRL_CONV_READY		BIT(2)
#define OPT4060_RES_CTRL_FLAG_H			BIT(1)
#define OPT4060_RES_CTRL_FLAG_L			BIT(0)

/* OPT4060 constants */
#define OPT4060_DEVICE_ID_VAL			0x821

/* OPT4060 operating modes */
#define OPT4060_CTRL_OPER_MODE_OFF		0x0
#define OPT4060_CTRL_OPER_MODE_FORCED		0x1
#define OPT4060_CTRL_OPER_MODE_ONE_SHOT		0x2
#define OPT4060_CTRL_OPER_MODE_CONTINUOUS	0x3

/* OPT4060 conversion control register definitions */
#define OPT4060_CTRL_CONVERSION_0_6MS		0x0
#define OPT4060_CTRL_CONVERSION_1MS		0x1
#define OPT4060_CTRL_CONVERSION_1_8MS		0x2
#define OPT4060_CTRL_CONVERSION_3_4MS		0x3
#define OPT4060_CTRL_CONVERSION_6_5MS		0x4
#define OPT4060_CTRL_CONVERSION_12_7MS		0x5
#define OPT4060_CTRL_CONVERSION_25MS		0x6
#define OPT4060_CTRL_CONVERSION_50MS		0x7
#define OPT4060_CTRL_CONVERSION_100MS		0x8
#define OPT4060_CTRL_CONVERSION_200MS		0x9
#define OPT4060_CTRL_CONVERSION_400MS		0xa
#define OPT4060_CTRL_CONVERSION_800MS		0xb

/* OPT4060 fault count control register definitions */
#define OPT4060_CTRL_FAULT_COUNT_1		0x0
#define OPT4060_CTRL_FAULT_COUNT_2		0x1
#define OPT4060_CTRL_FAULT_COUNT_4		0x2
#define OPT4060_CTRL_FAULT_COUNT_8		0x3

/* OPT4060 scale light level range definitions */
#define OPT4060_CTRL_LIGHT_SCALE_AUTO		12

/* OPT4060 default values */
#define OPT4060_DEFAULT_CONVERSION_TIME OPT4060_CTRL_CONVERSION_50MS

/*
 * enum opt4060_chan_type - OPT4060 channel types
 * @OPT4060_RED:	Red channel.
 * @OPT4060_GREEN:	Green channel.
 * @OPT4060_BLUE:	Blue channel.
 * @OPT4060_CLEAR:	Clear (white) channel.
 * @OPT4060_ILLUM:	Calculated illuminance channel.
 * @OPT4060_NUM_CHANS:	Number of channel types.
 */
enum opt4060_chan_type {
	OPT4060_RED,
	OPT4060_GREEN,
	OPT4060_BLUE,
	OPT4060_CLEAR,
	OPT4060_ILLUM,
	OPT4060_NUM_CHANS
};

struct opt4060_chip {
	struct regmap *regmap;
	struct device *dev;
	struct iio_trigger *trig;
	u8 int_time;
	int irq;
	/*
	 * Mutex for protecting sensor irq settings. Switching between interrupt
	 * on each sample and on thresholds needs to be synchronized.
	 */
	struct mutex irq_setting_lock;
	/*
	 * Mutex for protecting event enabling.
	 */
	struct mutex event_enabling_lock;
	struct completion completion;
	bool thresh_event_lo_active;
	bool thresh_event_hi_active;
};

struct opt4060_channel_factor {
	u32 mul;
	u32 div;
};

static const int opt4060_int_time_available[][2] = {
	{ 0,    600 },
	{ 0,   1000 },
	{ 0,   1800 },
	{ 0,   3400 },
	{ 0,   6500 },
	{ 0,  12700 },
	{ 0,  25000 },
	{ 0,  50000 },
	{ 0, 100000 },
	{ 0, 200000 },
	{ 0, 400000 },
	{ 0, 800000 },
};

/*
 * Conversion time is integration time + time to set register
 * this is used as integration time.
 */
static const int opt4060_int_time_reg[][2] = {
	{    600,  OPT4060_CTRL_CONVERSION_0_6MS  },
	{   1000,  OPT4060_CTRL_CONVERSION_1MS    },
	{   1800,  OPT4060_CTRL_CONVERSION_1_8MS  },
	{   3400,  OPT4060_CTRL_CONVERSION_3_4MS  },
	{   6500,  OPT4060_CTRL_CONVERSION_6_5MS  },
	{  12700,  OPT4060_CTRL_CONVERSION_12_7MS },
	{  25000,  OPT4060_CTRL_CONVERSION_25MS   },
	{  50000,  OPT4060_CTRL_CONVERSION_50MS   },
	{ 100000,  OPT4060_CTRL_CONVERSION_100MS  },
	{ 200000,  OPT4060_CTRL_CONVERSION_200MS  },
	{ 400000,  OPT4060_CTRL_CONVERSION_400MS  },
	{ 800000,  OPT4060_CTRL_CONVERSION_800MS  },
};

static int opt4060_als_time_to_index(const u32 als_integration_time)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(opt4060_int_time_available); i++) {
		if (als_integration_time == opt4060_int_time_available[i][1])
			return i;
	}

	return -EINVAL;
}

static u8 opt4060_calculate_crc(u8 exp, u32 mantissa, u8 count)
{
	u8 crc;

