path: root/drivers/iio/proximity/vl53l1x-i2c.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
/*
 * Support for ST VL53L1X FlightSense ToF Ranging Sensor on a i2c bus.
 *
 * Copyright (C) 2026 Siratul Islam <email@sirat.me>
 *
 * Datasheet available at
 * <https://www.st.com/resource/en/datasheet/vl53l1x.pdf>
 *
 * Default 7-bit i2c slave address 0x29.
 *
 * The VL53L1X requires a firmware configuration blob to be loaded at boot.
 * Register values for the default configuration are taken from
 * ST's VL53L1X Ultra Lite Driver (STSW-IMG009).
 */

#include <linux/array_size.h>
#include <linux/bits.h>
#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dev_printk.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/math.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/time.h>
#include <linux/types.h>

#include <asm/byteorder.h>

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

#define VL53L1X_REG_SOFT_RESET						0x0000
#define VL53L1X_REG_VHV_CONFIG__TIMEOUT_MACROP_LOOP_BOUND		0x0008
#define VL53L1X_REG_VHV_CONFIG__INIT					0x000B
#define VL53L1X_REG_GPIO_HV_MUX__CTRL					0x0030
#define VL53L1X_REG_GPIO__TIO_HV_STATUS					0x0031
#define VL53L1X_REG_SYSTEM__INTERRUPT_CONFIG_GPIO			0x0046
#define VL53L1X_REG_PHASECAL_CONFIG__TIMEOUT_MACROP			0x004B
#define VL53L1X_REG_RANGE_CONFIG__TIMEOUT_MACROP_A			0x005E
#define VL53L1X_REG_RANGE_CONFIG__VCSEL_PERIOD_A			0x0060
#define VL53L1X_REG_RANGE_CONFIG__TIMEOUT_MACROP_B			0x0061
#define VL53L1X_REG_RANGE_CONFIG__VCSEL_PERIOD_B			0x0063
#define VL53L1X_REG_RANGE_CONFIG__VALID_PHASE_HIGH			0x0069
#define VL53L1X_REG_SYSTEM__INTERMEASUREMENT_PERIOD			0x006C
#define VL53L1X_REG_SD_CONFIG__WOI_SD0					0x0078
#define VL53L1X_REG_SD_CONFIG__WOI_SD1					0x0079
#define VL53L1X_REG_SD_CONFIG__INITIAL_PHASE_SD0			0x007A
#define VL53L1X_REG_SD_CONFIG__INITIAL_PHASE_SD1			0x007B
#define VL53L1X_REG_SYSTEM__INTERRUPT_CLEAR				0x0086
#define VL53L1X_REG_SYSTEM__MODE_START					0x0087
#define VL53L1X_REG_RESULT__RANGE_STATUS				0x0089
#define VL53L1X_REG_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0	0x0096
#define VL53L1X_REG_RESULT__OSC_CALIBRATE_VAL				0x00DE
#define VL53L1X_REG_FIRMWARE__SYSTEM_STATUS				0x00E5
#define VL53L1X_REG_IDENTIFICATION__MODEL_ID				0x010F
#define VL53L1X_REG_DEFAULT_CONFIG					0x002D

#define VL53L1X_MODEL_ID_VAL		0xEACC

#define VL53L1X_MODE_START_TIMED	0x40
#define VL53L1X_MODE_START_STOP		0x00

#define VL53L1X_INT_NEW_SAMPLE_READY	0x02

#define VL53L1X_GPIO_HV_MUX_POLARITY	BIT(4)

#define VL53L1X_VHV_LOOP_BOUND_TWO	0x09

#define VL53L1X_RANGE_STATUS_MASK	GENMASK(4, 0)
#define VL53L1X_RANGE_STATUS_VALID	9

#define VL53L1X_OSC_CALIBRATE_MASK	GENMASK(9, 0)

