[PATCH v3 0/2] Add support for AS7343 multi-spectral sensor

[PATCH v3 0/2] Add support for AS7343 multi-spectral sensor

[Chang Yu]

This series adds initial support for the AMS AS7343 14-channel
multi-spectral sensor.

The sensor has 14 optical channels (11 visible + NIR + clear +
flicker) in total. This initial driver supports reading raw counts
from all 12 spectral channels (11 visible + NIR) via sysfs and basic
power management.

Not yet supported:
- Configurable integration time and gain
- Interrupt support
- Clear (VIS) channel and flicker detection

Patch 1 adds device tree bindings.
Patch 2 adds the driver.

Testing was performed on a Raspberry Pi 4.

Datasheet: https://look.ams-osram.com/m/5f2d27fff9a874d2/original/AS7343-14-Channel-Multi-Spectral-Sensor.pdf

Changes in v3:
  - Fix gpio description and example in dt.
  - Only start measurements after suspend action has been registered.
  - Add a mutex and pm_runtime_resume_and_get before reading measurements.

Changes in v2:
  - Add the LDR, the interrupt pin, and the GPIO pin to the dt bindings.
  - Adjust the default gain to x256 and integration time to 50.1ms as
  recommended by the datasheet.
  - Use read_label instead of .extend
  - Remove all unused scan_index related constants.

Chang Yu (2):
  dt-bindings: iio: light: add as7343
  iio: light: add AS7343 multi-spectral sensor driver

 .../bindings/iio/light/ams,as7343.yaml        |  72 ++++
 MAINTAINERS                                   |   7 +
 drivers/iio/light/Kconfig                     |  11 +
 drivers/iio/light/Makefile                    |   1 +
 drivers/iio/light/as7343.c                    | 397 ++++++++++++++++++
 5 files changed, 488 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/ams,as7343.yaml
 create mode 100644 drivers/iio/light/as7343.c

-- 
2.55.0

[PATCH v3 1/2] dt-bindings: iio: light: add as7343

[Chang Yu]

Add binding for AMS AS7343 which is a 14-channel multi-spectral sensor
with i2c address of 0x39.

Datasheet: https://look.ams-osram.com/m/5f2d27fff9a874d2/original/AS7343-14-Channel-Multi-Spectral-Sensor.pdf
Signed-off-by: Chang Yu <marcus.yu.56@gmail.com>
---
Changes in v3:
 - Add missing include for gpio.
 - Expand GPIO descrption to include hardware synchronization.
 - Use led-max-microamp instead of led-current-microamp for the LDR pin.

Changes in v2:
 - Add the LDR, the interrupt pin, and the GPIO pin to the bindings.
 - Fix node name and unit address mismatch.
 - Include MAINTAINERS changes.

 .../bindings/iio/light/ams,as7343.yaml        | 72 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 78 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/ams,as7343.yaml

diff --git a/Documentation/devicetree/bindings/iio/light/ams,as7343.yaml b/Documentation/devicetree/bindings/iio/light/ams,as7343.yaml
new file mode 100644
index 000000000000..6b8a05be0043
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/light/ams,as7343.yaml
@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/light/ams,as7343.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AMS AS7343 14-Channel Multi-Spectral Sensor
+
+maintainers:
+  - Chang Yu <marcus.yu.56@gmail.com>
+
+description: |
+  The AMS AS7343 is a 14-channel multi-spectral sensor with i2c address of 0x39.
+  https://look.ams-osram.com/m/5f2d27fff9a874d2/original/AS7343-14-Channel-Multi-Spectral-Sensor.pdf
+
+properties:
+  compatible:
+    enum:
+      - ams,as7343
+
+  reg:
+    description:
+      I2C address of the device (0x39).
+    maxItems: 1
+
+  interrupts:
+    description:
+      Open drain output active low interrupt pin.
+    maxItems: 1
+
+  vdd-supply: true
+
+  ams,led-max-microamp:
+    description:
+      The driver current for the external LED connected to the LDR pin.
+    minimum: 4000
+    maximum: 258000
+    multipleOf: 2000
+    default: 12000
+
+  sync-gpios:
+    description: |
+      Optional GPIO pin that can be used either as a synchronization input to
+      start/stop measurement or as an external start/stop signal for
+      synchronizing with the connected LED.
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        multispectral-sensor@39 {
+            compatible = "ams,as7343";
+            reg = <0x39>;
+            interrupts = <7 IRQ_TYPE_LEVEL_LOW>;
+            vdd-supply = <&vdd_regulator>;
+            ams,led-max-microamp = <14000>;
+            sync-gpios = <&gpio0 6 GPIO_ACTIVE_LOW>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 04fa5322d9f7..8cf4e1635053 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1430,6 +1430,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/light/ams,as73211.yaml
 F:	drivers/iio/light/as73211.c
 
