[PATCH 0/2] iio: light: Add ROHM BH1730FVC ambient light sensor driver

[PATCH 0/2] iio: light: Add ROHM BH1730FVC ambient light sensor driver

[Alexandre Hamamdjian via B4 Relay]

Add a driver and devicetree binding for the ROHM BH1730FVC ambient
light sensor. This sensor is found on the Nintendo Switch console,
where it is used by the system for automatic display brightness
adjustment.

Signed-off-by: Alexandre Hamamdjian <azkali.limited@gmail.com>
---
CTCaer (2):
      dt-bindings: iio: light: Add ROHM BH1730FVC binding
      iio: light: bh1730: Add bh1730 light sensor driver

 .../bindings/iio/light/rohm,bh1730fvc.yaml         |  95 +++
 drivers/iio/light/Kconfig                          |   9 +
 drivers/iio/light/Makefile                         |   1 +
 drivers/iio/light/bh1730.c                         | 686 +++++++++++++++++++++
 4 files changed, 791 insertions(+)
---
base-commit: e98d21c170b01ddef366f023bbfcf6b31509fa83
change-id: 20260511-bh1730-1e302acda4f8

Best regards,
--  
Alexandre Hamamdjian <azkali.limited@gmail.com>

[PATCH 1/2] dt-bindings: iio: light: Add ROHM BH1730FVC binding

[Alexandre Hamamdjian via B4 Relay]

From: CTCaer <ctcaer@gmail.com>

Add a YAML binding for the ROHM BH1730FVC ambient light sensor.
Documents the required compatible string, the als-vdd/als-vid
regulators, and the rohm,integration-cycle, rohm,lux-multiplier,
rohm,opt-win-coeff and rohm,gain-coeff calibration properties
consumed by the driver.

Signed-off-by: CTCaer <ctcaer@gmail.com>
Signed-off-by: Alexandre Hamamdjian <azkali.limited@gmail.com>
---
 .../bindings/iio/light/rohm,bh1730fvc.yaml         | 95 ++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/light/rohm,bh1730fvc.yaml b/Documentation/devicetree/bindings/iio/light/rohm,bh1730fvc.yaml
new file mode 100644
index 000000000000..6273b69e82ab
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/light/rohm,bh1730fvc.yaml
@@ -0,0 +1,95 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/light/rohm,bh1730fvc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ROHM BH1730FVC ambient light sensor
+
+maintainers:
+  - CTCaer <ctcaer@gmail.com>
+
+description:
+  Digital 16-bit ambient light sensor with an I2C interface. The device has
+  two photodiodes (visible and infrared) and supports four gain settings and
+  programmable integration time.
+
+properties:
+  compatible:
+    const: rohm,bh1730fvc
+
+  reg:
+    maxItems: 1
+
+  als-vdd-supply:
+    description: Regulator for the analog/digital supply (VDD).
+
+  als-vid-supply:
+    description: Regulator for the LED indicator supply (VID).
+
+  rohm,integration-cycle:
+    description:
+      Number of internal clock cycles used for the ADC integration time.
+      Used together with rohm,lux-multiplier to calibrate the lux output.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  rohm,lux-multiplier:
+    description:
+      Lux scaling multiplier applied after integration. Used together with
+      rohm,integration-cycle to calibrate the lux output.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  rohm,opt-win-coeff:
+    description:
+      Optical-window calibration coefficients. Specified as a flat list of
+      triplets <rc cv ci>, one triplet per window region, where rc is the
+      visible/IR ratio cutoff and cv/ci are the visible and IR weighting
+      factors used in that region.
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    items:
+      minItems: 3
+      maxItems: 3
+
+  rohm,gain-coeff:
+    description:
+      Per-gain sensitivity coefficients. Eight u32 values arranged as four
+      <cl fl> pairs, one pair for each supported gain (1x, 2x, 64x, 128x).
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 8
+    maxItems: 8
+
+required:
+  - compatible
+  - reg
+
+dependencies:
+  rohm,integration-cycle: ['rohm,lux-multiplier']
+  rohm,lux-multiplier: ['rohm,integration-cycle']
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        light-sensor@29 {
+            compatible = "rohm,bh1730fvc";
+            reg = <0x29>;
+            als-vdd-supply = <&vdd_als>;
+            als-vid-supply = <&vid_als>;
+            rohm,integration-cycle = <38>;
+            rohm,lux-multiplier = <1000>;
+            rohm,opt-win-coeff = <260 1290 2733>,
+                                 <550 795 859>,
+                                 <1090 510 345>,
+                                 <2130 276 130>;
+            rohm,gain-coeff = <3000 0xffffffff
+                               2000 9800
+                               15 60000
+                               0 1300>;
+        };
+    };
+
+...