/* Inter-measurement period uses PLL divider with 1.075 oscillator correction */
static const struct u32_fract vl53l1x_osc_correction = {
	.numerator = 1075,
	.denominator = 1000,
};

enum vl53l1x_distance_mode {
	VL53L1X_SHORT,
	VL53L1X_LONG,
};

struct vl53l1x_data {
	struct regmap *regmap;
	struct completion completion;
	struct reset_control *xshut_reset;
	enum vl53l1x_distance_mode distance_mode;
	u8 gpio_polarity;
	int irq;
};

static const struct regmap_range vl53l1x_volatile_ranges[] = {
	regmap_reg_range(VL53L1X_REG_GPIO__TIO_HV_STATUS,
			 VL53L1X_REG_GPIO__TIO_HV_STATUS),
	regmap_reg_range(VL53L1X_REG_RESULT__RANGE_STATUS,
			 VL53L1X_REG_RESULT__RANGE_STATUS),
	regmap_reg_range(VL53L1X_REG_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0,
			 VL53L1X_REG_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0 + 1),
	regmap_reg_range(VL53L1X_REG_RESULT__OSC_CALIBRATE_VAL,
			 VL53L1X_REG_RESULT__OSC_CALIBRATE_VAL + 1),
	regmap_reg_range(VL53L1X_REG_FIRMWARE__SYSTEM_STATUS,
			 VL53L1X_REG_FIRMWARE__SYSTEM_STATUS),
};

static const struct regmap_access_table vl53l1x_volatile_table = {
	.yes_ranges = vl53l1x_volatile_ranges,
	.n_yes_ranges = ARRAY_SIZE(vl53l1x_volatile_ranges),
};

static const struct regmap_range vl53l1x_write_only_ranges[] = {
	regmap_reg_range(VL53L1X_REG_SOFT_RESET, VL53L1X_REG_SOFT_RESET),
	regmap_reg_range(VL53L1X_REG_SYSTEM__INTERRUPT_CLEAR,
			 VL53L1X_REG_SYSTEM__MODE_START),
};

static const struct regmap_access_table vl53l1x_readable_table = {
	.no_ranges = vl53l1x_write_only_ranges,
	.n_no_ranges = ARRAY_SIZE(vl53l1x_write_only_ranges),
};

static const struct regmap_config vl53l1x_regmap_config = {
	.reg_bits = 16,
	.val_bits = 8,
	/* MODEL_ID is 16-bit. +1 covers the second byte at 0x0110 */
	.max_register = VL53L1X_REG_IDENTIFICATION__MODEL_ID + 1,
	.cache_type = REGCACHE_MAPLE,
	.volatile_table = &vl53l1x_volatile_table,
	.rd_table = &vl53l1x_readable_table,
};

static int vl53l1x_read_u16(struct vl53l1x_data *data, u16 reg, u16 *val)
{
	__be16 buf;
	int ret;

	ret = regmap_bulk_read(data->regmap, reg, &buf, sizeof(buf));
	if (ret)
		return ret;

	*val = be16_to_cpu(buf);
	return 0;
}

static int vl53l1x_write_u16(struct vl53l1x_data *data, u16 reg, u16 val)
{
	__be16 buf = cpu_to_be16(val);

	return regmap_bulk_write(data->regmap, reg, &buf, sizeof(buf));
}

static int vl53l1x_write_u32(struct vl53l1x_data *data, u16 reg, u32 val)
{
	__be32 buf = cpu_to_be32(val);

	return regmap_bulk_write(data->regmap, reg, &buf, sizeof(buf));
}

static int vl53l1x_clear_irq(struct vl53l1x_data *data)
{
	return regmap_write(data->regmap, VL53L1X_REG_SYSTEM__INTERRUPT_CLEAR, 0x01);
}

static int vl53l1x_start_ranging(struct vl53l1x_data *data)
{
	int ret;

	ret = vl53l1x_clear_irq(data);
	if (ret)
		return ret;

	return regmap_write(data->regmap, VL53L1X_REG_SYSTEM__MODE_START,
			    VL53L1X_MODE_START_TIMED);
}

static int vl53l1x_stop_ranging(struct vl53l1x_data *data)
{
	return regmap_write(data->regmap, VL53L1X_REG_SYSTEM__MODE_START,
			    VL53L1X_MODE_START_STOP);
}