+AMS AS7343 DRIVER
+M:	Chang Yu <marcus.yu.56@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/light/ams,as7343.yaml
+
 AMT (Automatic Multicast Tunneling)
 M:	Taehee Yoo <ap420073@gmail.com>
 L:	netdev@vger.kernel.org
-- 
2.55.0

[PATCH v3 2/2] iio: light: add AS7343 multi-spectral sensor driver

[Chang Yu]

This patch adds a driver for the AMS AS7343 14-channel multi-spectral
sensor with I2C interface.

The driver exposes 12 spectral channels (11 visible + 1 near-infrared)
via the IIO sysfs interface. Each channel's raw data is provided as a
16-bit little-endian unsigned integer.

Basic power management (suspend/resume) is supported. Note that power
management is designed in such a way that we only stop spectrual
measurements when susepended and do not power off.

More complex features such as auto-suspend, interrupts, and
configurable gain/integration time will be added in future patches.

Datasheet: https://look.ams-osram.com/m/5f2d27fff9a874d2/original/AS7343-14-Channel-Multi-Spectral-Sensor.pdf
Signed-off-by: Chang Yu <marcus.yu.56@gmail.com>
---
Changes in v3:
 - Hold a mutex before reading measurements.
 - Add pm_runtime_resume_and_get before reading measurements.
 - Only start measurements after suspend action has been successfully
   registered
 - Check the return value of regmap_read when verifying device ID.

Changes in v2:
 - Adjust the default gain to x256 and integration time to 50.1ms as
 recommended by the datasheet.
 - Use read_label instead of .extend
 - Remove all unused scan_index related constants.
 - Add missing calls to pm_runtime_* methods in probe.
 - Fix various code style issues

 MAINTAINERS                |   1 +
 drivers/iio/light/Kconfig  |  11 +
 drivers/iio/light/Makefile |   1 +
 drivers/iio/light/as7343.c | 397 +++++++++++++++++++++++++++++++++++++
 4 files changed, 410 insertions(+)
 create mode 100644 drivers/iio/light/as7343.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8cf4e1635053..236102b3c28e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1435,6 +1435,7 @@ M:	Chang Yu <marcus.yu.56@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/iio/light/ams,as7343.yaml
+F:	drivers/iio/light/as7343.c
 
 AMT (Automatic Multicast Tunneling)
 M:	Taehee Yoo <ap420073@gmail.com>
diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index ef36824f312f..edbeeba9d873 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -149,6 +149,17 @@ config AS73211
 	 This driver can also be built as a module.  If so, the module
 	 will be called as73211.
 