	/*
	 * Calculates a 4-bit CRC from a 20-bit mantissa, 4-bit exponent and a 4-bit counter.
	 * crc[0] = XOR(mantissa[19:0], exp[3:0], count[3:0])
	 * crc[1] = XOR(mantissa[1,3,5,7,9,11,13,15,17,19], exp[1,3], count[1,3])
	 * crc[2] = XOR(mantissa[3,7,11,15,19], exp[3], count[3])
	 * crc[3] = XOR(mantissa[3,11,19])
	 */
	crc = (hweight32(mantissa) + hweight32(exp) + hweight32(count)) % 2;
	crc |= ((hweight32(mantissa & 0xAAAAA) + hweight32(exp & 0xA)
		 + hweight32(count & 0xA)) % 2) << 1;
	crc |= ((hweight32(mantissa & 0x88888) + hweight32(exp & 0x8)
		 + hweight32(count & 0x8)) % 2) << 2;
	crc |= (hweight32(mantissa & 0x80808) % 2) << 3;

	return crc;
}

static int opt4060_set_int_state(struct opt4060_chip *chip, u32 state)
{
	int ret;
	unsigned int regval;

	guard(mutex)(&chip->irq_setting_lock);

	regval = FIELD_PREP(OPT4060_INT_CTRL_INT_CFG, state);
	ret = regmap_update_bits(chip->regmap, OPT4060_INT_CTRL,
				 OPT4060_INT_CTRL_INT_CFG, regval);
	if (ret)
		dev_err(chip->dev, "Failed to set interrupt config\n");
	return ret;
}

static int opt4060_set_sampling_mode(struct opt4060_chip *chip,
				     bool continuous)
{
	unsigned int reg;
	int ret;

	ret = regmap_read(chip->regmap, OPT4060_CTRL, &reg);
	if (ret < 0) {
		dev_err(chip->dev, "Failed to read ctrl register\n");
		return ret;
	}
	reg &= ~OPT4060_CTRL_OPER_MODE_MASK;
	if (continuous)
		reg |= FIELD_PREP(OPT4060_CTRL_OPER_MODE_MASK,
				  OPT4060_CTRL_OPER_MODE_CONTINUOUS);
	else
		reg |= FIELD_PREP(OPT4060_CTRL_OPER_MODE_MASK,
				  OPT4060_CTRL_OPER_MODE_ONE_SHOT);

	/*
	 * Trigger a new conversions by writing to CRTL register. It is not
	 * possible to use regmap_update_bits() since that will only write when
	 * data is modified.
	 */
	ret = regmap_write(chip->regmap, OPT4060_CTRL, reg);
	if (ret)
		dev_err(chip->dev, "Failed to set ctrl register\n");
	return ret;
}

static bool opt4060_event_active(struct opt4060_chip *chip)
{
	return chip->thresh_event_lo_active || chip->thresh_event_hi_active;
}

static int opt4060_set_state_common(struct opt4060_chip *chip,
				    bool continuous_sampling,
				    bool continuous_irq)
{
	int ret = 0;

	/* It is important to setup irq before sampling to avoid missing samples. */
	if (continuous_irq)
		ret = opt4060_set_int_state(chip, OPT4060_INT_CTRL_ALL_CH);
	else
		ret = opt4060_set_int_state(chip, OPT4060_INT_CTRL_THRESHOLD);
	if (ret) {
		dev_err(chip->dev, "Failed to set irq state.\n");
		return ret;
	}

	if (continuous_sampling || opt4060_event_active(chip))
		ret = opt4060_set_sampling_mode(chip, true);
	else
		ret = opt4060_set_sampling_mode(chip, false);
	if (ret)
		dev_err(chip->dev, "Failed to set sampling state.\n");
	return ret;
}

/*
 * Function for setting the driver state for sampling and irq. Either direct
 * mode of buffer mode will be claimed during the transition to prevent races
 * between sysfs read, buffer or events.
 */
static int opt4060_set_driver_state(struct iio_dev *indio_dev,
				    bool continuous_sampling,
				    bool continuous_irq)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);
	int ret = 0;
any_mode_retry:
	if (iio_device_claim_buffer_mode(indio_dev)) {
		/*
		 * This one is a *bit* hacky. If we cannot claim buffer mode,
		 * then try direct mode so that we make sure things cannot
		 * concurrently change. And we just keep trying until we get one
		 * of the modes...
		 */
		if (iio_device_claim_direct_mode(indio_dev))
			goto any_mode_retry;
		/*
		 * This path means that we managed to claim direct mode. In
		 * this case the buffer isn't enabled and it's okay to leave
		 * continuous mode for sampling and/or irq.
		 */
		ret = opt4060_set_state_common(chip, continuous_sampling,
					       continuous_irq);
		iio_device_release_direct_mode(indio_dev);
	} else {
		/*
		 * This path means that we managed to claim buffer mode. In
		 * this case the buffer is enabled and irq and sampling must go
		 * to or remain continuous, but only if the trigger is from this
		 * device.
		 */
		if (!iio_trigger_validate_own_device(indio_dev->trig, indio_dev))
			ret = opt4060_set_state_common(chip, true, true);
		else
			ret = opt4060_set_state_common(chip, continuous_sampling,
						       continuous_irq);
		iio_device_release_buffer_mode(indio_dev);
	}
	return ret;
}