/*
 * Default configuration blob from ST's VL53L1X Ultra Lite Driver
 * (STSW-IMG009).
 */
static const u8 vl53l1x_default_config[] = {
	0x00, 0x00, 0x00, 0x01, 0x02, 0x00, 0x02, 0x08,	/* reg 0x2d..0x34 */
	0x00, 0x08, 0x10, 0x01, 0x01, 0x00, 0x00, 0x00,	/* reg 0x35..0x3c */
	0x00, 0xFF, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00,	/* reg 0x3d..0x44 */
	0x00, 0x20, 0x0B, 0x00, 0x00, 0x02, 0x0A, 0x21,	/* reg 0x45..0x4c */
	0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x00, 0xC8,	/* reg 0x4d..0x54 */
	0x00, 0x00, 0x38, 0xFF, 0x01, 0x00, 0x08, 0x00,	/* reg 0x55..0x5c */
	0x00, 0x01, 0xCC, 0x0F, 0x01, 0xF1, 0x0D, 0x01,	/* reg 0x5d..0x64 */
	0x68, 0x00, 0x80, 0x08, 0xB8, 0x00, 0x00, 0x00,	/* reg 0x65..0x6c */
	0x00, 0x0F, 0x89, 0x00, 0x00, 0x00, 0x00, 0x00,	/* reg 0x6d..0x74 */
	0x00, 0x00, 0x01, 0x0F, 0x0D, 0x0E, 0x0E, 0x00,	/* reg 0x75..0x7c */
	0x00, 0x02, 0xC7, 0xFF, 0x9B, 0x00, 0x00, 0x00,	/* reg 0x7d..0x84 */
	0x01, 0x00, 0x00,				/* reg 0x85..0x87 */
};

static int vl53l1x_chip_init(struct vl53l1x_data *data)
{
	struct device *dev = regmap_get_device(data->regmap);
	unsigned int val;
	u16 model_id;
	int ret;

	if (!data->xshut_reset) {
		ret = regmap_write(data->regmap, VL53L1X_REG_SOFT_RESET, 0x00);
		if (ret)
			return ret;
		fsleep(100); /* conservative reset pulse, no spec */

		ret = regmap_write(data->regmap, VL53L1X_REG_SOFT_RESET, 0x01);
		if (ret)
			return ret;
		fsleep(1000); /* conservative boot wait, no spec */
	}

	ret = regmap_read_poll_timeout(data->regmap,
				       VL53L1X_REG_FIRMWARE__SYSTEM_STATUS, val,
				       val & BIT(0),
				       1 * USEC_PER_MSEC,
				       100 * USEC_PER_MSEC);
	if (ret)
		return dev_err_probe(dev, ret, "firmware boot timeout\n");

	ret = vl53l1x_read_u16(data, VL53L1X_REG_IDENTIFICATION__MODEL_ID,
			       &model_id);
	if (ret)
		return ret;

	if (model_id != VL53L1X_MODEL_ID_VAL)
		dev_info(dev, "unknown model id: 0x%04x, continuing\n", model_id);

	ret = regmap_bulk_write(data->regmap, VL53L1X_REG_DEFAULT_CONFIG,
				vl53l1x_default_config,
				sizeof(vl53l1x_default_config));
	if (ret)
		return ret;

	ret = regmap_read(data->regmap, VL53L1X_REG_GPIO_HV_MUX__CTRL, &val);
	if (ret)
		return ret;
	data->gpio_polarity = !!(val & VL53L1X_GPIO_HV_MUX_POLARITY);

	/* Initial ranging cycle for VHV calibration */
	ret = vl53l1x_start_ranging(data);
	if (ret)
		return ret;