-- 
2.54.0

[PATCH 2/2] iio: light: bh1730: Add bh1730 light sensor driver

[Alexandre Hamamdjian via B4 Relay]

From: CTCaer <ctcaer@gmail.com>

Add a driver for the ROHM BH1730FVC ambient light sensor. The device
is a 16-bit I2C digital sensor with separate visible and infrared
photodiodes, four selectable gains (1x/2x/64x/128x) and a programmable
integration time.

The driver exposes illuminance via IIO, performs runtime gain and
integration-time tracking to keep the ADC in range, and supports
optional als-vdd / als-vid regulators. Per-board lux calibration data
(integration cycles, lux multiplier, optical-window coefficients, and
gain sensitivity coefficients) can be supplied via device tree;
sensible defaults are used otherwise.

Signed-off-by: CTCaer <ctcaer@gmail.com>
Signed-off-by: Alexandre Hamamdjian <azkali.limited@gmail.com>
---
 drivers/iio/light/Kconfig  |   9 +
 drivers/iio/light/Makefile |   1 +
 drivers/iio/light/bh1730.c | 686 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 696 insertions(+)

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index eff33e456c70..3869060567dd 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -135,6 +135,15 @@ config AS73211
 	 This driver can also be built as a module.  If so, the module
 	 will be called as73211.
 
