Add support for the STMicroelectronics VL53L1X Time-of-Flight
ranging sensor with I2C interface.

Signed-off-by: Siratul Islam <email@sirat.me>
---
 MAINTAINERS                         |   1 +
 drivers/iio/proximity/Kconfig       |  14 +
 drivers/iio/proximity/Makefile      |   1 +
 drivers/iio/proximity/vl53l1x-i2c.c | 782 ++++++++++++++++++++++++++++
 4 files changed, 798 insertions(+)
 create mode 100644 drivers/iio/proximity/vl53l1x-i2c.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a142a97be4cb..50531a87bf2e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25098,6 +25098,7 @@ M:	Siratul Islam <email@sirat.me>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/iio/proximity/st,vl53l0x.yaml
+F:	drivers/iio/proximity/vl53l1x-i2c.c
 
 STABLE BRANCH
 M:	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
index 6070974c2c85..3b0fdeb03ecd 100644
--- a/drivers/iio/proximity/Kconfig
+++ b/drivers/iio/proximity/Kconfig
@@ -244,6 +244,20 @@ config VL53L0X_I2C
 	  To compile this driver as a module, choose M here: the
 	  module will be called vl53l0x-i2c.
 
+config VL53L1X_I2C
+	tristate "STMicroelectronics VL53L1X ToF ranger sensor (I2C)"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP_I2C
+	help
+	  Say Y here to build a driver for STMicroelectronics VL53L1X
+	  ToF ranger sensors with i2c interface.
+	  This driver can be used to measure the distance of objects.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called vl53l1x-i2c.
+
 config AW96103
 	tristate "AW96103/AW96105 Awinic proximity sensor"
 	select REGMAP_I2C
diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
index 152034d38c49..4352833dd8a4 100644
--- a/drivers/iio/proximity/Makefile
+++ b/drivers/iio/proximity/Makefile
@@ -23,5 +23,6 @@ obj-$(CONFIG_SX_COMMON) 	+= sx_common.o
 obj-$(CONFIG_SX9500)		+= sx9500.o
 obj-$(CONFIG_VCNL3020)		+= vcnl3020.o
 obj-$(CONFIG_VL53L0X_I2C)	+= vl53l0x-i2c.o
+obj-$(CONFIG_VL53L1X_I2C)	+= vl53l1x-i2c.o
 obj-$(CONFIG_AW96103)		+= aw96103.o
 