	/* 1ms poll, 1s timeout covers max timing budgets (per ST Ultra Lite Driver) */
	ret = regmap_read_poll_timeout(data->regmap,
				       VL53L1X_REG_GPIO__TIO_HV_STATUS, val,
				       (val & 1) != data->gpio_polarity,
				       1 * USEC_PER_MSEC,
				       1000 * USEC_PER_MSEC);
	if (ret)
		return ret;

	ret = vl53l1x_clear_irq(data);
	if (ret)
		return ret;

	ret = vl53l1x_stop_ranging(data);
	if (ret)
		return ret;

	ret = regmap_write(data->regmap,
			   VL53L1X_REG_VHV_CONFIG__TIMEOUT_MACROP_LOOP_BOUND,
			   VL53L1X_VHV_LOOP_BOUND_TWO);
	if (ret)
		return ret;

	return regmap_write(data->regmap, VL53L1X_REG_VHV_CONFIG__INIT, 0x00);
}

static const struct reg_sequence vl53l1x_mode_short[] = {
	{ VL53L1X_REG_PHASECAL_CONFIG__TIMEOUT_MACROP,		0x14 },
	{ VL53L1X_REG_RANGE_CONFIG__VCSEL_PERIOD_A,		0x07 },
	{ VL53L1X_REG_RANGE_CONFIG__VCSEL_PERIOD_B,		0x05 },
	{ VL53L1X_REG_RANGE_CONFIG__VALID_PHASE_HIGH,		0x38 },
	{ VL53L1X_REG_SD_CONFIG__WOI_SD0,			0x07 },
	{ VL53L1X_REG_SD_CONFIG__WOI_SD1,			0x05 },
	{ VL53L1X_REG_SD_CONFIG__INITIAL_PHASE_SD0,		0x06 },
	{ VL53L1X_REG_SD_CONFIG__INITIAL_PHASE_SD1,		0x06 },
};

static const struct reg_sequence vl53l1x_mode_long[] = {
	{ VL53L1X_REG_PHASECAL_CONFIG__TIMEOUT_MACROP,		0x0A },
	{ VL53L1X_REG_RANGE_CONFIG__VCSEL_PERIOD_A,		0x0F },
	{ VL53L1X_REG_RANGE_CONFIG__VCSEL_PERIOD_B,		0x0D },
	{ VL53L1X_REG_RANGE_CONFIG__VALID_PHASE_HIGH,		0xB8 },
	{ VL53L1X_REG_SD_CONFIG__WOI_SD0,			0x0F },
	{ VL53L1X_REG_SD_CONFIG__WOI_SD1,			0x0D },
	{ VL53L1X_REG_SD_CONFIG__INITIAL_PHASE_SD0,		0x0E },
	{ VL53L1X_REG_SD_CONFIG__INITIAL_PHASE_SD1,		0x0E },
};

static const struct {
	const struct reg_sequence *regs;
	size_t num_regs;
} vl53l1x_mode_configs[] = {
	[VL53L1X_SHORT] = { vl53l1x_mode_short, ARRAY_SIZE(vl53l1x_mode_short) },
	[VL53L1X_LONG]  = { vl53l1x_mode_long, ARRAY_SIZE(vl53l1x_mode_long) },
};

static int vl53l1x_set_distance_mode(struct vl53l1x_data *data,
				     enum vl53l1x_distance_mode mode)
{
	int ret;

	if (mode >= ARRAY_SIZE(vl53l1x_mode_configs))
		return -EINVAL;

	ret = regmap_multi_reg_write(data->regmap,
				     vl53l1x_mode_configs[mode].regs,
				     vl53l1x_mode_configs[mode].num_regs);
	if (ret)
		return ret;