+config BH1730
+	tristate "ROHM BH1730 ambient light sensor"
+	depends on I2C
+	help
+	  Say Y here to build support for the ROHM BH1730 ambient light sensor.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called bh1730.
+
 config BH1745
 	tristate "ROHM BH1745 colour sensor"
 	depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index c0048e0d5ca8..27ef7906a02a 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_APDS9306)		+= apds9306.o
 obj-$(CONFIG_APDS9960)		+= apds9960.o
 obj-$(CONFIG_AS73211)		+= as73211.o
+obj-$(CONFIG_BH1730)		+= bh1730.o
 obj-$(CONFIG_BH1745)		+= bh1745.o
 obj-$(CONFIG_BH1750)		+= bh1750.o
 obj-$(CONFIG_BH1780)		+= bh1780.o
diff --git a/drivers/iio/light/bh1730.c b/drivers/iio/light/bh1730.c
new file mode 100644
index 000000000000..c93290ff5661
--- /dev/null
+++ b/drivers/iio/light/bh1730.c
@@ -0,0 +1,686 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ROHM BH1730 ambient light sensor driver
+ *
+ * Copyright (c) 2021 CTCaer <ctcaer@gmail.com>
+ *
+ * Based on previous iio BH1730FVC drivers from:
+ * Copyright (c) 2018 Google, Inc.
+ * Author: Pierre Bourdon <delroth@google.com>
+ *
+ * Copyright (C) 2012 Samsung Electronics. All rights reserved.
+ * Author: Won Huh <won.huh@samsung.com>
+ *
+ * Data sheets:
+ *  http://www.rohm.com/web/global/datasheet/BH1730FVC/bh1730fvc-e
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/time.h>
+#include <linux/regulator/consumer.h>
+
+#define BH1730_NAME	"bh1730fvc"
+
+#define BH1730_CMD_BIT BIT(7)
+
+#define BH1730_REG_CONTROL	0x00
+#define BH1730_REG_TIMING	0x01
+#define BH1730_REG_INTERRUPT	0x02
+#define BH1730_REG_THLLOW	0x03
+#define BH1730_REG_THLHIGH	0x04
+#define BH1730_REG_THHLOW	0x05
+#define BH1730_REG_THHHIGH	0x06
+#define BH1730_REG_GAIN		0x07
+#define BH1730_REG_ID		0x12
+#define BH1730_REG_DATA0LOW	0x14
+#define BH1730_REG_DATA0HIGH	0x15
+#define BH1730_REG_DATA1LOW	0x16
+#define BH1730_REG_DATA1HIGH	0x17
+
+#define BH1730_CONTROL_POWER		BIT(0)
+#define BH1730_CONTROL_ADC_EN		BIT(1)
+#define BH1730_CONTROL_DATA0_ONLY	BIT(2)
+#define BH1730_CONTROL_ONE_TIME		BIT(3)
+#define BH1730_CONTROL_ADC_VALID	BIT(4)
+#define BH1730_CONTROL_INTR		BIT(5)
+
+#define BH1730_INTERNAL_CLOCK_NS	2800
+/* BH1730_INTERNAL_CLOCK_MS * 714 */
+#define BH1730_ADC_CALC_DELAY_US	2000
+/* BH1730_INTERNAL_CLOCK_MS * 964 */
+#define BH1730_ITIME_TO_US		2700
+
+#define BH1730_DEFAULT_INTEG_CYCLE	38
+#define BH1730_DEFAULT_ITIME_MS		100
+
+#define BH1730_POWER_ON_DELAY_US	10000
+
+#define BH1730_MAX_MEASURED_LUX		100000
+
+enum bh1730_gain {
+	BH1730_GAIN_1X = 0,
+	BH1730_GAIN_2X,
+	BH1730_GAIN_64X,
+	BH1730_GAIN_128X,
+};
+#define BH1730_MAX_GAIN_MULTIPLIER 128
+
+struct gain_coeff_t {
+	u32 cl;
+	u32 fl;
+};
+
+struct opt_win_coeff_t {
+	u32 rc;
+	u32 cv;
+	u32 ci;
+};
+
+struct lux_cal_data_t {
+	struct gain_coeff_t *gain_coeff;
+	struct opt_win_coeff_t *opt_win_coeff;
+	u32 opt_win_coeff_count;
+	u32 itime_cycle;
+	u32 mul;
+};
+
+/*
+ * No optical window or optical window that has flat transmittance
+ * from visible light to infrared light.
+ */
+static struct opt_win_coeff_t def_lux_coeff[] = {
+	{  260, 1290, 2733 },
+	{  550,  795,  859 },
+	{ 1090,  510,  345 },
+	{ 2130,  276,  130 }
+};
