iio: light: add support for Broadcom APDS9999

Add Device Tree binding for the Broadcom APDS9999 ambient light and proximity sensor.

The APDS9999 features individual R, G, B, and IR channels with a green channel that uses optical coating to approximate the human eye spectral response for ALS/lux measurements. Proximity and RGB functionality are not yet implemented in the driver.

Signed-off-by Jose A. Perez de Azpillaga <[email protected]>

---
 .../bindings/iio/light/brcm,apds9999.yaml     | 53 +++++++++++++++++++
 MAINTAINERS                                   |  6 +++
 2 files changed, 59 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/brcm,apds9999.yaml

Documentation/devicetree/bindings/iio/light/brcm,apds9999.yaml new file +4 -0

new file mode 100644
index 000000000000..759fe0151549
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/light/brcm,apds9999.yaml#

Documentation/devicetree/bindings/iio/light/brcm,apds9999.yaml new file +39 -0

+
+  Datasheet: https://docs.broadcom.com/docs/APDS-9999-DS
+
+properties:
+  compatible:
+    enum:
+      - brcm,apds9999
+
+  reg:
+    maxItems: 1
+
+  vdd-supply: true
+
+  vled-supply:
+    description: VCSEL power supply
+
+  interrupts:
+    maxItems: 1
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        light-sensor@52 {
+            compatible = "brcm,apds9999";
+            reg = <0x52>;
+            vdd-supply = <&vdd_reg>;
+            vled-supply = <&vled_reg>;
+        };
+    };

MAINTAINERS +0 -0

index 1aa9c989973f..64c8cf2601e8 100644

MAINTAINERS +1 -0

+
 AVIA HX711 ANALOG DIGITAL CONVERTER IIO DRIVER
 M:	Andreas Klinger <[email protected]>
 L:	[email protected]

Add IIO driver for Broadcom APDS9999 ambient light sensor.

The APDS9999 is a digital proximity and RGB sensor with ALS capability. This driver implements the ALS/Lux functionality using the green channel, which uses optical coating technology to approximate the human eye spectral response.

Proximity (PS) and RGB color features are not yet implemented.

Signed-off-by Jose A. Perez de Azpillaga <[email protected]>

drivers/iio/light/apds9999.c new file +18 -0

+	int ret;
+
+	ret = devm_add_action_or_reset(dev, apds9999_standby, client);
+	if (ret)
+		return ret;
+
+	guard(mutex)(&data->lock);
+
+	reg = FIELD_PREP(APDS9999_LS_RES_MASK, APDS9999_RES_18BIT) |
+	      FIELD_PREP(APDS9999_LS_RATE_MASK, APDS9999_RATE_100_MS);
+	ret = i2c_smbus_write_byte_data(client, APDS9999_REG_LS_MEAS_RATE, reg);
+	if (ret)
+		return ret;
+	data->als_res = APDS9999_RES_18BIT;
+	data->als_rate = APDS9999_RATE_100_MS;
+
+	ret = i2c_smbus_write_byte_data(client, APDS9999_REG_LS_GAIN,
+					APDS9999_GAIN_3X);

drivers/iio/light/apds9999.c new file +9 -0

+}
+
+static int apds9999_read_channel(struct apds9999_data *data, u8 reg, u32 *counts)
+{
+	struct i2c_client *client = data->client;
+	u8 buf[3];
+	int ret, tries;
+
+	guard(mutex)(&data->lock);

drivers/iio/light/apds9999.c new file +27 -0

+		if (ret < 0)
+			return ret;
+		if (ret & APDS9999_MAIN_STATUS_LS_DATA)
+			break;
+		fsleep(20000);
+	}
+
+	if (tries < 0)
+		return -ETIMEDOUT;
+
+	ret = i2c_smbus_read_i2c_block_data(client, reg, sizeof(buf), buf);
+	if (ret < 0)
+		return ret;
+	if (ret != sizeof(buf))
+		return -EIO;
+
+	*counts = get_unaligned_le24(buf) & GENMASK(19, 0);
+	return 0;
+}
+
+static int apds9999_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct apds9999_data *data = iio_priv(indio_dev);
+	int gain, itime_us;
+	u64 scale_nano;