	data->distance_mode = mode;
	return 0;
}

/*
 * The timing budget controls how long the sensor spends collecting
 * a single range measurement. Pre-computed TIMEOUT_MACROP register
 * values from ST's VL53L1X Ultra Lite Driver.
 */
static int vl53l1x_set_timing_budget(struct vl53l1x_data *data, u16 budget_ms)
{
	u16 timeout_a, timeout_b;
	int ret;

	switch (data->distance_mode) {
	case VL53L1X_SHORT:
		switch (budget_ms) {
		case 15:
			timeout_a = 0x001D;
			timeout_b = 0x0027;
			break;
		case 20:
			timeout_a = 0x0051;
			timeout_b = 0x006E;
			break;
		case 33:
			timeout_a = 0x00D6;
			timeout_b = 0x006E;
			break;
		case 50:
			timeout_a = 0x01AE;
			timeout_b = 0x01E8;
			break;
		case 100:
			timeout_a = 0x02E1;
			timeout_b = 0x0388;
			break;
		case 200:
			timeout_a = 0x03E1;
			timeout_b = 0x0496;
			break;
		case 500:
			timeout_a = 0x0591;
			timeout_b = 0x05C1;
			break;
		default:
			return -EINVAL;
		}
		break;
	case VL53L1X_LONG:
		switch (budget_ms) {
		case 20:
			timeout_a = 0x001E;
			timeout_b = 0x0022;
			break;
		case 33:
			timeout_a = 0x0060;
			timeout_b = 0x006E;
			break;
		case 50:
			timeout_a = 0x00AD;
			timeout_b = 0x00C6;
			break;
		case 100:
			timeout_a = 0x01CC;
			timeout_b = 0x01EA;
			break;
		case 200:
			timeout_a = 0x02D9;
			timeout_b = 0x02F8;
			break;
		case 500:
			timeout_a = 0x048F;
			timeout_b = 0x04A4;
			break;
		default:
			return -EINVAL;
		}
		break;
	default:
		return -EINVAL;
	}

	ret = vl53l1x_write_u16(data, VL53L1X_REG_RANGE_CONFIG__TIMEOUT_MACROP_A,
				timeout_a);
	if (ret)
		return ret;

	return vl53l1x_write_u16(data, VL53L1X_REG_RANGE_CONFIG__TIMEOUT_MACROP_B,
				 timeout_b);
}

static int vl53l1x_set_inter_measurement_ms(struct vl53l1x_data *data,
					    u16 period_ms)
{
	u16 osc_calibrate_val;
	u16 clock_pll;
	u32 inter_meas;
	int ret;

	ret = vl53l1x_read_u16(data, VL53L1X_REG_RESULT__OSC_CALIBRATE_VAL,
			       &osc_calibrate_val);
	if (ret)
		return ret;

	clock_pll = osc_calibrate_val & VL53L1X_OSC_CALIBRATE_MASK;
	inter_meas = (clock_pll * period_ms * vl53l1x_osc_correction.numerator) /
		     vl53l1x_osc_correction.denominator;

	return vl53l1x_write_u32(data,
				 VL53L1X_REG_SYSTEM__INTERMEASUREMENT_PERIOD,
				 inter_meas);
}

static int vl53l1x_read_proximity(struct vl53l1x_data *data, int *val)
{
	unsigned int range_status;
	u16 distance;
	int ret;

	if (data->irq) {
		reinit_completion(&data->completion);

		ret = vl53l1x_clear_irq(data);
		if (ret)
			return ret;

		if (!wait_for_completion_timeout(&data->completion, HZ))
			return -ETIMEDOUT;
	} else {
		unsigned int rdy;