+
+static struct gain_coeff_t def_gain_coeff[] = {
+	{ 3000,    -1 }, /* 1x */
+	{ 2000,  9800 }, /* 2x */
+	{   15, 60000 }, /* 64x */
+	{    0,  1300 }  /* 128x */
+};
+
+static struct lux_cal_data_t def_lux_data = {
+	.gain_coeff = def_gain_coeff,
+	.opt_win_coeff = def_lux_coeff,
+	.opt_win_coeff_count = ARRAY_SIZE(def_lux_coeff),
+	.itime_cycle = BH1730_DEFAULT_INTEG_CYCLE,
+	.mul = 1000
+};
+
+struct bh1730_data {
+	struct i2c_client *client;
+	struct lux_cal_data_t cal;
+	struct regulator *reg_vdd;
+	struct regulator *reg_vid;
+	enum bh1730_gain gain;
+	u32 itime_us;
+	u32 tmt_us;
+};
+
+static int bh1730_read_word(struct bh1730_data *bh1730, u8 reg)
+{
+	int ret = i2c_smbus_read_word_data(bh1730->client,
+					   BH1730_CMD_BIT | reg);
+	if (ret < 0)
+		dev_err(&bh1730->client->dev,
+			"i2c read failed error %d, register %01x\n",
+			ret, reg);
+
+	return ret;
+}
+
+static int bh1730_write(struct bh1730_data *bh1730, u8 reg, u8 val)
+{
+	int ret = i2c_smbus_write_byte_data(bh1730->client,
+					    BH1730_CMD_BIT | reg,
+					    val);
+	if (ret < 0)
+		dev_err(&bh1730->client->dev,
+			"i2c write failed error %d, register %01x\n",
+			ret, reg);
+
+	return ret;
+}
+
+static int bh1730_gain_multiplier(struct bh1730_data *bh1730)
+{
+	int multiplier;
+
+	switch (bh1730->gain) {
+	case BH1730_GAIN_1X:
+		multiplier = 1;
+		break;
+	case BH1730_GAIN_2X:
+		multiplier = 2;
+		break;
+	case BH1730_GAIN_64X:
+		multiplier = 64;
+		break;
+	case BH1730_GAIN_128X:
+		multiplier = 128;
+		break;
+	default:
+		multiplier = -EINVAL;
+		break;
+	}
+
+	if (multiplier < 0) {
+		dev_warn(&bh1730->client->dev,
+			 "invalid gain multiplier settings: %d\n",
+			 bh1730->gain);
+		bh1730->gain = BH1730_GAIN_1X;
+		multiplier = 1;
+	}
+
+	return multiplier;
+}
+
+static int bh1730_set_gain(struct bh1730_data *bh1730, enum bh1730_gain gain)
+{
+	int ret = bh1730_write(bh1730, BH1730_REG_GAIN, gain);
+
+	if (ret < 0)
+		return ret;
+
+	bh1730->gain = gain;
+
+	return 0;
+}
+
+static int bh1730_itime_us(struct bh1730_data *bh1730, int cycle)
+{
+	return (BH1730_ITIME_TO_US * cycle);
+}
+
+
+static int bh1730_set_integration_time_cycle(struct bh1730_data *bh1730,
+					  u32 cycle)
+{
+	int ret, itime;
+
+	itime = 256 - cycle;
+
+	/* ITIME == 0 is reserved for manual integration mode. */
+	if (itime <= 0 || itime > 255) {
+		dev_warn(&bh1730->client->dev,
+		"integration time out of range: %d cycles\n",
+		 cycle);
+
+		return -ERANGE;
+	}
+
+	ret = bh1730_write(bh1730, BH1730_REG_TIMING, itime);
+	if (ret < 0)
+		return ret;
+
+	bh1730->itime_us = bh1730_itime_us(bh1730, cycle);
+	bh1730->tmt_us = bh1730->itime_us + BH1730_ADC_CALC_DELAY_US;
+
+	return 0;
+}
+
+static int bh1730_adjust_gain(struct bh1730_data *bh1730)
+{
+	int visible, ir, highest, gain, ret;
+
+	visible = bh1730_read_word(bh1730, BH1730_REG_DATA0LOW);
+	if (visible < 0)
+		return visible;
+
+	ir = bh1730_read_word(bh1730, BH1730_REG_DATA1LOW);
+	if (ir < 0)
+		return ir;
+
+	highest = max(visible, ir);
+
+	/* Adjust gain based on sensitivity calibration */
+	gain = bh1730->gain;
+	if (highest > bh1730->cal.gain_coeff[gain].fl &&
+	    gain != BH1730_GAIN_1X) {
+		gain--; /* Decrease sensitivity */