diff --git a/drivers/iio/proximity/vl53l1x-i2c.c b/drivers/iio/proximity/vl53l1x-i2c.c
new file mode 100644
index 000000000000..e6c3efeb6051
--- /dev/null
+++ b/drivers/iio/proximity/vl53l1x-i2c.c
@@ -0,0 +1,782 @@
+// 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/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/types.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_SOFT_RESET					0x0000
+#define VL53L1X_VHV_CONFIG__TIMEOUT_MACROP_LOOP_BOUND		0x0008
+#define VL53L1X_VHV_CONFIG__INIT				0x000B
+#define VL53L1X_GPIO_HV_MUX__CTRL				0x0030
+#define VL53L1X_GPIO__TIO_HV_STATUS				0x0031
+#define VL53L1X_SYSTEM__INTERRUPT_CONFIG_GPIO			0x0046
+#define VL53L1X_PHASECAL_CONFIG__TIMEOUT_MACROP			0x004B
+#define VL53L1X_RANGE_CONFIG__TIMEOUT_MACROP_A			0x005E
+#define VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_A			0x0060
+#define VL53L1X_RANGE_CONFIG__TIMEOUT_MACROP_B			0x0061
+#define VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_B			0x0063
+#define VL53L1X_RANGE_CONFIG__VALID_PHASE_HIGH			0x0069
+#define VL53L1X_SYSTEM__INTERMEASUREMENT_PERIOD			0x006C
+#define VL53L1X_SD_CONFIG__WOI_SD0				0x0078
+#define VL53L1X_SD_CONFIG__WOI_SD1				0x0079
+#define VL53L1X_SD_CONFIG__INITIAL_PHASE_SD0			0x007A
+#define VL53L1X_SD_CONFIG__INITIAL_PHASE_SD1			0x007B
+#define VL53L1X_SYSTEM__INTERRUPT_CLEAR				0x0086
+#define VL53L1X_SYSTEM__MODE_START				0x0087
+#define VL53L1X_RESULT__RANGE_STATUS				0x0089
+#define VL53L1X_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0	0x0096
+#define VL53L1X_RESULT__OSC_CALIBRATE_VAL			0x00DE
+#define VL53L1X_FIRMWARE__SYSTEM_STATUS				0x00E5
+#define VL53L1X_IDENTIFICATION__MODEL_ID			0x010F
+
+#define VL53L1X_MODEL_ID_VAL		0xEACC
+
+#define VL53L1X_DEFAULT_CONFIG_ADDR	0x2D
+
+#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
+
+/* Inter-measurement period uses PLL divider with 1.075 oscillator correction */
+#define VL53L1X_OSC_CALIBRATE_MASK	GENMASK(9, 0)
+#define VL53L1X_OSC_CORRECTION_FACTOR	1075
+#define VL53L1X_OSC_CORRECTION_DIVISOR	1000
+
+enum vl53l1x_distance_mode {
+	VL53L1X_SHORT,
+	VL53L1X_LONG,
+};
+
+struct vl53l1x_data {
+	struct regmap *regmap;
+	struct completion completion;
+	struct regulator *vdd_supply;
+	struct gpio_desc *xshut_gpio;
+	enum vl53l1x_distance_mode distance_mode;
+	u16 osc_calibrate_val;
+	u8 gpio_polarity;
+	int irq;
+};
+
+static const struct regmap_config vl53l1x_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+};
+
+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, 2);
+	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, 2);
+}
+
+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, 4);
+}
+
+static int vl53l1x_clear_irq(struct vl53l1x_data *data)
+{
+	return regmap_write(data->regmap, VL53L1X_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_SYSTEM__MODE_START,
+			    VL53L1X_MODE_START_TIMED);
+}
+
+static int vl53l1x_stop_ranging(struct vl53l1x_data *data)
+{
+	return regmap_write(data->regmap, VL53L1X_SYSTEM__MODE_START,
+			    VL53L1X_MODE_START_STOP);
+}
+
+/*
+ * Default configuration blob from ST's VL53L1X ULD (STSW-IMG009).
+ */
+static const u8 vl53l1x_default_config[] = {
+	/* 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34 */
+	0x00, 0x00, 0x00, 0x01, 0x02, 0x00, 0x02, 0x08,
+	/* 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C */
+	0x00, 0x08, 0x10, 0x01, 0x01, 0x00, 0x00, 0x00,
+	/* 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44 */
+	0x00, 0xFF, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00,
+	/* 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C */
+	0x00, 0x20, 0x0B, 0x00, 0x00, 0x02, 0x0A, 0x21,
+	/* 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54 */
+	0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x00, 0xC8,
+	/* 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C */
+	0x00, 0x00, 0x38, 0xFF, 0x01, 0x00, 0x08, 0x00,
+	/* 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64 */
+	0x00, 0x01, 0xCC, 0x0F, 0x01, 0xF1, 0x0D, 0x01,