/*
 * This function is called with framework mutex locked.
 */
static int opt4060_trigger_set_state(struct iio_trigger *trig, bool state)
{
	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
	struct opt4060_chip *chip = iio_priv(indio_dev);

	return opt4060_set_state_common(chip, state, state);
}

static int opt4060_read_raw_value(struct opt4060_chip *chip,
				  unsigned long address, u32 *raw)
{
	int ret;
	u16 result[2];
	u32 mantissa_raw;
	u16 msb, lsb;
	u8 exp, count, crc, calc_crc;

	ret = regmap_bulk_read(chip->regmap, address, result, 2);
	if (ret) {
		dev_err(chip->dev, "Reading channel data failed\n");
		return ret;
	}
	exp = FIELD_GET(OPT4060_EXPONENT_MASK, result[0]);
	msb = FIELD_GET(OPT4060_MSB_MASK, result[0]);
	count = FIELD_GET(OPT4060_COUNTER_MASK, result[1]);
	crc = FIELD_GET(OPT4060_CRC_MASK, result[1]);
	lsb = FIELD_GET(OPT4060_LSB_MASK, result[1]);
	mantissa_raw = (msb << 8) + lsb;
	calc_crc = opt4060_calculate_crc(exp, mantissa_raw, count);
	if (calc_crc != crc)
		return -EIO;
	*raw = mantissa_raw << exp;
	return 0;
}

static int opt4060_trigger_new_samples(struct iio_dev *indio_dev)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);
	int ret;

	/*
	 * The conversion time should be 500us startup time plus the integration time
	 * times the number of channels. An exact timeout isn't critical, it's better
	 * not to get incorrect errors in the log. Setting the timeout to double the
	 * theoretical time plus and extra 100ms margin.
	 */
	unsigned int timeout_us = (500 + OPT4060_NUM_CHANS *
				  opt4060_int_time_reg[chip->int_time][0]) * 2 + 100000;

	/* Setting the state in one shot mode with irq on each sample. */
	ret = opt4060_set_driver_state(indio_dev, false, true);
	if (ret)
		return ret;

	if (chip->irq) {
		guard(mutex)(&chip->irq_setting_lock);
		reinit_completion(&chip->completion);
		if (wait_for_completion_timeout(&chip->completion,
						usecs_to_jiffies(timeout_us)) == 0) {
			dev_err(chip->dev, "Completion timed out.\n");
			return -ETIME;
		}
	} else {
		unsigned int ready;

		ret = regmap_read_poll_timeout(chip->regmap, OPT4060_RES_CTRL,
					       ready, (ready & OPT4060_RES_CTRL_CONV_READY),
					       1000, timeout_us);
		if (ret)
			dev_err(chip->dev, "Conversion ready did not finish within timeout.\n");
	}
	/* Setting the state in one shot mode with irq on thresholds. */
	return opt4060_set_driver_state(indio_dev, false, false);
}

static int opt4060_read_chan_raw(struct iio_dev *indio_dev,
				 struct iio_chan_spec const *chan, int *val)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);
	u32 adc_raw;
	int ret;

	ret = opt4060_trigger_new_samples(indio_dev);
	if (ret) {
		dev_err(chip->dev, "Failed to trigger new samples.\n");
		return ret;
	}

	ret = opt4060_read_raw_value(chip, chan->address, &adc_raw);
	if (ret) {
		dev_err(chip->dev, "Reading raw channel data failed.\n");
		return ret;
	}
	*val = adc_raw;
	return IIO_VAL_INT;
}

/*
 * Returns the scale values used for red, green and blue. Scales the raw value
 * so that for a particular test light source, typically white, the measurement
 * intensity is the same across different color channels.
 */
static int opt4060_get_chan_scale(struct iio_dev *indio_dev,
				  struct iio_chan_spec const *chan,
				  int *val, int *val2)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);

	switch (chan->scan_index) {
	case OPT4060_RED:
		/* 2.4 */
		*val = 2;
		*val2 = 400000;
		break;
	case OPT4060_GREEN:
		/* 1.0 */
		*val = 1;
		*val2 = 0;
		break;
	case OPT4060_BLUE:
		/* 1.3 */
		*val = 1;
		*val2 = 300000;
		break;
	default:
		dev_err(chip->dev, "Unexpected channel index.\n");
		return -EINVAL;
	}
	return IIO_VAL_INT_PLUS_MICRO;
}

static int opt4060_calc_illuminance(struct opt4060_chip *chip, int *val)
{
	u32 lux_raw;
	int ret;

	/* The green wide spectral channel is used for illuminance. */
	ret = opt4060_read_raw_value(chip, OPT4060_GREEN_MSB, &lux_raw);
	if (ret) {
		dev_err(chip->dev, "Reading raw channel data failed\n");
		return ret;
	}