+	} else if (highest < bh1730->cal.gain_coeff[gain].cl &&
+		   gain != BH1730_GAIN_128X) {
+		gain++; /* Increase sensitivity */
+	}
+
+	/* Clamp to proper gain values */
+	if (gain < 0)
+		gain = BH1730_GAIN_1X;
+	else if (gain > BH1730_GAIN_128X)
+		gain = BH1730_GAIN_128X;
+
+	if (gain != bh1730->gain) {
+		ret = bh1730_set_gain(bh1730, gain);
+		if (ret < 0)
+			return ret;
+
+		usleep_range(bh1730->tmt_us, bh1730->tmt_us + 1000);
+	}
+
+	return 0;
+}
+
+static int bh1730_get_lux(struct bh1730_data *bh1730)
+{
+	int i, visible, ir;
+	struct opt_win_coeff_t *opt_win_coeff;
+	u64 lux = 0;
+
+	visible = bh1730_read_word(bh1730, BH1730_REG_DATA0LOW);
+
+	/* If visible is 0, skip calculations */
+	if (visible <= 0)
+		return visible;
+
+	ir = bh1730_read_word(bh1730, BH1730_REG_DATA1LOW);
+	if (ir < 0)
+		return ir;
+
+	/* Calibrate based on optical window */
+	for (i = 0; i < bh1730->cal.opt_win_coeff_count; i++) {
+		opt_win_coeff = &bh1730->cal.opt_win_coeff[i];
+		if (1000 * ir / visible < opt_win_coeff->rc) {
+			lux = ((u64)opt_win_coeff->cv * visible) -
+				   (opt_win_coeff->ci * ir);
+			break;
+		}
+	}
+
+	/* Calculate lux */
+	lux *= BH1730_DEFAULT_ITIME_MS;
+	lux /= bh1730_gain_multiplier(bh1730) * bh1730->itime_us;
+	lux = (lux * bh1730->cal.mul) / 1000;
+
+	if (lux > BH1730_MAX_MEASURED_LUX)
+		lux = BH1730_MAX_MEASURED_LUX;
+
+	return (int)lux;
+}
+
+static int bh1730_power_ctrl(struct bh1730_data *bh1730, bool enable)
+{
+	struct device *dev = &bh1730->client->dev;
+	static bool enabled;
+	int ret = 0;
+
+	if (enabled == enable)
+		return ret;
+
+	if (enable) {
+		if (!IS_ERR_OR_NULL(bh1730->reg_vdd)) {
+			ret = regulator_enable(bh1730->reg_vdd);
+			if (ret) {
+				dev_err(dev, "%s: Failed to enable vdd: %d\n",
+					__func__, ret);
+				return ret;
+			}
+		}
+
+		if (!IS_ERR_OR_NULL(bh1730->reg_vid)) {
+			ret = regulator_enable(bh1730->reg_vid);
+			if (ret) {
+				dev_err(dev, "%s: Failed to enable vid: %d\n",
+					__func__, ret);
+				return ret;
+			}
+		}
+
+		usleep_range(BH1730_POWER_ON_DELAY_US, BH1730_POWER_ON_DELAY_US + 1000);
+	} else {
+		if (!IS_ERR_OR_NULL(bh1730->reg_vdd)) {
+			ret = regulator_disable(bh1730->reg_vdd);
+			if (ret) {
+				dev_err(dev, "%s: Failed to disable vdd: %d\n",
+					__func__, ret);
+				return ret;
+			}
+		}
+
+		if (!IS_ERR_OR_NULL(bh1730->reg_vid)) {
+			ret = regulator_disable(bh1730->reg_vid);
+			if (ret) {
+				dev_err(dev, "%s: Failed to disable vid: %d\n",
+					__func__, ret);
+				return ret;
+			}
+		}
+	}
+
+	enabled = enable;
+
+	return ret;
+}
+
+static int bh1730_power_on(struct bh1730_data *bh1730)
+{
+	int ret = bh1730_power_ctrl(bh1730, true);
+
+	if (ret < 0)
+		return ret;
+
+	return bh1730_write(bh1730, BH1730_REG_CONTROL,
+			    BH1730_CONTROL_POWER | BH1730_CONTROL_ADC_EN);
+}
+
+static int bh1730_init_config(struct bh1730_data *bh1730)
+{
+	int ret;
+
+	ret = bh1730_set_gain(bh1730, BH1730_GAIN_64X);
+	if (ret < 0)
+		return ret;
+
+	return bh1730_set_integration_time_cycle(bh1730,
+						bh1730->cal.itime_cycle);
+}
+
+static int bh1730_power_off(struct bh1730_data *bh1730)
+{
+	int ret = bh1730_write(bh1730, BH1730_REG_CONTROL, 0);
+
+	if (ret < 0)
+		return ret;
+