+	/* 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C */
+	0x68, 0x00, 0x80, 0x08, 0xB8, 0x00, 0x00, 0x00,
+	/* 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74 */
+	0x00, 0x0F, 0x89, 0x00, 0x00, 0x00, 0x00, 0x00,
+	/* 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C */
+	0x00, 0x00, 0x01, 0x0F, 0x0D, 0x0E, 0x0E, 0x00,
+	/* 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84 */
+	0x00, 0x02, 0xC7, 0xFF, 0x9B, 0x00, 0x00, 0x00,
+	/* 0x85, 0x86, 0x87 */
+	0x01, 0x00, 0x00,
+};
+
+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_gpio) {
+		ret = regmap_write(data->regmap, VL53L1X_SOFT_RESET, 0x00);
+		if (ret)
+			return ret;
+		fsleep(100); /* conservative reset pulse, no spec */
+
+		ret = regmap_write(data->regmap, VL53L1X_SOFT_RESET, 0x01);
+		if (ret)
+			return ret;
+		fsleep(1000); /* conservative boot wait, no spec */
+	}
+
+	ret = regmap_read_poll_timeout(data->regmap,
+				       VL53L1X_FIRMWARE__SYSTEM_STATUS, val,
+				       val & BIT(0),
+				       1 * USEC_PER_MSEC,
+				       100 * USEC_PER_MSEC);
+	if (ret) {
+		dev_err(dev, "firmware boot timeout\n");
+		return ret;
+	}
+
+	ret = vl53l1x_read_u16(data, VL53L1X_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 = vl53l1x_read_u16(data, VL53L1X_RESULT__OSC_CALIBRATE_VAL,
+			       &data->osc_calibrate_val);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_write(data->regmap, VL53L1X_DEFAULT_CONFIG_ADDR,
+				vl53l1x_default_config,
+				sizeof(vl53l1x_default_config));
+	if (ret)
+		return ret;
+
+	ret = regmap_read(data->regmap, VL53L1X_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 ULD) */
+	ret = regmap_read_poll_timeout(data->regmap,
+				       VL53L1X_GPIO__TIO_HV_STATUS, val,
+				       (val & 0x01) == (!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_VHV_CONFIG__TIMEOUT_MACROP_LOOP_BOUND,
+			   VL53L1X_VHV_LOOP_BOUND_TWO);
+	if (ret)
+		return ret;
+
+	return regmap_write(data->regmap, VL53L1X_VHV_CONFIG__INIT, 0x00);
+}
+
+static const struct reg_sequence vl53l1x_mode_short[] = {
+	{ VL53L1X_PHASECAL_CONFIG__TIMEOUT_MACROP,	0x14 },
+	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_A,		0x07 },
+	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_B,		0x05 },
+	{ VL53L1X_RANGE_CONFIG__VALID_PHASE_HIGH,	0x38 },
+	{ VL53L1X_SD_CONFIG__WOI_SD0,			0x07 },
+	{ VL53L1X_SD_CONFIG__WOI_SD1,			0x05 },
+	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD0,		6 },
+	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD1,		6 },
+};
+
+static const struct reg_sequence vl53l1x_mode_long[] = {
+	{ VL53L1X_PHASECAL_CONFIG__TIMEOUT_MACROP,	0x0A },
+	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_A,		0x0F },
+	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_B,		0x0D },
+	{ VL53L1X_RANGE_CONFIG__VALID_PHASE_HIGH,	0xB8 },
+	{ VL53L1X_SD_CONFIG__WOI_SD0,			0x0F },
+	{ VL53L1X_SD_CONFIG__WOI_SD1,			0x0D },
+	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD0,		14 },
+	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD1,		14 },
+};
+
+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 ULD.
+ */
+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_RANGE_CONFIG__TIMEOUT_MACROP_A,
+				timeout_a);
+	if (ret)
+		return ret;
+
+	return vl53l1x_write_u16(data, VL53L1X_RANGE_CONFIG__TIMEOUT_MACROP_B,
+				 timeout_b);
+}
+
+static int vl53l1x_set_inter_measurement_ms(struct vl53l1x_data *data,
+					    u16 period_ms)
+{
+	u16 clock_pll = data->osc_calibrate_val & VL53L1X_OSC_CALIBRATE_MASK;
+	u32 inter_meas;
+
+	inter_meas = clock_pll * period_ms;
+	inter_meas = (inter_meas * VL53L1X_OSC_CORRECTION_FACTOR) /
+		     VL53L1X_OSC_CORRECTION_DIVISOR;
+
+	return vl53l1x_write_u32(data, VL53L1X_SYSTEM__INTERMEASUREMENT_PERIOD,
+				 inter_meas);
+}
+
+static int vl53l1x_read_proximity(struct vl53l1x_data *data, int *val)
+{
+	unsigned long time_left;
+	unsigned int range_status;
+	u16 distance;
+	int ret;
+
+	if (data->irq) {
+		reinit_completion(&data->completion);