	/* Illuminance is calculated by ADC_RAW * 2.15e-3. */
	*val = DIV_U64_ROUND_CLOSEST((u64)(lux_raw * 215), 1000);
	return ret;
}

static int opt4060_read_illuminance(struct iio_dev *indio_dev,
				    struct iio_chan_spec const *chan,
				    int *val)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);
	int ret;

	ret = opt4060_trigger_new_samples(indio_dev);
	if (ret) {
		dev_err(chip->dev, "Failed to trigger new samples.\n");
		return ret;
	}
	ret = opt4060_calc_illuminance(chip, val);
	if (ret) {
		dev_err(chip->dev, "Failed to calculate illuminance.\n");
		return ret;
	}

	return IIO_VAL_INT;
}

static int opt4060_set_int_time(struct opt4060_chip *chip)
{
	unsigned int regval;
	int ret;

	regval = FIELD_PREP(OPT4060_CTRL_CONV_TIME_MASK, chip->int_time);
	ret = regmap_update_bits(chip->regmap, OPT4060_CTRL,
				 OPT4060_CTRL_CONV_TIME_MASK, regval);
	if (ret)
		dev_err(chip->dev, "Failed to set integration time.\n");

	return ret;
}

static int opt4060_power_down(struct opt4060_chip *chip)
{
	int ret;

	ret = regmap_clear_bits(chip->regmap, OPT4060_CTRL, OPT4060_CTRL_OPER_MODE_MASK);
	if (ret)
		dev_err(chip->dev, "Failed to power down\n");

	return ret;
}

static void opt4060_chip_off_action(void *chip)
{
	opt4060_power_down(chip);
}

#define _OPT4060_COLOR_CHANNEL(_color, _mask, _ev_spec, _num_ev_spec)		\
{										\
	.type = IIO_INTENSITY,							\
	.modified = 1,								\
	.channel2 = IIO_MOD_LIGHT_##_color,					\
	.info_mask_separate = _mask,						\
	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),			\
	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),	\
	.address = OPT4060_##_color##_MSB,					\
	.scan_index = OPT4060_##_color,						\
	.scan_type = {								\
		.sign = 'u',							\
		.realbits = 32,							\
		.storagebits = 32,						\
		.endianness = IIO_CPU,						\
	},									\
	.event_spec = _ev_spec,							\
	.num_event_specs = _num_ev_spec,					\
}

#define OPT4060_COLOR_CHANNEL(_color, _mask)					\
	_OPT4060_COLOR_CHANNEL(_color, _mask, opt4060_event_spec,		\
			       ARRAY_SIZE(opt4060_event_spec))			\

#define OPT4060_COLOR_CHANNEL_NO_EVENTS(_color, _mask)				\
	_OPT4060_COLOR_CHANNEL(_color, _mask, NULL, 0)				\

#define OPT4060_LIGHT_CHANNEL(_channel)						\
{										\
	.type = IIO_LIGHT,							\
	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),			\
	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),			\
	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),	\
	.scan_index = OPT4060_##_channel,					\
	.scan_type = {								\
		.sign = 'u',							\
		.realbits = 32,							\
		.storagebits = 32,						\
		.endianness = IIO_CPU,						\
	},									\
}

static const struct iio_event_spec opt4060_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),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_EITHER,
		.mask_separate = BIT(IIO_EV_INFO_PERIOD),
	},
};

static const struct iio_chan_spec opt4060_channels[] = {
	OPT4060_COLOR_CHANNEL(RED, BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)),
	OPT4060_COLOR_CHANNEL(GREEN, BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)),
	OPT4060_COLOR_CHANNEL(BLUE, BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)),
	OPT4060_COLOR_CHANNEL(CLEAR, BIT(IIO_CHAN_INFO_RAW)),
	OPT4060_LIGHT_CHANNEL(ILLUM),
	IIO_CHAN_SOFT_TIMESTAMP(OPT4060_NUM_CHANS),
};

static const struct iio_chan_spec opt4060_channels_no_events[] = {
	OPT4060_COLOR_CHANNEL_NO_EVENTS(RED, BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)),
	OPT4060_COLOR_CHANNEL_NO_EVENTS(GREEN, BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)),
	OPT4060_COLOR_CHANNEL_NO_EVENTS(BLUE, BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)),
	OPT4060_COLOR_CHANNEL_NO_EVENTS(CLEAR, BIT(IIO_CHAN_INFO_RAW)),
	OPT4060_LIGHT_CHANNEL(ILLUM),
	IIO_CHAN_SOFT_TIMESTAMP(OPT4060_NUM_CHANS),
};

static int opt4060_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long mask)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		return opt4060_read_chan_raw(indio_dev, chan, val);
	case IIO_CHAN_INFO_SCALE:
		return opt4060_get_chan_scale(indio_dev, chan, val, val2);
	case IIO_CHAN_INFO_PROCESSED:
		return opt4060_read_illuminance(indio_dev, chan, val);
	case IIO_CHAN_INFO_INT_TIME:
		*val = 0;
		*val2 = opt4060_int_time_reg[chip->int_time][0];
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static int opt4060_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct opt4060_chip *chip = iio_priv(indio_dev);
	int int_time;