drivers/iio/light/apds9999.c new file +55 -0

+
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * Scale (lux per count) = 54 / (gain * integration_time_ms)
+		 *
+		 * The constant 54 is derived from the datasheet table:
+		 *   at gain = 3x, itime = 100 ms -> 0.180 lux/count
+		 *   -> C = 0.180 * 3 * 100 = 54
+		 *
+		 * Expressed as IIO_VAL_INT_PLUS_NANO.
+		 */
+		gain = apds9999_gains[data->als_gain_idx];
+		itime_us = apds9999_itimes_us[data->als_res];
+
+		/* scale_nano = 54e12 / (gain * itime_us) nano-lux/count */
+		scale_nano = div_u64(54000000000000ULL, (u32)(gain * itime_us));
+		*val = (int)(scale_nano / NSEC_PER_SEC);
+		*val2 = (int)(scale_nano % NSEC_PER_SEC);
+		return IIO_VAL_INT_PLUS_NANO;
+
+	case IIO_CHAN_INFO_INT_TIME:
+		*val = 0;
+		*val2 = apds9999_itimes_us[data->als_res];
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec apds9999_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_RED,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+		.address = APDS9999_REG_LS_DATA_RED_0,
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_GREEN,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+		.address = APDS9999_REG_LS_DATA_GREEN_0,
+	},
+	{
+		.type = IIO_INTENSITY,

drivers/iio/light/apds9999.c new file +23 -0

+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, apds9999_id);
+
+static const struct of_device_id apds9999_of_match[] = {
+	{ .compatible = "brcm,apds9999" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, apds9999_of_match);
+
+static struct i2c_driver apds9999_driver = {
+	.driver = {
+		.name = "apds9999",
+		.of_match_table = apds9999_of_match,
+	},
+	.probe = apds9999_probe,
+	.id_table = apds9999_id,
+};
+module_i2c_driver(apds9999_driver);
+
+MODULE_AUTHOR("Jose A. Perez de Azpillaga <[email protected]>");
+MODULE_DESCRIPTION("APDS-9999 Lux Light Sensor IIO Driver");
+MODULE_LICENSE("GPL");

Add IIO driver for Broadcom APDS9999 ambient light sensor.

The APDS9999 is a digital proximity and RGB sensor with ALS capability. This driver implements the ALS/Lux functionality using the green channel, which uses optical coating technology to approximate the human eye spectral response.

Proximity (PS) and RGB color features are not yet implemented.

drivers/iio/light/apds9999.c new file +8 -0

+
+static const int apds9999_gains[] = {
+	[APDS9999_GAIN_1X]  = 1,
+	[APDS9999_GAIN_3X]  = 3,
+	[APDS9999_GAIN_6X]  = 6,
+	[APDS9999_GAIN_9X]  = 9,
+	[APDS9999_GAIN_18X] = 18,
+};

drivers/iio/light/apds9999.c new file +5 -0

+	[APDS9999_RES_19BIT] = 200000,
+	[APDS9999_RES_18BIT] = 100000,
+	[APDS9999_RES_17BIT] =  50000,
+	[APDS9999_RES_16BIT] =  25000,
+	[APDS9999_RES_13BIT] =   3125,

drivers/iio/light/apds9999.c new file +28 -0

+};
+
+struct apds9999_data {
+	struct i2c_client *client;
+	/* lock: protects als_gain_idx, als_res, als_rate */
+	struct mutex lock;
+	int als_gain_idx;
+	int als_res;
+	int als_rate;
+};
+
+static void apds9999_standby(void *client)
+{
+	i2c_smbus_write_byte_data(client, APDS9999_REG_MAIN_CTRL, 0);
+}
+
+static int apds9999_init(struct apds9999_data *data)
+{
+	struct device *dev = &data->client->dev;
+	struct i2c_client *client = data->client;
+	u8 reg;
+	int ret;
+
+	ret = devm_add_action_or_reset(dev, apds9999_standby, client);
+	if (ret)
+		return ret;
+
+	guard(mutex)(&data->lock);