+
+		ret = vl53l1x_clear_irq(data);
+		if (ret)
+			return ret;
+
+		time_left = wait_for_completion_timeout(&data->completion, HZ);
+		if (time_left == 0)
+			return -ETIMEDOUT;
+	} else {
+		unsigned int rdy;
+
+		/* 1ms poll, 1s timeout covers max timing budgets (per ST ULD) */
+		ret = regmap_read_poll_timeout(data->regmap,
+					       VL53L1X_GPIO__TIO_HV_STATUS, rdy,
+					       (rdy & 0x01) == (!data->gpio_polarity),
+					       1 * USEC_PER_MSEC,
+					       1000 * USEC_PER_MSEC);
+		if (ret)
+			return ret;
+	}
+
+	ret = regmap_read(data->regmap, VL53L1X_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_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_RESULT__RANGE_STATUS,
+			  &range_status);
+	if (ret || FIELD_GET(VL53L1X_RANGE_STATUS_MASK, range_status) !=
+			   VL53L1X_RANGE_STATUS_VALID)
+		goto notify_and_clear_irq;
+
+	ret = vl53l1x_read_u16(data,
+			       VL53L1X_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0,
+			       &scan.distance);
+	if (ret)
+		goto notify_and_clear_irq;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &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 int vl53l1x_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct vl53l1x_data *data = iio_priv(indio_dev);
+
+	return vl53l1x_start_ranging(data);
+}
+
+static int vl53l1x_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct vl53l1x_data *data = iio_priv(indio_dev);
+	int ret;
+
+	ret = vl53l1x_stop_ranging(data);
+	if (ret)
+		return ret;
+
+	reinit_completion(&data->completion);
+	wait_for_completion_timeout(&data->completion, HZ / 10);
+
+	return vl53l1x_clear_irq(data);
+}
+
+static const struct iio_buffer_setup_ops vl53l1x_buffer_setup_ops = {
+	.postenable = &vl53l1x_buffer_postenable,
+	.predisable = &vl53l1x_buffer_predisable,
+};
+
+static const struct iio_trigger_ops vl53l1x_trigger_ops = {
+	.validate_device = iio_trigger_validate_own_device,
+};
+
+static void vl53l1x_stop_ranging_action(void *_data)
+{
+	vl53l1x_stop_ranging(_data);
+}
+
+static void vl53l1x_power_off(void *_data)
+{
+	struct vl53l1x_data *data = _data;
+
+	gpiod_set_value_cansleep(data->xshut_gpio, 1);
+	regulator_disable(data->vdd_supply);
+}
+
+static int vl53l1x_power_on(struct vl53l1x_data *data)
+{
+	int ret;
+
+	ret = regulator_enable(data->vdd_supply);
+	if (ret)
+		return ret;
+
+	gpiod_set_value_cansleep(data->xshut_gpio, 0);
+	/*
+	 * 1.2 ms max boot duration.
+	 * Datasheet Section 3.6 "Power up and boot sequence".
+	 */
+	fsleep(1200);
+
+	return 0;
+}
+
+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 dev_err_probe(dev, ret, "failed to request IRQ\n");
+
+	ret = regmap_write(data->regmap, VL53L1X_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;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_I2C_BLOCK |
+				     I2C_FUNC_SMBUS_BYTE_DATA))
+		return -EOPNOTSUPP;
+
+	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");
+
+	data->vdd_supply = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(data->vdd_supply))
+		return dev_err_probe(dev, PTR_ERR(data->vdd_supply),
+				     "Unable to get VDD regulator\n");
+
+	data->xshut_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(data->xshut_gpio))
+		return dev_err_probe(dev, PTR_ERR(data->xshut_gpio),
+				     "Cannot get reset GPIO\n");
+
+	ret = vl53l1x_power_on(data);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to power on the chip\n");
+
+	ret = devm_add_action_or_reset(dev, vl53l1x_power_off, data);
+	if (ret)
+		return ret;
+
+	ret = vl53l1x_chip_init(data);
+	if (ret)
+		return ret;
+
+	ret = vl53l1x_set_distance_mode(data, VL53L1X_LONG);
+	if (ret)
+		return ret;
+
+	ret = vl53l1x_set_timing_budget(data, 50);
+	if (ret)
+		return ret;
+
+	ret = vl53l1x_set_inter_measurement_ms(data, 50);
+	if (ret)
+		return ret;
+
+	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,
+						      &vl53l1x_buffer_setup_ops);
+		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");
-- 
2.53.0