	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
		int_time = opt4060_als_time_to_index(val2);
		if (int_time < 0)
			return int_time;
		chip->int_time = int_time;
		return opt4060_set_int_time(chip);
	default:
		return -EINVAL;
	}
}

static int opt4060_write_raw_get_fmt(struct iio_dev *indio_dev,
				     struct iio_chan_spec const *chan,
				     long mask)
{
	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static u32 opt4060_calc_th_reg(u32 adc_val)
{
	u32 th_val, th_exp, bits;
	/*
	 * The threshold registers take 4 bits of exponent and 12 bits of data
	 * ADC = TH_VAL << (8 + TH_EXP)
	 */
	bits = fls(adc_val);

	if (bits > 31)
		th_exp = 11; /* Maximum exponent */
	else if (bits > 20)
		th_exp = bits - 20;
	else
		th_exp = 0;
	th_val = (adc_val >> (8 + th_exp)) & 0xfff;

	return (th_exp << 12) + th_val;
}

static u32 opt4060_calc_val_from_th_reg(u32 th_reg)
{
	/*
	 * The threshold registers take 4 bits of exponent and 12 bits of data
	 * ADC = TH_VAL << (8 + TH_EXP)
	 */
	u32 th_val, th_exp;

	th_exp = (th_reg >> 12) & 0xf;
	th_val = th_reg & 0xfff;

	return th_val << (8 + th_exp);
}

static int opt4060_read_available(struct iio_dev *indio_dev,
				  struct iio_chan_spec const *chan,
				  const int **vals, int *type, int *length,
				  long mask)
{
	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
		*length = ARRAY_SIZE(opt4060_int_time_available) * 2;
		*vals = (const int *)opt4060_int_time_available;
		*type = IIO_VAL_INT_PLUS_MICRO;
		return IIO_AVAIL_LIST;

	default:
		return -EINVAL;
	}
}

static ssize_t opt4060_read_ev_period(struct opt4060_chip *chip, int *val,
				      int *val2)
{
	int ret, pers, fault_count, int_time;
	u64 uval;

	int_time = opt4060_int_time_reg[chip->int_time][0];

	ret = regmap_read(chip->regmap, OPT4060_CTRL, &fault_count);
	if (ret < 0)
		return ret;

	fault_count = fault_count & OPT4060_CTRL_FAULT_COUNT_MASK;
	switch (fault_count) {
	case OPT4060_CTRL_FAULT_COUNT_2:
		pers = 2;
		break;
	case OPT4060_CTRL_FAULT_COUNT_4:
		pers = 4;
		break;
	case OPT4060_CTRL_FAULT_COUNT_8:
		pers = 8;
		break;

	default:
		pers = 1;
		break;
	}

	uval = mul_u32_u32(int_time, pers);
	*val = div_u64_rem(uval, MICRO, val2);

	return IIO_VAL_INT_PLUS_MICRO;
}

static ssize_t opt4060_write_ev_period(struct opt4060_chip *chip, int val,
				       int val2)
{
	u64 uval, int_time;
	unsigned int regval, fault_count_val;

	uval = mul_u32_u32(val, MICRO) + val2;
	int_time = opt4060_int_time_reg[chip->int_time][0];

	/* Check if the period is closest to 1, 2, 4 or 8 times integration time.*/
	if (uval <= int_time)
		fault_count_val = OPT4060_CTRL_FAULT_COUNT_1;
	else if (uval <= int_time * 2)
		fault_count_val = OPT4060_CTRL_FAULT_COUNT_2;
	else if (uval <= int_time * 4)
		fault_count_val = OPT4060_CTRL_FAULT_COUNT_4;
	else
		fault_count_val = OPT4060_CTRL_FAULT_COUNT_8;

	regval = FIELD_PREP(OPT4060_CTRL_FAULT_COUNT_MASK, fault_count_val);
	return regmap_update_bits(chip->regmap, OPT4060_CTRL,
				 OPT4060_CTRL_FAULT_COUNT_MASK, regval);
}

static int opt4060_get_channel_sel(struct opt4060_chip *chip, int *ch_sel)
{
	int ret;
	u32 regval;

	ret = regmap_read(chip->regmap, OPT4060_INT_CTRL, &regval);
	if (ret) {
		dev_err(chip->dev, "Failed to get channel selection.\n");
		return ret;
	}
	*ch_sel = FIELD_GET(OPT4060_INT_CTRL_THRESH_SEL, regval);
	return ret;
}

static int opt4060_set_channel_sel(struct opt4060_chip *chip, int ch_sel)
{
	int ret;
	u32 regval;

	regval = FIELD_PREP(OPT4060_INT_CTRL_THRESH_SEL, ch_sel);
	ret = regmap_update_bits(chip->regmap, OPT4060_INT_CTRL,
				 OPT4060_INT_CTRL_THRESH_SEL, regval);
	if (ret)
		dev_err(chip->dev, "Failed to set channel selection.\n");
	return ret;
}

static int opt4060_get_thresholds(struct opt4060_chip *chip, u32 *th_lo, u32 *th_hi)
{
	int ret;
	u32 regval;

	ret = regmap_read(chip->regmap, OPT4060_THRESHOLD_LOW, &regval);
	if (ret) {
		dev_err(chip->dev, "Failed to read THRESHOLD_LOW.\n");
		return ret;
	}
	*th_lo = opt4060_calc_val_from_th_reg(regval);

	ret = regmap_read(chip->regmap, OPT4060_THRESHOLD_HIGH, &regval);
	if (ret) {
		dev_err(chip->dev, "Failed to read THRESHOLD_LOW.\n");
		return ret;
	}
	*th_hi = opt4060_calc_val_from_th_reg(regval);

	return ret;
}

static int opt4060_set_thresholds(struct opt4060_chip *chip, u32 th_lo, u32 th_hi)
{
	int ret;

	ret = regmap_write(chip->regmap, OPT4060_THRESHOLD_LOW, opt4060_calc_th_reg(th_lo));
	if (ret) {
		dev_err(chip->dev, "Failed to write THRESHOLD_LOW.\n");
		return ret;
	}

	ret = regmap_write(chip->regmap, OPT4060_THRESHOLD_HIGH, opt4060_calc_th_reg(th_hi));
	if (ret)
		dev_err(chip->dev, "Failed to write THRESHOLD_HIGH.\n");

	return ret;
}

static int opt4060_read_event(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 opt4060_chip *chip = iio_priv(indio_dev);
	u32 th_lo, th_hi;
	int ret;