drivers/iio/light/apds9999.c new file +107 -0

+
+	ret = i2c_smbus_write_byte_data(client, APDS9999_REG_LS_GAIN,
+					APDS9999_GAIN_3X);
+	if (ret)
+		return ret;
+	data->als_gain_idx = APDS9999_GAIN_3X;
+
+	ret = i2c_smbus_write_byte_data(client, APDS9999_REG_MAIN_CTRL,
+					APDS9999_MAIN_CTRL_LS_EN);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int apds9999_read_channel(struct apds9999_data *data, u8 reg, u32 *counts)
+{
+	struct i2c_client *client = data->client;
+	u8 buf[3];
+	int ret, tries;
+
+	guard(mutex)(&data->lock);
+
+	/*
+	 * Poll MAIN_STATUS for new data.  Timeout: ~2 integration periods
+	 * plus margin.  Each try sleeps 20 ms.
+	 */
+	tries = max(2, (apds9999_itimes_us[data->als_res] * 2) / 20000);
+
+	while (tries--) {
+		ret = i2c_smbus_read_byte_data(client,
+						APDS9999_REG_MAIN_STATUS);
+		if (ret < 0)
+			return ret;
+		if (ret & APDS9999_MAIN_STATUS_LS_DATA)
+			break;
+		fsleep(20000);
+	}
+
+	if (tries < 0)
+		return -ETIMEDOUT;
+
+	ret = i2c_smbus_read_i2c_block_data(client, reg, sizeof(buf), buf);
+	if (ret < 0)
+		return ret;
+	if (ret != sizeof(buf))
+		return -EIO;
+
+	*counts = get_unaligned_le24(buf) & GENMASK(19, 0);
+	return 0;
+}
+
+static int apds9999_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct apds9999_data *data = iio_priv(indio_dev);
+	int gain, itime_us;
+	u64 scale_nano;
+	u32 counts;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_LIGHT:
+			ret = apds9999_read_channel(data,
+						    APDS9999_REG_LS_DATA_GREEN_0,
+						    &counts);
+			break;
+		case IIO_INTENSITY:
+			ret = apds9999_read_channel(data, chan->address,
+						    &counts);
+			break;
+		default:
+			return -EINVAL;
+		}
+		if (ret)
+			return ret;
+		*val = (int)counts;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * Scale (lux per count) = 54 / (gain * integration_time_ms)
+		 *
+		 * The constant 54 is derived from the datasheet table:
+		 *   at gain = 3x, itime = 100 ms -> 0.180 lux/count
+		 *   -> C = 0.180 * 3 * 100 = 54
+		 *
+		 * Expressed as IIO_VAL_INT_PLUS_NANO.
+		 */
+		gain = apds9999_gains[data->als_gain_idx];
+		itime_us = apds9999_itimes_us[data->als_res];
+
+		/* scale_nano = 54e12 / (gain * itime_us) nano-lux/count */
+		scale_nano = div_u64(54000000000000ULL, (u32)(gain * itime_us));
+		*val = (int)(scale_nano / NSEC_PER_SEC);
+		*val2 = (int)(scale_nano % NSEC_PER_SEC);
+		return IIO_VAL_INT_PLUS_NANO;
+
+	case IIO_CHAN_INFO_INT_TIME:
+		*val = 0;
+		*val2 = apds9999_itimes_us[data->als_res];
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	default:

drivers/iio/light/apds9999.c new file +22 -0

+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+		.address = APDS9999_REG_LS_DATA_RED_0,
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_GREEN,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+		.address = APDS9999_REG_LS_DATA_GREEN_0,
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_BLUE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+		.address = APDS9999_REG_LS_DATA_BLUE_0,
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,

drivers/iio/light/apds9999.c new file +71 -0

+
+static int apds9999_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct apds9999_data *data;
+	struct iio_dev *indio_dev;
+	int ret, part_id;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+
+	ret = devm_mutex_init(dev, &data->lock);
+	if (ret)
+		return ret;
+
+	part_id = i2c_smbus_read_byte_data(client, APDS9999_REG_PART_ID);
+	if (part_id < 0)
+		return dev_err_probe(dev, part_id,
+				     "failed to read PART_ID\n");
+	if (part_id != APDS9999_PART_ID)
+		dev_info(dev, "unexpected PART_ID 0x%02x (expected 0x%02x)\n",
+			 part_id, APDS9999_PART_ID);
+
+	ret = apds9999_init(data);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to initialize device\n");
+
+	indio_dev->name = "apds9999";
+	indio_dev->info = &apds9999_info;
+	indio_dev->channels = apds9999_channels;
+	indio_dev->num_channels = ARRAY_SIZE(apds9999_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to register IIO device\n");
+
+	return 0;
+}
+
+static const struct i2c_device_id apds9999_id[] = {
+	{ "apds9999" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, apds9999_id);
+
+static const struct of_device_id apds9999_of_match[] = {
+	{ .compatible = "brcm,apds9999" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, apds9999_of_match);
+
+static struct i2c_driver apds9999_driver = {
+	.driver = {
+		.name = "apds9999",
+		.of_match_table = apds9999_of_match,
+	},
+	.probe = apds9999_probe,
+	.id_table = apds9999_id,
+};
+module_i2c_driver(apds9999_driver);
+
+MODULE_AUTHOR("Jose A. Perez de Azpillaga <[email protected]>");
+MODULE_DESCRIPTION("APDS-9999 Lux Light Sensor IIO Driver");
+MODULE_LICENSE("GPL");

Quoted 9 lines · Jose A. Perez de Azpillaga

Add IIO driver for Broadcom APDS9999 ambient light sensor.

The APDS9999 is a digital proximity and RGB sensor with ALS capability. This driver implements the ALS/Lux functionality using the green channel, which uses optical coating technology to approximate the human eye spectral response.

Proximity (PS) and RGB color features are not yet implemented.

drivers/iio/light/apds9999.c line 46

Quoted 7 lines

drivers/iio/light/apds9999.c new file +7 -0

+enum apds9999_gain {
+	APDS9999_GAIN_1X = 0,
+	APDS9999_GAIN_3X = 1,
+	APDS9999_GAIN_6X = 2,
+	APDS9999_GAIN_9X = 3,
+	APDS9999_GAIN_18X = 4,
+};  

Giving the natural values of enum explicitly just seems like noise IMHO. I wasted time looking for an anomaly.