On Thu, Mar 12, 2026 at 04:40:37AM +0600, Siratul Islam wrote:
> Add support for the STMicroelectronics VL53L1X Time-of-Flight
> ranging sensor with I2C interface.

...

> +#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/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>

+ time.h // for USEC_PER_*

> +#include <linux/types.h>

+ asm/byteorder.h // for be16_to_*() et alai

...

> +#define VL53L1X_OSC_CORRECTION_FACTOR	1075
> +#define VL53L1X_OSC_CORRECTION_DIVISOR	1000

In math.h we have struct u32_fract. Use that instead

/* ...the comment... */
static const struct u32_fract ..._correction = {
	.numerator = 1075,
	.denominator = 1000,
};

...

> +struct vl53l1x_data {
> +	struct regmap *regmap;
> +	struct completion completion;
> +	struct regulator *vdd_supply;
> +	struct gpio_desc *xshut_gpio;
> +	enum vl53l1x_distance_mode distance_mode;
> +	u16 osc_calibrate_val;
> +	u8 gpio_polarity;
> +	int irq;
> +};

> +static const struct regmap_config vl53l1x_regmap_config = {
> +	.reg_bits = 16,
> +	.val_bits = 8,

No cache?

> +};

...

> +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, 2);

Here, and everywhere else in the same situation use sizeof().

> +	if (ret)
> +		return ret;
> +
> +	*val = be16_to_cpu(buf);
> +	return 0;
> +}

...

> +static int vl53l1x_clear_irq(struct vl53l1x_data *data)
> +{
> +	return regmap_write(data->regmap, VL53L1X_SYSTEM__INTERRUPT_CLEAR,
> +			    0x01);

It's perfectly one line (yes, it's fine to have it 81 characters).

> +}

...

> +static const u8 vl53l1x_default_config[] = {
> +	/* 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34 */

	Just compress this to


> +	0x00, 0x00, 0x00, 0x01, 0x02, 0x00, 0x02, 0x08,

	0x00, 0x00, 0x00, 0x01, 0x02, 0x00, 0x02, 0x08,		/* 0x2d..0x34 */

Same approach to the rest.

> +	/* 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C */
> +	0x00, 0x08, 0x10, 0x01, 0x01, 0x00, 0x00, 0x00,
> +	/* 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44 */
> +	0x00, 0xFF, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00,
> +	/* 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C */
> +	0x00, 0x20, 0x0B, 0x00, 0x00, 0x02, 0x0A, 0x21,
> +	/* 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54 */
> +	0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x00, 0xC8,
> +	/* 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C */
> +	0x00, 0x00, 0x38, 0xFF, 0x01, 0x00, 0x08, 0x00,
> +	/* 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64 */
> +	0x00, 0x01, 0xCC, 0x0F, 0x01, 0xF1, 0x0D, 0x01,
> +	/* 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C */
> +	0x68, 0x00, 0x80, 0x08, 0xB8, 0x00, 0x00, 0x00,
> +	/* 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74 */
> +	0x00, 0x0F, 0x89, 0x00, 0x00, 0x00, 0x00, 0x00,
> +	/* 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C */
> +	0x00, 0x00, 0x01, 0x0F, 0x0D, 0x0E, 0x0E, 0x00,
> +	/* 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84 */
> +	0x00, 0x02, 0xC7, 0xFF, 0x9B, 0x00, 0x00, 0x00,
> +	/* 0x85, 0x86, 0x87 */
> +	0x01, 0x00, 0x00,
> +};

...

> +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_gpio) {
> +		ret = regmap_write(data->regmap, VL53L1X_SOFT_RESET, 0x00);
> +		if (ret)
> +			return ret;
> +		fsleep(100); /* conservative reset pulse, no spec */
> +
> +		ret = regmap_write(data->regmap, VL53L1X_SOFT_RESET, 0x01);
> +		if (ret)
> +			return ret;
> +		fsleep(1000); /* conservative boot wait, no spec */
> +	}
> +
> +	ret = regmap_read_poll_timeout(data->regmap,
> +				       VL53L1X_FIRMWARE__SYSTEM_STATUS, val,
> +				       val & BIT(0),
> +				       1 * USEC_PER_MSEC,
> +				       100 * USEC_PER_MSEC);
> +	if (ret) {

> +		dev_err(dev, "firmware boot timeout\n");
> +		return ret;

This is used solely in probe phase, hence it's fine to

		return dev_err_probe(...);

> +	}
> +
> +	ret = vl53l1x_read_u16(data, VL53L1X_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 = vl53l1x_read_u16(data, VL53L1X_RESULT__OSC_CALIBRATE_VAL,
> +			       &data->osc_calibrate_val);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_bulk_write(data->regmap, VL53L1X_DEFAULT_CONFIG_ADDR,
> +				vl53l1x_default_config,
> +				sizeof(vl53l1x_default_config));
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(data->regmap, VL53L1X_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 ULD) */

What does ST ULD mean?! Please, avoid being cryptic in the comments.

> +	ret = regmap_read_poll_timeout(data->regmap,
> +				       VL53L1X_GPIO__TIO_HV_STATUS, val,
> +				       (val & 0x01) == (!data->gpio_polarity),

Too many parentheses

> +				       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_VHV_CONFIG__TIMEOUT_MACROP_LOOP_BOUND,
> +			   VL53L1X_VHV_LOOP_BOUND_TWO);
> +	if (ret)
> +		return ret;
> +
> +	return regmap_write(data->regmap, VL53L1X_VHV_CONFIG__INIT, 0x00);
> +}

...