		/* 1ms poll, 1s timeout covers max timing budgets (per ST Ultra Lite Driver) */
		ret = regmap_read_poll_timeout(data->regmap,
					       VL53L1X_REG_GPIO__TIO_HV_STATUS, rdy,
					       (rdy & 1) != data->gpio_polarity,
					       1 * USEC_PER_MSEC,
					       1000 * USEC_PER_MSEC);
		if (ret)
			return ret;
	}

	ret = regmap_read(data->regmap, VL53L1X_REG_RESULT__RANGE_STATUS,
			  &range_status);
	if (ret)
		goto clear_irq;

	if (FIELD_GET(VL53L1X_RANGE_STATUS_MASK, range_status) !=
	    VL53L1X_RANGE_STATUS_VALID) {
		ret = -EIO;
		goto clear_irq;
	}

	ret = vl53l1x_read_u16(data,
			       VL53L1X_REG_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0,
			       &distance);
	if (ret)
		goto clear_irq;

	*val = distance;

clear_irq:
	vl53l1x_clear_irq(data);
	return ret;
}

static const struct iio_chan_spec vl53l1x_channels[] = {
	{
		.type = IIO_DISTANCE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				      BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 0,
		.scan_type = {
			.sign = 'u',
			.realbits = 16,
			.storagebits = 16,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static int vl53l1x_read_raw(struct iio_dev *indio_dev,
			    const struct iio_chan_spec *chan,
			    int *val, int *val2, long mask)
{
	struct vl53l1x_data *data = iio_priv(indio_dev);
	int ret;

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

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (!iio_device_claim_direct(indio_dev))
			return -EBUSY;
		ret = vl53l1x_read_proximity(data, val);
		iio_device_release_direct(indio_dev);
		if (ret)
			return ret;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = 0;
		*val2 = 1000;
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static const struct iio_info vl53l1x_info = {
	.read_raw = vl53l1x_read_raw,
	.validate_trigger = iio_validate_own_trigger,
};

static irqreturn_t vl53l1x_trigger_handler(int irq, void *priv)
{
	struct iio_poll_func *pf = priv;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct vl53l1x_data *data = iio_priv(indio_dev);
	struct {
		u16 distance;
		aligned_s64 timestamp;
	} scan = { };
	unsigned int range_status;
	int ret;

	ret = regmap_read(data->regmap, VL53L1X_REG_RESULT__RANGE_STATUS,
			  &range_status);
	if (ret)
		goto notify_and_clear_irq;
	if (FIELD_GET(VL53L1X_RANGE_STATUS_MASK, range_status) !=
		      VL53L1X_RANGE_STATUS_VALID)
		goto notify_and_clear_irq;

	ret = vl53l1x_read_u16(data,
			       VL53L1X_REG_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0,
			       &scan.distance);
	if (ret)
		goto notify_and_clear_irq;

	iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
				    iio_get_time_ns(indio_dev));

notify_and_clear_irq:
	iio_trigger_notify_done(indio_dev->trig);
	vl53l1x_clear_irq(data);

	return IRQ_HANDLED;
}

static irqreturn_t vl53l1x_irq_handler(int irq, void *priv)
{
	struct iio_dev *indio_dev = priv;
	struct vl53l1x_data *data = iio_priv(indio_dev);

	if (iio_buffer_enabled(indio_dev))
		iio_trigger_poll(indio_dev->trig);
	else
		complete(&data->completion);

	return IRQ_HANDLED;
}

static const struct iio_trigger_ops vl53l1x_trigger_ops = {
	.validate_device = iio_trigger_validate_own_device,
};

static void vl53l1x_stop_ranging_action(void *priv)
{
	vl53l1x_stop_ranging(priv);
}

static int vl53l1x_configure_irq(struct device *dev, int irq,
				 struct iio_dev *indio_dev)
{
	struct vl53l1x_data *data = iio_priv(indio_dev);
	int ret;

	ret = devm_request_irq(dev, irq, vl53l1x_irq_handler, IRQF_NO_THREAD,
			       indio_dev->name, indio_dev);
	if (ret)
		return ret;

	ret = regmap_write(data->regmap, VL53L1X_REG_SYSTEM__INTERRUPT_CONFIG_GPIO,
			   VL53L1X_INT_NEW_SAMPLE_READY);
	if (ret)
		return dev_err_probe(dev, ret, "failed to configure IRQ\n");

	return 0;
}

static int vl53l1x_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct vl53l1x_data *data;
	struct iio_dev *indio_dev;
	int ret;