Quoted 13 lines · On Sat, 16 May 2026 10:28:47 -0500 David Lechner <[email protected]> wrote:

Quoted 9 lines · Jose A. Perez de Azpillaga

Add IIO driver for Broadcom APDS9999 ambient light sensor.

The APDS9999 is a digital proximity and RGB sensor with ALS capability. This driver implements the ALS/Lux functionality using the green channel, which uses optical coating technology to approximate the human eye spectral response.

Proximity (PS) and RGB color features are not yet implemented.

Quoted 10 lines

drivers/iio/light/apds9999.c line 46

Quoted 7 lines

drivers/iio/light/apds9999.c new file +7 -0

+enum apds9999_gain {
+	APDS9999_GAIN_1X = 0,
+	APDS9999_GAIN_3X = 1,
+	APDS9999_GAIN_6X = 2,
+	APDS9999_GAIN_9X = 3,
+	APDS9999_GAIN_18X = 4,
+};  

Giving the natural values of enum explicitly just seems like noise IMHO. I wasted time looking for an anomaly.

I tend to ask for this when they are hardware field values to make the point the values matter rather than just being an enum. I'm not that fussed though.

Jonathan

Quoted 27 lines · Jonathan Cameron

Quoted 23 lines · On Sat, 16 May 2026 10:28:47 -0500 David Lechner <[email protected]> wrote:

Quoted 12 lines · Jose A. Perez de Azpillaga

Add IIO driver for Broadcom APDS9999 ambient light sensor.

The APDS9999 is a digital proximity and RGB sensor with ALS capability. This driver implements the ALS/Lux functionality using the green channel, which uses optical coating technology to approximate the human eye spectral response.

Proximity (PS) and RGB color features are not yet implemented.

drivers/iio/light/apds9999.c line 46

Quoted 7 lines

drivers/iio/light/apds9999.c new file +7 -0

+enum apds9999_gain {
+	APDS9999_GAIN_1X = 0,
+	APDS9999_GAIN_3X = 1,
+	APDS9999_GAIN_6X = 2,
+	APDS9999_GAIN_9X = 3,
+	APDS9999_GAIN_18X = 4,
+};    

Giving the natural values of enum explicitly just seems like noise IMHO. I wasted time looking for an anomaly.

Quoted 5 lines

I tend to ask for this when they are hardware field values to make the point the values matter rather than just being an enum. I'm not that fussed though.

Jonathan

In that case, I would just use #define instead of enum.

Add IIO driver and DT binding for the Broadcom APDS9999 ambient light and proximity sensor. The green channel uses optical coating technology to approximate the human eye spectral response for ALS/lux measurements. IIO_INTENSITY channels are also provided for red, green, blue, and clear/IR so userspace can compute its own weighted lux.

Questions for reviewers:
1. Is the green channel as an ALS/lux approximation acceptable given the datasheet's claim of optical coating to emulate V(lambda)?

2. Is the IIO_INTENSITY channel layout correct? (red, green, blue, clear with modifiers, no scale)

3. Should the binding be merged with avago,apds9300.yaml or kept separate given the extra vled-supply?

v2:
- Added IIO_INTENSITY channels for R, G, B, clear
- Switched to guard(mutex)(), devm_mutex_init(), dev_err_probe()
- Replaced remove() with devm_add_action_or_reset()
- Don't fail probe on PART_ID mismatch (fallback compatibles)
- Replaced manual shifts with FIELD_PREP() / GENMASK
- Used get_unaligned_le24(), sizeof(buf), NSEC_PER_SEC, fsleep()
- Named gain register values, explicit resolution enum values
- Removed section comments, grouped bit defines under registers
- Squashed Kconfig/Makefile into driver patch
- Split MAINTAINERS entry across patches
- DT binding: added vled-supply, interrupts, required vdd-supply
- DT binding: fixed title, added blank lines, full description
- Dropped "DT binding" duplication from binding commit subject

Link to v1: https://lore.kernel.org/linux-iio/[email protected]/

Jose A. Perez de Azpillaga (2):
dt-bindings: iio: light: add Broadcom APDS9999
iio: light: add support for APDS9999 sensor

 .../bindings/iio/light/brcm,apds9999.yaml     |  53 +++
 MAINTAINERS                                   |   7 +
 drivers/iio/light/Kconfig                     |  10 +
 drivers/iio/light/Makefile                    |   1 +
 drivers/iio/light/apds9999.c                  | 344 ++++++++++++++++++
 5 files changed, 415 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/brcm,apds9999.yaml
 create mode 100644 drivers/iio/light/apds9999.c