> +static const struct reg_sequence vl53l1x_mode_short[] = {
> +	{ VL53L1X_PHASECAL_CONFIG__TIMEOUT_MACROP,	0x14 },
> +	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_A,		0x07 },
> +	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_B,		0x05 },
> +	{ VL53L1X_RANGE_CONFIG__VALID_PHASE_HIGH,	0x38 },
> +	{ VL53L1X_SD_CONFIG__WOI_SD0,			0x07 },
> +	{ VL53L1X_SD_CONFIG__WOI_SD1,			0x05 },

> +	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD0,		6 },
> +	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD1,		6 },

Why out of a sudden decimal values? Why the rest is not decimal?

> +};
> +
> +static const struct reg_sequence vl53l1x_mode_long[] = {
> +	{ VL53L1X_PHASECAL_CONFIG__TIMEOUT_MACROP,	0x0A },
> +	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_A,		0x0F },
> +	{ VL53L1X_RANGE_CONFIG__VCSEL_PERIOD_B,		0x0D },
> +	{ VL53L1X_RANGE_CONFIG__VALID_PHASE_HIGH,	0xB8 },
> +	{ VL53L1X_SD_CONFIG__WOI_SD0,			0x0F },
> +	{ VL53L1X_SD_CONFIG__WOI_SD1,			0x0D },
> +	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD0,		14 },
> +	{ VL53L1X_SD_CONFIG__INITIAL_PHASE_SD1,		14 },

Ditto.

> +};

...

> +	inter_meas = clock_pll * period_ms;
> +	inter_meas = (inter_meas * VL53L1X_OSC_CORRECTION_FACTOR) /
> +		     VL53L1X_OSC_CORRECTION_DIVISOR;

Will become

	inter_meas = (clock_pll * period_ms * ..._correction.numerator) / ..._correction.denominator.

...


> +static int vl53l1x_read_proximity(struct vl53l1x_data *data, int *val)
> +{
> +	unsigned long time_left;

Useless, one time use variable.

> +	unsigned int range_status;
> +	u16 distance;
> +	int ret;
> +
> +	if (data->irq) {
> +		reinit_completion(&data->completion);
> +
> +		ret = vl53l1x_clear_irq(data);
> +		if (ret)
> +			return ret;
> +
> +		time_left = wait_for_completion_timeout(&data->completion, HZ);
> +		if (time_left == 0)
> +			return -ETIMEDOUT;

		if (... == 0)
			return -ETIMEDOUT;

> +	} else {
> +		unsigned int rdy;
> +
> +		/* 1ms poll, 1s timeout covers max timing budgets (per ST ULD) */
> +		ret = regmap_read_poll_timeout(data->regmap,
> +					       VL53L1X_GPIO__TIO_HV_STATUS, rdy,
> +					       (rdy & 0x01) == (!data->gpio_polarity),

Too many parentheses.

> +					       1 * USEC_PER_MSEC,
> +					       1000 * USEC_PER_MSEC);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = regmap_read(data->regmap, VL53L1X_RESULT__RANGE_STATUS,
> +			  &range_status);
> +	if (ret)
> +		goto clear_irq;
> +
> +	if (FIELD_GET(VL53L1X_RANGE_STATUS_MASK, range_status) != VL53L1X_RANGE_STATUS_VALID) {

Be consistent in the chosen style. Either 80 (which is still preferable in IIO)
or 100, but everywhere.

> +		ret = -EIO;
> +		goto clear_irq;
> +	}
> +
> +	ret = vl53l1x_read_u16(data,
> +			       VL53L1X_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0,
> +			       &distance);
> +	if (ret)
> +		goto clear_irq;
> +
> +	*val = distance;
> +
> +clear_irq:
> +	vl53l1x_clear_irq(data);
> +	return ret;
> +}

...

> +static int vl53l1x_read_raw(struct iio_dev *indio_dev,
> +			    const struct iio_chan_spec *chan, int *val,
> +			    int *val2, long mask)

Try to make wraps on a logical borders:

static int vl53l1x_read_raw(struct iio_dev *indio_dev,
			    const struct iio_chan_spec *chan,
			    int *val, int *val2, long mask)

...

> +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_RESULT__RANGE_STATUS,
> +			  &range_status);
> +	if (ret || FIELD_GET(VL53L1X_RANGE_STATUS_MASK, range_status) !=
> +			   VL53L1X_RANGE_STATUS_VALID)

Just split for the sake of readability.