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

	data = iio_priv(indio_dev);
	data->irq = client->irq;

	data->regmap = devm_regmap_init_i2c(client, &vl53l1x_regmap_config);
	if (IS_ERR(data->regmap))
		return dev_err_probe(dev, PTR_ERR(data->regmap),
				     "regmap initialization failed\n");

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

	/*
	 * XSHUT held low puts the chip in hardware standby. All register
	 * state is lost on de-assert so this is functionally a reset.
	 */
	data->xshut_reset = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
	if (IS_ERR(data->xshut_reset))
		return dev_err_probe(dev, PTR_ERR(data->xshut_reset),
				     "Cannot get reset control\n");

	/*
	 * 1.2 ms max boot duration.
	 * Datasheet Section 3.6 "Power up and boot sequence".
	 */
	fsleep(1200);

	ret = vl53l1x_chip_init(data);
	if (ret)
		return ret;

	ret = vl53l1x_set_distance_mode(data, VL53L1X_LONG);
	if (ret)
		return ret;

	/* 50 ms timing budget (per ST Ultra Lite Driver) */
	ret = vl53l1x_set_timing_budget(data, 50);
	if (ret)
		return ret;

	/* 50 ms inter-measurement period (per ST Ultra Lite Driver) */
	ret = vl53l1x_set_inter_measurement_ms(data, 50);
	if (ret)
		return ret;

	/*
	 * The hardware only supports "autonomous" continuous ranging mode.
	 * Start ranging here and leave it running for the lifetime of
	 * the device. Both direct reads and the buffer path rely on this.
	 */
	ret = vl53l1x_start_ranging(data);
	if (ret)
		return ret;

	ret = devm_add_action_or_reset(dev, vl53l1x_stop_ranging_action, data);
	if (ret)
		return ret;

	indio_dev->name = "vl53l1x";
	indio_dev->info = &vl53l1x_info;
	indio_dev->channels = vl53l1x_channels;
	indio_dev->num_channels = ARRAY_SIZE(vl53l1x_channels);
	indio_dev->modes = INDIO_DIRECT_MODE;

	if (client->irq) {
		struct iio_trigger *trig;

		init_completion(&data->completion);

		trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
					      iio_device_id(indio_dev));
		if (!trig)
			return -ENOMEM;

		trig->ops = &vl53l1x_trigger_ops;
		iio_trigger_set_drvdata(trig, indio_dev);
		ret = devm_iio_trigger_register(dev, trig);
		if (ret)
			return ret;

		indio_dev->trig = iio_trigger_get(trig);

		ret = vl53l1x_configure_irq(dev, client->irq, indio_dev);
		if (ret)
			return ret;

		ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
						      &vl53l1x_trigger_handler,
						      NULL);
		if (ret)
			return ret;
	}

	return devm_iio_device_register(dev, indio_dev);
}

static const struct i2c_device_id vl53l1x_id[] = {
	{ "vl53l1x" },
	{ }
};
MODULE_DEVICE_TABLE(i2c, vl53l1x_id);

static const struct of_device_id st_vl53l1x_dt_match[] = {
	{ .compatible = "st,vl53l1x" },
	{ }
};
MODULE_DEVICE_TABLE(of, st_vl53l1x_dt_match);

static struct i2c_driver vl53l1x_driver = {
	.driver = {
		.name = "vl53l1x-i2c",
		.of_match_table = st_vl53l1x_dt_match,
	},
	.probe = vl53l1x_probe,
	.id_table = vl53l1x_id,
};
module_i2c_driver(vl53l1x_driver);

MODULE_AUTHOR("Siratul Islam <email@sirat.me>");
MODULE_DESCRIPTION("ST VL53L1X ToF ranging sensor driver");
MODULE_LICENSE("Dual BSD/GPL");