+	return bh1730_power_ctrl(bh1730, false);
+}
+
+static int bh1730_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	struct bh1730_data *bh1730 = iio_priv(indio_dev);
+	int data_reg, ret;
+
+	ret = bh1730_adjust_gain(bh1730);
+	if (ret < 0)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = bh1730_get_lux(bh1730);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->channel2) {
+		case IIO_MOD_LIGHT_CLEAR:
+			data_reg = BH1730_REG_DATA0LOW;
+			break;
+		case IIO_MOD_LIGHT_IR:
+			data_reg = BH1730_REG_DATA1LOW;
+			break;
+		default:
+			return -EINVAL;
+		}
+		ret = bh1730_read_word(bh1730, data_reg);
+		if (ret < 0)
+			return ret;
+		ret = ret * 1000 / bh1730_gain_multiplier(bh1730);
+		*val = ret / 1000;
+		*val2 = (ret % 1000) * 1000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_INT_TIME:
+		*val = 0;
+		*val2 = bh1730->itime_us;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bh1730_parse_dt(struct bh1730_data *bh1730, struct device_node *dn)
+{
+	struct device *dev = &bh1730->client->dev;
+	int ret;
+	u32 *opt_win_coeff = NULL;
+	u32 *gain_coeff = NULL;
+	int opt_win_coeff_count = 0, gain_coeff_count = 0, cycle = 0, mul = 0;
+
+	memcpy(&bh1730->cal, &def_lux_data, sizeof(struct lux_cal_data_t));
+
+	if (dn) {
+		/* Get regulators */
+		bh1730->reg_vdd = regulator_get(dev, "als-vdd");
+		if (IS_ERR_OR_NULL(bh1730->reg_vdd)) {
+			bh1730->reg_vdd = NULL;
+			dev_warn(dev, "failed to get als-vdd");
+		}
+
+		bh1730->reg_vid = regulator_get(dev, "als-vid");
+		if (IS_ERR_OR_NULL(bh1730->reg_vid)) {
+			bh1730->reg_vid = NULL;
+			dev_warn(dev, "failed to get als-vid");
+		}
+
+		/* Get calibration */
+		ret = of_property_read_u32(dn,
+				"rohm,integration-cycle", &cycle);
+		if (ret < 0)
+			goto out;
+
+		ret = of_property_read_u32(dn,
+				"rohm,lux-multiplier", &mul);
+		if (ret < 0)
+			goto out;
+
+		if (cycle == 0 || mul == 0)
+			goto out;
+
+		/* Get optical window coefficients */
+		opt_win_coeff_count = of_property_count_elems_of_size(dn,
+					"rohm,opt-win-coeff", sizeof(u32));
+		if (opt_win_coeff_count > 0) {
+			opt_win_coeff = devm_kzalloc(dev,
+						sizeof(u32) * opt_win_coeff_count,
+						GFP_KERNEL);
+			if (!opt_win_coeff) {
+				dev_err(dev, "failed to allocate mem for opt_win_coeff");
+				return -ENOMEM;
+			}
+
+			ret = of_property_read_u32_array(dn, "rohm,opt-win-coeff",
+					opt_win_coeff, opt_win_coeff_count);
+
+			if (ret) {
+				devm_kfree(dev, opt_win_coeff);
+				goto out;
+			}
+		}
+
+		/* Get gain sensitivity coefficients */
+		gain_coeff_count = of_property_count_elems_of_size(dn,
+					"rohm,gain-coeff", sizeof(u32));
+
+		if (gain_coeff_count == 8) { /* 2 for each gain supported */
+			gain_coeff = devm_kzalloc(dev,
+					sizeof(u32) * gain_coeff_count,
+					GFP_KERNEL);
+			if (!gain_coeff) {
+				dev_err(dev, "failed to allocate mem for gain_coeff");
+				return -ENOMEM;
+			}
+
+			ret = of_property_read_u32_array(dn, "rohm,gain-coeff",
+					gain_coeff, gain_coeff_count);
+			if (ret) {
+				if (opt_win_coeff)
+					devm_kfree(dev, opt_win_coeff);
+				devm_kfree(dev, gain_coeff);
+				goto out;
+			}
+		}
+
+		if (opt_win_coeff) {
+			bh1730->cal.opt_win_coeff =
+					(struct opt_win_coeff_t *)opt_win_coeff;