+config AS7343
+	tristate "AMS AS7343 14-Channel Multi-Spectral Sensor"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	 Say Y here to build support for the AMS AS7343 14-channel
+	 multi-spectral sensor.
+
+	 To compile this driver as a module, choose M here: the module will
+	 be called as7343.
+
 config BH1745
 	tristate "ROHM BH1745 colour sensor"
 	depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 64e354c49ed8..5d0d33802519 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_APDS9306)		+= apds9306.o
 obj-$(CONFIG_APDS9960)		+= apds9960.o
 obj-$(CONFIG_APDS9999)		+= apds9999.o
 obj-$(CONFIG_AS73211)		+= as73211.o
+obj-$(CONFIG_AS7343)		+= as7343.o
 obj-$(CONFIG_BH1745)		+= bh1745.o
 obj-$(CONFIG_BH1750)		+= bh1750.o
 obj-$(CONFIG_BH1780)		+= bh1780.o
diff --git a/drivers/iio/light/as7343.c b/drivers/iio/light/as7343.c
new file mode 100644
index 000000000000..8982cd6ec5d8
--- /dev/null
+++ b/drivers/iio/light/as7343.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Support for AMS AS7343 14-channel multi-spectral sensor.
+ * (7-bit I2C slave address 0x39)
+ *
+ * Based on the work of:
+ *   Christian Eggers <ceggers@arri.de> (AS73211 driver)
+ *
+ * Copyright (c) 2026 Chang Yu <marcus.yu.56@gmail.com>
+ *
+ * Datasheets:
+ *   https://look.ams-osram.com/m/5f2d27fff9a874d2/original/AS7343-14-Channel-Multi-Spectral-Sensor.pdf
+ *
+ * TODO:
+ *   - Autosuspend
+ *   - Support for configurable gain and integration time
+ *   - Interrupt support
+ *   - Add support for reading the VIS channel
+ *   - Flicker detection
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+#include <asm/byteorder.h>
+
+#include <linux/iio/iio.h>
+
+/* AS7343 registers */
+#define AS7343_ID	    0x5a
+
+#define AS7343_ENABLE	    0x80
+#define AS7343_ENABLE_PON   BIT(0)
+#define AS7343_ENABLE_SP_EN BIT(1)
+
+/*
+ * Integration time is calculated as (ATIME + 1) * ((ASTEP + 1) * 2.78us).
+ * Setting a 30 * 1.67ms = 50.1ms integration test as the default for now.
+ */
+#define AS7343_ATIME			   0x81
+#define AS7343_ATIME_VAL		   29 /* (29 + 1) = 30 steps */
+#define AS7343_ASTEP			   0xd4
+#define AS7343_ASTEP_VAL		   599 /* 1.67ms step size */
+
+#define AS7343_CFG0			   0xbf
+#define AS7343_CFG0_REG_BANK		   BIT(4)
+
+#define AS7343_CFG1			   0xc6
+#define AS7343_CFG1_AGAIN		   GENMASK(4, 0)
+#define AS7343_CFG1_AGAIN_X0_5		   0
+#define AS7343_CFG1_AGAIN_X1		   1
+#define AS7343_CFG1_AGAIN_X2		   2
+#define AS7343_CFG1_AGAIN_X4		   3
+#define AS7343_CFG1_AGAIN_X8		   4
+#define AS7343_CFG1_AGAIN_X16		   5
+#define AS7343_CFG1_AGAIN_X32		   6
+#define AS7343_CFG1_AGAIN_X64		   7
+#define AS7343_CFG1_AGAIN_X128		   8
+#define AS7343_CFG1_AGAIN_X256		   9
+#define AS7343_CFG1_AGAIN_X512		   10
+#define AS7343_CFG1_AGAIN_X1024		   11
+#define AS7343_CFG1_AGAIN_X2048		   12
+
+#define AS7343_CFG20			   0xd6
+#define AS7343_CFG20_AUTO_SMUX		   GENMASK(6, 5)
+#define AS7343_CFG20_AUTO_SMUX_READOUT_ALL 3 /* all-channel readout */
+
+#define AS7343_ASTATUS			   0x94
+
+/* AS7343 data registers */
+#define AS7343_DATA_FZ	0x95
+#define AS7343_DATA_FY	0x97
+#define AS7343_DATA_FXL 0x99
+#define AS7343_DATA_NIR 0x9b
+#define AS7343_DATA_F2	0xa1
+#define AS7343_DATA_F3	0xa3
+#define AS7343_DATA_F4	0xa5
+#define AS7343_DATA_F6	0xa7
+#define AS7343_DATA_F1	0xad
+#define AS7343_DATA_F7	0xaf
+#define AS7343_DATA_F8	0xb1
+#define AS7343_DATA_F5	0xb3
+#define AS7343_MAX	0xff
+
+/* AS7343 channel indices. MUST match data register order above. */
+#define AS7343_CHAN_IDX_FZ  0
+#define AS7343_CHAN_IDX_FY  1
+#define AS7343_CHAN_IDX_FXL 2
+#define AS7343_CHAN_IDX_NIR 3
+#define AS7343_CHAN_IDX_F2  4
+#define AS7343_CHAN_IDX_F3  5
+#define AS7343_CHAN_IDX_F4  6
+#define AS7343_CHAN_IDX_F6  7
+#define AS7343_CHAN_IDX_F1  8
+#define AS7343_CHAN_IDX_F7  9
+#define AS7343_CHAN_IDX_F8  10
+#define AS7343_CHAN_IDX_F5  11
+
+#define AS7343_CHAN(_chan)                                    \
+	{                                                     \
+		.type = IIO_INTENSITY,                        \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+		.address = AS7343_DATA_##_chan,               \
+		.indexed = 1,                                 \
+		.channel = AS7343_CHAN_IDX_##_chan,           \
+	}
+
+static const struct iio_chan_spec as7343_channels[] = {
+	AS7343_CHAN(FZ), AS7343_CHAN(FY), AS7343_CHAN(FXL), AS7343_CHAN(NIR),
+	AS7343_CHAN(F2), AS7343_CHAN(F3), AS7343_CHAN(F4),  AS7343_CHAN(F6),
+	AS7343_CHAN(F1), AS7343_CHAN(F7), AS7343_CHAN(F8),  AS7343_CHAN(F5),
+};
+
+struct as7343_data {
+	struct regmap *regmap;
+	struct mutex mutex;
+};
+
+static int as7343_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan, int *val,
+			   int *val2, long mask)
+{
+	struct as7343_data *data = iio_priv(indio_dev);
+	struct device *dev = regmap_get_device(data->regmap);
+	int ret;
+	unsigned int unused;
+	__le16 result;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW: {
+		/* Wait until integration time passes for all 3 cycles. */
+		msleep(160);
+
+		/*
+		 * Reading ASTATUS latches all data registers to this read.
+		 * We don't care about the returned saturation/gain status for
+		 * now.
+		 */
+		guard(mutex)(&data->mutex);
+		ret = regmap_read(data->regmap, AS7343_ASTATUS, &unused);
+		if (ret)
+			break;
+