> +		goto notify_and_clear_irq;

	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_RESULT__FINAL_CROSSTALK_CORRECTED_RANGE_MM_SD0,
> +			       &scan.distance);
> +	if (ret)
> +		goto notify_and_clear_irq;
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, &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 int vl53l1x_buffer_predisable(struct iio_dev *indio_dev)
> +{
> +	struct vl53l1x_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = vl53l1x_stop_ranging(data);
> +	if (ret)
> +		return ret;
> +
> +	reinit_completion(&data->completion);

> +	wait_for_completion_timeout(&data->completion, HZ / 10);

No error condition check?

> +	return vl53l1x_clear_irq(data);
> +}

...

> +static int vl53l1x_power_on(struct vl53l1x_data *data)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(data->vdd_supply);
> +	if (ret)
> +		return ret;
> +
> +	gpiod_set_value_cansleep(data->xshut_gpio, 0);
> +	/*
> +	 * 1.2 ms max boot duration.
> +	 * Datasheet Section 3.6 "Power up and boot sequence".
> +	 */
> +	fsleep(1200);
> +
> +	return 0;
> +}

...

> +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);

There is more room on the previous lines, use it.

> +	if (ret)

> +		return dev_err_probe(dev, ret, "failed to request IRQ\n");

Dup. IRQ core prints this for you.

> +
> +	ret = regmap_write(data->regmap, VL53L1X_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;

> +	if (!i2c_check_functionality(client->adapter,
> +				     I2C_FUNC_SMBUS_READ_I2C_BLOCK |
> +				     I2C_FUNC_SMBUS_BYTE_DATA))
> +		return -EOPNOTSUPP;

Why not checking for this before even doing any allocations?

> +	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");
> +
> +	data->vdd_supply = devm_regulator_get(dev, "vdd");
> +	if (IS_ERR(data->vdd_supply))
> +		return dev_err_probe(dev, PTR_ERR(data->vdd_supply),
> +				     "Unable to get VDD regulator\n");

> +	data->xshut_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(data->xshut_gpio))
> +		return dev_err_probe(dev, PTR_ERR(data->xshut_gpio),
> +				     "Cannot get reset GPIO\n");

If it's a reset (semantically), use reset-gpio driver and reset APIs here.

> +	ret = vl53l1x_power_on(data);
> +	if (ret)

> +		return dev_err_probe(dev, ret,
> +				     "Failed to power on the chip\n");

Single line.

> +
> +	ret = devm_add_action_or_reset(dev, vl53l1x_power_off, data);
> +	if (ret)
> +		return ret;
> +
> +	ret = vl53l1x_chip_init(data);
> +	if (ret)
> +		return ret;
> +
> +	ret = vl53l1x_set_distance_mode(data, VL53L1X_LONG);
> +	if (ret)
> +		return ret;
> +
> +	ret = vl53l1x_set_timing_budget(data, 50);
> +	if (ret)
> +		return ret;
> +
> +	ret = vl53l1x_set_inter_measurement_ms(data, 50);
> +	if (ret)
> +		return ret;
> +
> +	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));

More room on the previous lines, use it.

> +		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,
> +						      &vl53l1x_buffer_setup_ops);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}

-- 
With Best Regards,
Andy Shevchenko

On Thu, Mar 12, 2026 at 8:58 PM Andy Shevchenko
<andriy.shevchenko@intel.com> wrote:
>
> On Thu, Mar 12, 2026 at 04:40:37AM +0600, Siratul Islam wrote:
> > Add support for the STMicroelectronics VL53L1X Time-of-Flight
> > ranging sensor with I2C interface.
> ...
>
> > +static const struct regmap_config vl53l1x_regmap_config = {
> > +     .reg_bits = 16,
> > +     .val_bits = 8,
>
> No cache?
>
The result registers change on every measurement, so caching doesn't
apply well here.
Will add .cache_type = REGCACHE_NONE  with a comment to clarify.
> > +};
>
> ...
> > +
> > +     reinit_completion(&data->completion);
>
> > +     wait_for_completion_timeout(&data->completion, HZ / 10);
>
> No error condition check?
>
This is only a short drain to make sure any pending IRQ has been
handled before we stop
the device and clear the interrupt line. A timeout here is not treated
as a failure and the device
is being shut down anyway, so I intentionally do not check the return value.
>
> ...
>
> > +     data->xshut_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> > +     if (IS_ERR(data->xshut_gpio))
> > +             return dev_err_probe(dev, PTR_ERR(data->xshut_gpio),
> > +                                  "Cannot get reset GPIO\n");
>
> If it's a reset (semantically), use reset-gpio driver and reset APIs here.
>
The XSHUT pin is a shutdown/enable pin rather than a true reset line,
and the existing shared st,vl53l0x.yaml
binding already defines it as reset-gpios. So I am keeping the GPIO
consumer API here.
>
>

Sending v4 with all other fixes from your review, shortly.