+			bh1730->cal.opt_win_coeff_count =
+					opt_win_coeff_count /
+					(sizeof(struct opt_win_coeff_t) /
+					sizeof(u32));
+		}
+
+		if (gain_coeff)
+			bh1730->cal.gain_coeff = (struct gain_coeff_t *)gain_coeff;
+
+		bh1730->cal.itime_cycle = cycle;
+		bh1730->cal.mul = mul;
+
+		return 0;
+	}
+
+out:
+	dev_info(&bh1730->client->dev, "using default calibration");
+
+	return 0;
+}
+
+static const struct iio_info bh1730_info = {
+	.read_raw = bh1730_read_raw,
+};
+
+static const struct iio_chan_spec bh1730_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
+				      BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_CLEAR,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_IR,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+};
+
+static int bh1730_probe(struct i2c_client *client)
+{
+	struct bh1730_data *bh1730;
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
+		return -EIO;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*bh1730));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	bh1730 = iio_priv(indio_dev);
+	bh1730->client = client;
+	i2c_set_clientdata(client, indio_dev);
+
+	ret = bh1730_parse_dt(bh1730, client->dev.of_node);
+	if (ret < 0)
+		return ret;
+
+	ret = bh1730_power_on(bh1730);
+	if (ret < 0)
+		return ret;
+
+	ret = bh1730_init_config(bh1730);
+	if (ret < 0)
+		return ret;
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &bh1730_info;
+	indio_dev->name = "bh1730";
+	indio_dev->channels = bh1730_channels;
+	indio_dev->num_channels = ARRAY_SIZE(bh1730_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto out_power_off;
+
+	return 0;
+
+out_power_off:
+	dev_info(&client->dev, "%s: failed\n", __func__);
+	bh1730_power_off(bh1730);
+	return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int bh1730_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct bh1730_data *bh1730 = iio_priv(indio_dev);
+
+	bh1730_power_off(bh1730);
+
+	return 0;
+}
+
+static int bh1730_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct bh1730_data *bh1730 = iio_priv(indio_dev);
+	int ret;
+
+	ret = bh1730_power_on(bh1730);
+	if (ret < 0)
+		return ret;
+
+	return bh1730_init_config(bh1730);
+}
+
+static SIMPLE_DEV_PM_OPS(bh1730_pm_ops, bh1730_suspend, bh1730_resume);
+#endif
+
+static void bh1730_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct bh1730_data *bh1730 = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	bh1730_power_off(bh1730);
+}
+
+static const struct i2c_device_id bh1730_i2c_device_id[] = {
+	{ BH1730_NAME, 0 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, bh1730_i2c_device_id);
+
+static const struct of_device_id of_bh1730_match[] = {
+	{ .compatible = "rohm,bh1730fvc" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_bh1730_match);
+
+static struct i2c_driver bh1730_driver = {
+	.probe = bh1730_probe,
+	.remove = bh1730_remove,
+	.driver = {
+		.name = BH1730_NAME,
+		.owner		= THIS_MODULE,
+		.of_match_table = of_bh1730_match,
+#ifdef CONFIG_PM_SLEEP
+		.pm		= &bh1730_pm_ops,
+#endif
+	},
+	.id_table = bh1730_i2c_device_id,
+};
+module_i2c_driver(bh1730_driver);
+
+MODULE_AUTHOR("CTCaer <ctcaer@gmail.com>");
+MODULE_DESCRIPTION("ROHM BH1730FVC driver");
+MODULE_LICENSE("GPL v2");