+		ret = regmap_bulk_read(data->regmap, chan->address, &result, 2);
+		if (ret)
+			break;
+
+		*val = le16_to_cpu(result);
+		ret = IIO_VAL_INT;
+		break;
+	}
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	pm_runtime_put(dev);
+	return ret;
+}
+
+static const char *as7343_channel_label(struct iio_chan_spec const *chan)
+{
+	switch (chan->channel) {
+	case AS7343_CHAN_IDX_FZ:
+		return "FZ";
+	case AS7343_CHAN_IDX_FY:
+		return "FY";
+	case AS7343_CHAN_IDX_FXL:
+		return "FXL";
+	case AS7343_CHAN_IDX_NIR:
+		return "NIR";
+	case AS7343_CHAN_IDX_F2:
+		return "F2";
+	case AS7343_CHAN_IDX_F3:
+		return "F3";
+	case AS7343_CHAN_IDX_F4:
+		return "F4";
+	case AS7343_CHAN_IDX_F6:
+		return "F6";
+	case AS7343_CHAN_IDX_F1:
+		return "F1";
+	case AS7343_CHAN_IDX_F7:
+		return "F7";
+	case AS7343_CHAN_IDX_F8:
+		return "F8";
+	case AS7343_CHAN_IDX_F5:
+		return "F5";
+	default:
+		return NULL;
+	}
+}
+
+static int as7343_read_label(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, char *label)
+{
+	const char *name;
+
+	name = as7343_channel_label(chan);
+	if (!name)
+		return -EINVAL;
+
+	return sysfs_emit(label, "%s\n", name);
+}
+
+static const struct iio_info as7343_info = {
+	.read_raw = as7343_read_raw,
+	.read_label = as7343_read_label,
+};
+
+static const struct regmap_config as7343_regmap_config = {
+	.name = "as7343",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = AS7343_MAX,
+	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+	.cache_type = REGCACHE_NONE,
+};
+
+static int as7343_setup_device(struct device *dev, struct as7343_data *data)
+{
+	unsigned int val;
+	__le16 step;
+	int ret;
+
+	/* Power on */
+	ret = regmap_set_bits(data->regmap, AS7343_ENABLE, AS7343_ENABLE_PON);
+	if (ret)
+		return ret;
+
+	/* Need to set REG_BANK to 1 before we can access ID */
+	ret = regmap_set_bits(data->regmap, AS7343_CFG0, AS7343_CFG0_REG_BANK);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(data->regmap, AS7343_ID, &val);
+	if (ret)
+		return ret;
+
+	if (val != 0x81)
+		dev_info(dev, "Unknown device ID: %x\n", val);
+
+	ret = regmap_clear_bits(data->regmap, AS7343_CFG0,
+				AS7343_CFG0_REG_BANK);
+	if (ret)
+		return ret;
+
+	/* Configure the SMUX to readout all channels */
+	ret = regmap_update_bits(
+		data->regmap, AS7343_CFG20, AS7343_CFG20_AUTO_SMUX,
+		FIELD_PREP(AS7343_CFG20_AUTO_SMUX,
+			   AS7343_CFG20_AUTO_SMUX_READOUT_ALL));
+	if (ret)
+		return ret;
+
+	/* Set 50.1ms integration time and x256 gain for now */
+	step = cpu_to_le16(AS7343_ASTEP_VAL);
+	ret = regmap_bulk_write(data->regmap, AS7343_ASTEP, &step, 2);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, AS7343_ATIME, AS7343_ATIME_VAL);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(data->regmap, AS7343_CFG1, AS7343_CFG1_AGAIN,
+				  FIELD_PREP(AS7343_CFG1_AGAIN,
+					     AS7343_CFG1_AGAIN_X256));
+}
+
+static int as7343_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct as7343_data *data = iio_priv(indio_dev);
+
+	return regmap_clear_bits(data->regmap, AS7343_ENABLE,
+				 AS7343_ENABLE_SP_EN);
+}
+
+static int as7343_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct as7343_data *data = iio_priv(indio_dev);
+
+	return regmap_set_bits(data->regmap, AS7343_ENABLE,
+			       AS7343_ENABLE_SP_EN);
+}
+
+static void as7343_suspend_action(void *data)
+{
+	as7343_suspend(data);
+}
+
+static int as7343_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct as7343_data *data;
+	struct iio_dev *indio_dev;
+	struct regmap *regmap;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	regmap = devm_regmap_init_i2c(client, &as7343_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->regmap = regmap;
+	mutex_init(&data->mutex);
+
+	indio_dev->name = "as7343";
+	indio_dev->info = &as7343_info;
+	indio_dev->channels = as7343_channels;
+	indio_dev->num_channels = ARRAY_SIZE(as7343_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = devm_regulator_get_enable(dev, "vdd");
+	if (ret)
+		return ret;
+
+	ret = as7343_setup_device(dev, data);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, as7343_suspend_action, dev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to add suspend action\n");
+
+	ret = pm_runtime_set_active(dev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to activate PM runtime\n");
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable PM runtime\n");
+
+	/* Start measurements */
+	ret = regmap_set_bits(data->regmap, AS7343_ENABLE, AS7343_ENABLE_SP_EN);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(as7343_pm_ops, as7343_suspend, as7343_resume,
+				 NULL);
+
+static const struct of_device_id as7343_of_match[] = {
+	{ .compatible = "ams,as7343" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, as7343_of_match);
+
+static const struct i2c_device_id as7343_id[] = {
+	{ .name = "as7343" },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, as7343_id);
+
+static struct i2c_driver as7343_driver = {
+	.driver = {
+		.name           = "as7343",
+		.of_match_table = as7343_of_match,
+		.pm             = pm_ptr(&as7343_pm_ops),
+	},
+	.probe      = as7343_probe,
+	.id_table   = as7343_id,
+};
+module_i2c_driver(as7343_driver);
+
+MODULE_AUTHOR("Chang Yu <marcus.yu.56@gmail.com>");
+MODULE_DESCRIPTION("AS7343 14 Channel Multi-Spectral Sensor driver");
+MODULE_LICENSE("GPL");
-- 
2.55.0