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

	switch (info) {
	case IIO_EV_INFO_VALUE:
		ret = opt4060_get_thresholds(chip, &th_lo, &th_hi);
		if (ret)
			return ret;
		if (dir == IIO_EV_DIR_FALLING) {
			*val = th_lo;
			ret = IIO_VAL_INT;
		} else if (dir == IIO_EV_DIR_RISING) {
			*val = th_hi;
			ret = IIO_VAL_INT;
		}
		return ret;
	case IIO_EV_INFO_PERIOD:
		return opt4060_read_ev_period(chip, val, val2);
	default:
		return -EINVAL;
	}
}

static int opt4060_write_event(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 opt4060_chip *chip = iio_priv(indio_dev);
	u32 th_lo, th_hi;
	int ret;

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

	switch (info) {
	case IIO_EV_INFO_VALUE:
		ret = opt4060_get_thresholds(chip, &th_lo, &th_hi);
		if (ret)
			return ret;
		if (dir == IIO_EV_DIR_FALLING)
			th_lo = val;
		else if (dir == IIO_EV_DIR_RISING)
			th_hi = val;
		return opt4060_set_thresholds(chip, th_lo, th_hi);
	case IIO_EV_INFO_PERIOD:
		return opt4060_write_ev_period(chip, val, val2);
	default:
		return -EINVAL;
	}
}

static int opt4060_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 ch_sel, ch_idx = chan->scan_index;
	struct opt4060_chip *chip = iio_priv(indio_dev);
	int ret;

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

	ret = opt4060_get_channel_sel(chip, &ch_sel);
	if (ret)
		return ret;

	if (((dir == IIO_EV_DIR_FALLING) && chip->thresh_event_lo_active) ||
	    ((dir == IIO_EV_DIR_RISING) && chip->thresh_event_hi_active))
		return ch_sel == ch_idx;

	return ret;
}

static int opt4060_write_event_config(struct iio_dev *indio_dev,
				      const struct iio_chan_spec *chan,
				      enum iio_event_type type,
				      enum iio_event_direction dir, bool state)
{
	int ch_sel, ch_idx = chan->scan_index;
	struct opt4060_chip *chip = iio_priv(indio_dev);
	int ret;

	guard(mutex)(&chip->event_enabling_lock);

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

	ret = opt4060_get_channel_sel(chip, &ch_sel);
	if (ret)
		return ret;

	if (state) {
		/* Only one channel can be active at the same time */
		if ((chip->thresh_event_lo_active || chip->thresh_event_hi_active) &&
		    (ch_idx != ch_sel))
			return -EBUSY;
		if (dir == IIO_EV_DIR_FALLING)
			chip->thresh_event_lo_active = true;
		else if (dir == IIO_EV_DIR_RISING)
			chip->thresh_event_hi_active = true;
		ret = opt4060_set_channel_sel(chip, ch_idx);
		if (ret)
			return ret;
	} else {
		if (ch_idx == ch_sel) {
			if (dir == IIO_EV_DIR_FALLING)
				chip->thresh_event_lo_active = false;
			else if (dir == IIO_EV_DIR_RISING)
				chip->thresh_event_hi_active = false;
		}
	}

	return opt4060_set_driver_state(indio_dev,
					chip->thresh_event_hi_active |
					chip->thresh_event_lo_active,
					false);
}

static const struct iio_info opt4060_info = {
	.read_raw = opt4060_read_raw,
	.write_raw = opt4060_write_raw,
	.write_raw_get_fmt = opt4060_write_raw_get_fmt,
	.read_avail = opt4060_read_available,
	.read_event_value = opt4060_read_event,
	.write_event_value = opt4060_write_event,
	.read_event_config = opt4060_read_event_config,
	.write_event_config = opt4060_write_event_config,
};

static const struct iio_info opt4060_info_no_irq = {
	.read_raw = opt4060_read_raw,
	.write_raw = opt4060_write_raw,
	.write_raw_get_fmt = opt4060_write_raw_get_fmt,
	.read_avail = opt4060_read_available,
};

static int opt4060_load_defaults(struct opt4060_chip *chip)
{
	u16 reg;
	int ret;

	chip->int_time = OPT4060_DEFAULT_CONVERSION_TIME;

	/* Set initial MIN/MAX thresholds */
	ret = opt4060_set_thresholds(chip, 0, UINT_MAX);
	if (ret)
		return ret;