-- 
2.54.0

Re: [PATCH 0/2] iio: light: Add ROHM BH1730FVC ambient light sensor driver

[Andy Shevchenko]

On Mon, May 11, 2026 at 01:09:48AM +0700, Alexandre Hamamdjian via B4 Relay wrote:
> Add a driver and devicetree binding for the ROHM BH1730FVC ambient
> light sensor. This sensor is found on the Nintendo Switch console,
> where it is used by the system for automatic display brightness
> adjustment.

Always for a new driver put a summary of the study of the existing drivers
in the area and explain "Why do we need a brand new driver? Can't we have
an existing driver to be extended to cover this HW?"

> ---
> CTCaer (2):

No aliases, use yours real name

>       dt-bindings: iio: light: Add ROHM BH1730FVC binding
>       iio: light: bh1730: Add bh1730 light sensor driver

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 2/2] iio: light: bh1730: Add bh1730 light sensor driver

[Andy Shevchenko]

On Mon, May 11, 2026 at 01:09:50AM +0700, Alexandre Hamamdjian via B4 Relay wrote:

> Add a driver for the ROHM BH1730FVC ambient light sensor. The device
> is a 16-bit I2C digital sensor with separate visible and infrared
> photodiodes, four selectable gains (1x/2x/64x/128x) and a programmable
> integration time.
> 
> The driver exposes illuminance via IIO, performs runtime gain and
> integration-time tracking to keep the ADC in range, and supports
> optional als-vdd / als-vid regulators. Per-board lux calibration data
> (integration cycles, lux multiplier, optical-window coefficients, and
> gain sensitivity coefficients) can be supplied via device tree;
> sensible defaults are used otherwise.

> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/module.h>

> +#include <linux/of.h>

Regular drivers do not to be OF-centric. This won't allow them to be used
outside of OF-only platforms.

> +#include <linux/time.h>
> +#include <linux/regulator/consumer.h>

Missing a lot of headers, follow IWYU.

...


Here I stop my review and recommend you first to review others' patches and
learn from other reviews. This will help you a lot with avoiding typical
mistakes.

Also Matti would be the best reviewer for this as he worked (still works?)
for ROHM and knows the HW a bit more than average kernel developer.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 2/2] iio: light: bh1730: Add bh1730 light sensor driver

[Andy Shevchenko]

On Sun, May 10, 2026 at 09:18:48PM +0300, Andy Shevchenko wrote:
> On Mon, May 11, 2026 at 01:09:50AM +0700, Alexandre Hamamdjian via B4 Relay wrote:
> 
> > Add a driver for the ROHM BH1730FVC ambient light sensor. The device
> > is a 16-bit I2C digital sensor with separate visible and infrared
> > photodiodes, four selectable gains (1x/2x/64x/128x) and a programmable
> > integration time.
> > 
> > The driver exposes illuminance via IIO, performs runtime gain and
> > integration-time tracking to keep the ADC in range, and supports
> > optional als-vdd / als-vid regulators. Per-board lux calibration data
> > (integration cycles, lux multiplier, optical-window coefficients, and
> > gain sensitivity coefficients) can be supplied via device tree;
> > sensible defaults are used otherwise.
> 
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/module.h>
> 
> > +#include <linux/of.h>
> 
> Regular drivers do not to be OF-centric. This won't allow them to be used
> outside of OF-only platforms.
> 
> > +#include <linux/time.h>
> > +#include <linux/regulator/consumer.h>
> 
> Missing a lot of headers, follow IWYU.

...

> Here I stop my review and recommend you first to review others' patches and
> learn from other reviews. This will help you a lot with avoiding typical
> mistakes.
> 
> Also Matti would be the best reviewer for this as he worked (still works?)
> for ROHM and knows the HW a bit more than average kernel developer.

Forgot to Cc Matti since I mentioned him. Now done.

-- 
With Best Regards,
Andy Shevchenko