Thanks,
Sirat

On Thu, 12 Mar 2026 23:37:26 +0600
Sirat <email@sirat.me> wrote:

> On Thu, Mar 12, 2026 at 8:58 PM Andy Shevchenko
> <andriy.shevchenko@intel.com> wrote:
> >
> > On Thu, Mar 12, 2026 at 04:40:37AM +0600, Siratul Islam wrote:  
> > > Add support for the STMicroelectronics VL53L1X Time-of-Flight
> > > ranging sensor with I2C interface.  
> > ...
> >  
> > > +static const struct regmap_config vl53l1x_regmap_config = {
> > > +     .reg_bits = 16,
> > > +     .val_bits = 8,  
> >
> > No cache?
> >  
> The result registers change on every measurement, so caching doesn't
> apply well here.
> Will add .cache_type = REGCACHE_NONE  with a comment to clarify.

That's always the case, so more interesting is what registers
don't change? Can just mark the result registers as volatile
and get the advantages from caching the rest.

Someone else may have commented on it already, but please
slow down a bit on sending new versions.  Typically 1 a week
is a reasonable cadence unless things are very near to merge
and you are being asked for minor final tweaks in which case
one every few days is fine.

Jonathan



> > > +}; 

On Thu, Mar 12, 2026 at 11:37:26PM +0600, Sirat wrote:
> On Thu, Mar 12, 2026 at 8:58 PM Andy Shevchenko
> <andriy.shevchenko@intel.com> wrote:
> > On Thu, Mar 12, 2026 at 04:40:37AM +0600, Siratul Islam wrote:

...

> > > +static const struct regmap_config vl53l1x_regmap_config = {
> > > +     .reg_bits = 16,
> > > +     .val_bits = 8,
> >
> > No cache?
> >
> The result registers change on every measurement, so caching doesn't
> apply well here.
> Will add .cache_type = REGCACHE_NONE  with a comment to clarify.

OK!

> > > +};

...

> > > +     reinit_completion(&data->completion);
> >
> > > +     wait_for_completion_timeout(&data->completion, HZ / 10);
> >
> > No error condition check?
> >
> This is only a short drain to make sure any pending IRQ has been
> handled before we stop
> the device and clear the interrupt line. A timeout here is not treated
> as a failure and the device
> is being shut down anyway, so I intentionally do not check the return value.

Based on the above experience, you know how to improve this.

...

> > > +     data->xshut_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> > > +     if (IS_ERR(data->xshut_gpio))
> > > +             return dev_err_probe(dev, PTR_ERR(data->xshut_gpio),
> > > +                                  "Cannot get reset GPIO\n");
> >
> > If it's a reset (semantically), use reset-gpio driver and reset APIs here.
> >
> The XSHUT pin is a shutdown/enable pin rather than a true reset line,
> and the existing shared st,vl53l0x.yaml
> binding already defines it as reset-gpios. So I am keeping the GPIO
> consumer API here.

And? reset-gpio driver is exactly for those cases. Please, move your driver
code accordingly.

> Sending v4 with all other fixes from your review, shortly.

Please, take care of the comments first.

-- 
With Best Regards,
Andy Shevchenko

On Fri, Mar 13, 2026 at 3:35 PM Andy Shevchenko
<andriy.shevchenko@intel.com> wrote:
>
> On Thu, Mar 12, 2026 at 11:37:26PM +0600, Sirat wrote:
> > On Thu, Mar 12, 2026 at 8:58 PM Andy Shevchenko
> > <andriy.shevchenko@intel.com> wrote:
> > > On Thu, Mar 12, 2026 at 04:40:37AM +0600, Siratul Islam wrote:
>
> ...
> > >
> > > If it's a reset (semantically), use reset-gpio driver and reset APIs here.
> > >
> > The XSHUT pin is a shutdown/enable pin rather than a true reset line,
> > and the existing shared st,vl53l0x.yaml
> > binding already defines it as reset-gpios. So I am keeping the GPIO
> > consumer API here.
>
> And? reset-gpio driver is exactly for those cases. Please, move your driver
> code accordingly.
>
Blame is on me for not realizing that reset controller now also
supports "reset-gpios", my apologies.
My original hesitation was due to not willing to modify the binding to
add "resets"

I will switch to the reset controller.
>
>

Thanks,
Sirat