	/*
	 * Setting auto-range, latched window for thresholds, one-shot conversion
	 * and quick wake-up mode as default.
	 */
	reg = FIELD_PREP(OPT4060_CTRL_RANGE_MASK,
			 OPT4060_CTRL_LIGHT_SCALE_AUTO);
	reg |= FIELD_PREP(OPT4060_CTRL_CONV_TIME_MASK, chip->int_time);
	reg |= FIELD_PREP(OPT4060_CTRL_OPER_MODE_MASK,
				OPT4060_CTRL_OPER_MODE_ONE_SHOT);
	reg |= OPT4060_CTRL_QWAKE_MASK | OPT4060_CTRL_LATCH_MASK;

	ret = regmap_write(chip->regmap, OPT4060_CTRL, reg);
	if (ret)
		dev_err(chip->dev, "Failed to set configuration\n");

	return ret;
}

static bool opt4060_volatile_reg(struct device *dev, unsigned int reg)
{
	return reg <= OPT4060_CLEAR_LSB || reg == OPT4060_RES_CTRL;
}

static bool opt4060_writable_reg(struct device *dev, unsigned int reg)
{
	return reg >= OPT4060_THRESHOLD_LOW || reg >= OPT4060_INT_CTRL;
}

static bool opt4060_readonly_reg(struct device *dev, unsigned int reg)
{
	return reg == OPT4060_DEVICE_ID;
}

static bool opt4060_readable_reg(struct device *dev, unsigned int reg)
{
	/* Volatile, writable and read-only registers are readable. */
	return opt4060_volatile_reg(dev, reg) || opt4060_writable_reg(dev, reg) ||
	       opt4060_readonly_reg(dev, reg);
}

static const struct regmap_config opt4060_regmap_config = {
	.name = "opt4060",
	.reg_bits = 8,
	.val_bits = 16,
	.cache_type = REGCACHE_RBTREE,
	.max_register = OPT4060_DEVICE_ID,
	.readable_reg = opt4060_readable_reg,
	.writeable_reg = opt4060_writable_reg,
	.volatile_reg = opt4060_volatile_reg,
	.val_format_endian = REGMAP_ENDIAN_BIG,
};

static const struct iio_trigger_ops opt4060_trigger_ops = {
	.set_trigger_state = opt4060_trigger_set_state,
};

static irqreturn_t opt4060_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *idev = pf->indio_dev;
	struct opt4060_chip *chip = iio_priv(idev);
	struct  {
		u32 chan[OPT4060_NUM_CHANS];
		aligned_s64 ts;
	} raw;
	int i = 0;
	int chan, ret;

	/* If the trigger is not from this driver, a new sample is needed.*/
	if (iio_trigger_validate_own_device(idev->trig, idev))
		opt4060_trigger_new_samples(idev);

	memset(&raw, 0, sizeof(raw));

	iio_for_each_active_channel(idev, chan) {
		if (chan == OPT4060_ILLUM)
			ret = opt4060_calc_illuminance(chip, &raw.chan[i++]);
		else
			ret = opt4060_read_raw_value(chip,
						     idev->channels[chan].address,
						     &raw.chan[i++]);
		if (ret) {
			dev_err(chip->dev, "Reading channel data failed\n");
			goto err_read;
		}
	}

	iio_push_to_buffers_with_timestamp(idev, &raw, pf->timestamp);
err_read:
	iio_trigger_notify_done(idev->trig);
	return IRQ_HANDLED;
}

static irqreturn_t opt4060_irq_thread(int irq, void *private)
{
	struct iio_dev *idev = private;
	struct opt4060_chip *chip = iio_priv(idev);
	int ret, dummy;
	unsigned int int_res;

	ret = regmap_read(chip->regmap, OPT4060_RES_CTRL, &int_res);
	if (ret < 0) {
		dev_err(chip->dev, "Failed to read interrupt reasons.\n");
		return IRQ_NONE;
	}

	/* Read OPT4060_CTRL to clear interrupt */
	ret = regmap_read(chip->regmap, OPT4060_CTRL, &dummy);
	if (ret < 0) {
		dev_err(chip->dev, "Failed to clear interrupt\n");
		return IRQ_NONE;
	}

	/* Handle events */
	if (int_res & (OPT4060_RES_CTRL_FLAG_H | OPT4060_RES_CTRL_FLAG_L)) {
		u64 code;
		int chan = 0;

		ret = opt4060_get_channel_sel(chip, &chan);
		if (ret) {
			dev_err(chip->dev, "Failed to read threshold channel.\n");
			return IRQ_NONE;
		}

		/* Check if the interrupt is from the lower threshold */
		if (int_res & OPT4060_RES_CTRL_FLAG_L) {
			code = IIO_MOD_EVENT_CODE(IIO_INTENSITY,
						  chan,
						  idev->channels[chan].channel2,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_FALLING);
			iio_push_event(idev, code, iio_get_time_ns(idev));
		}
		/* Check if the interrupt is from the upper threshold */
		if (int_res & OPT4060_RES_CTRL_FLAG_H) {
			code = IIO_MOD_EVENT_CODE(IIO_INTENSITY,
						  chan,
						  idev->channels[chan].channel2,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING);
			iio_push_event(idev, code, iio_get_time_ns(idev));
		}
	}

	/* Handle conversion ready */
	if (int_res & OPT4060_RES_CTRL_CONV_READY) {
		/* Signal completion for potentially waiting reads */
		complete(&chip->completion);

		/* Handle data ready triggers */
		if (iio_buffer_enabled(idev))
			iio_trigger_poll_nested(chip->trig);
	}
	return IRQ_HANDLED;
}

static int opt4060_setup_buffer(struct opt4060_chip *chip, struct iio_dev *idev)
{
	int ret;

	ret = devm_iio_triggered_buffer_setup(chip->dev, idev,
					      &iio_pollfunc_store_time,
					      opt4060_trigger_handler, NULL);
	if (ret)
		return dev_err_probe(chip->dev, ret,
				     "Buffer setup failed.\n");
	return ret;
}

static int opt4060_setup_trigger(struct opt4060_chip *chip, struct iio_dev *idev)
{
	struct iio_trigger *data_trigger;
	char *name;
	int ret;

	data_trigger = devm_iio_trigger_alloc(chip->dev, "%s-data-ready-dev%d",
					      idev->name, iio_device_id(idev));
	if (!data_trigger)
		return -ENOMEM;

	/*
	 * The data trigger allows for sample capture on each new conversion
	 * ready interrupt.
	 */
	chip->trig = data_trigger;
	data_trigger->ops = &opt4060_trigger_ops;
	iio_trigger_set_drvdata(data_trigger, idev);
	ret = devm_iio_trigger_register(chip->dev, data_trigger);
	if (ret)
		return dev_err_probe(chip->dev, ret,
				     "Data ready trigger registration failed\n");

	name = devm_kasprintf(chip->dev, GFP_KERNEL, "%s-opt4060",
			      dev_name(chip->dev));
	if (!name)
		return dev_err_probe(chip->dev, -ENOMEM, "Failed to alloc chip name\n");

	ret = devm_request_threaded_irq(chip->dev, chip->irq, NULL, opt4060_irq_thread,
					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
					name, idev);
	if (ret)
		return dev_err_probe(chip->dev, ret, "Could not request IRQ\n");

	init_completion(&chip->completion);

	ret = devm_mutex_init(chip->dev, &chip->irq_setting_lock);
	if (ret)
		return ret;

	ret = devm_mutex_init(chip->dev, &chip->event_enabling_lock);
	if (ret)
		return ret;

	ret = regmap_write_bits(chip->regmap, OPT4060_INT_CTRL,
				OPT4060_INT_CTRL_OUTPUT,
				OPT4060_INT_CTRL_OUTPUT);
	if (ret)
		return dev_err_probe(chip->dev, ret,
				     "Failed to set interrupt as output\n");

	return 0;
}

static int opt4060_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct opt4060_chip *chip;
	struct iio_dev *indio_dev;
	int ret;
	unsigned int regval, dev_id;

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

	chip = iio_priv(indio_dev);

	ret = devm_regulator_get_enable(dev, "vdd");
	if (ret)
		return dev_err_probe(dev, ret, "Failed to enable vdd supply\n");

	chip->regmap = devm_regmap_init_i2c(client, &opt4060_regmap_config);
	if (IS_ERR(chip->regmap))
		return dev_err_probe(dev, PTR_ERR(chip->regmap),
				     "regmap initialization failed\n");

	chip->dev = dev;
	chip->irq = client->irq;

	ret = regmap_reinit_cache(chip->regmap, &opt4060_regmap_config);
	if (ret)
		return dev_err_probe(dev, ret,
				     "failed to reinit regmap cache\n");

	ret = regmap_read(chip->regmap, OPT4060_DEVICE_ID, &regval);
	if (ret < 0)
		return dev_err_probe(dev, ret,
			"Failed to read the device ID register\n");

	dev_id = FIELD_GET(OPT4060_DEVICE_ID_MASK, regval);
	if (dev_id != OPT4060_DEVICE_ID_VAL)
		dev_info(dev, "Device ID: %#04x unknown\n", dev_id);

	if (chip->irq) {
		indio_dev->info = &opt4060_info;
		indio_dev->channels = opt4060_channels;
		indio_dev->num_channels = ARRAY_SIZE(opt4060_channels);
	} else {
		indio_dev->info = &opt4060_info_no_irq;
		indio_dev->channels = opt4060_channels_no_events;
		indio_dev->num_channels = ARRAY_SIZE(opt4060_channels_no_events);
	}
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->name = "opt4060";

	ret = opt4060_load_defaults(chip);
	if (ret < 0)
		return dev_err_probe(dev, ret,
				     "Failed to set sensor defaults\n");

	ret = devm_add_action_or_reset(dev, opt4060_chip_off_action, chip);
	if (ret < 0)
		return dev_err_probe(dev, ret,
				     "Failed to setup power off action\n");

	ret = opt4060_setup_buffer(chip, indio_dev);
	if (ret)
		return ret;

	if (chip->irq) {
		ret = opt4060_setup_trigger(chip, indio_dev);
		if (ret)
			return ret;
	}

	return devm_iio_device_register(dev, indio_dev);
}

static const struct i2c_device_id opt4060_id[] = {
	{ "opt4060", },
	{ }
};
MODULE_DEVICE_TABLE(i2c, opt4060_id);

static const struct of_device_id opt4060_of_match[] = {
	{ .compatible = "ti,opt4060" },
	{ }
};
MODULE_DEVICE_TABLE(of, opt4060_of_match);

static struct i2c_driver opt4060_driver = {
	.driver = {
		.name = "opt4060",
		.of_match_table = opt4060_of_match,
	},
	.probe = opt4060_probe,
	.id_table = opt4060_id,
};
module_i2c_driver(opt4060_driver);

MODULE_AUTHOR("Per-Daniel Olsson <[email protected]>");
MODULE_DESCRIPTION("Texas Instruments OPT4060 RGBW color sensor driver");
MODULE_LICENSE("GPL");