Re: [PATCH v3 2/2] iio: light: add AS7343 multi-spectral sensor driver

[Andy Shevchenko]

On Wed, Sep 09, 2026 at 11:38:13PM -0700, Chang Yu wrote:
> This patch adds a driver for the AMS AS7343 14-channel multi-spectral
> sensor with I2C interface.
> 
> The driver exposes 12 spectral channels (11 visible + 1 near-infrared)
> via the IIO sysfs interface. Each channel's raw data is provided as a
> 16-bit little-endian unsigned integer.
> 
> Basic power management (suspend/resume) is supported. Note that power
> management is designed in such a way that we only stop spectrual
> measurements when susepended and do not power off.
> 
> More complex features such as auto-suspend, interrupts, and
> configurable gain/integration time will be added in future patches.

It's v3 already. Can you browse the linux-iio@ mailing list archive and see
what are the common comments on the new contributions? I think you may ask
AI to help with the summary. This patch has tons of what has been repeated
over and over...

...

> +#include <linux/array_size.h>
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/cleanup.h>
> +#include <linux/dev_printk.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>

> +#include <linux/pm.h>

This is implied by pm_runtime.h IIRC.

> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/sysfs.h>
> +#include <linux/types.h>

...

> +/* AS7343 registers */
> +#define AS7343_ID	    0x5a
> +
> +#define AS7343_ENABLE	    0x80

Make sure the indentation of the definition of the same kind are the same.

...

> +/*
> + * Integration time is calculated as (ATIME + 1) * ((ASTEP + 1) * 2.78us).
> + * Setting a 30 * 1.67ms = 50.1ms integration test as the default for now.
> + */
> +#define AS7343_ATIME			   0x81

I believe this one is related to the register offsets? (see above why)

...

> +static int as7343_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan, int *val,
> +			   int *val2, long mask)

Please, split logically.

			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)

> +{
> +	struct as7343_data *data = iio_priv(indio_dev);
> +	struct device *dev = regmap_get_device(data->regmap);
> +	int ret;
> +	unsigned int unused;
> +	__le16 result;

Preserve reversed xmas tree order.

> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret)
> +		return ret;

Use PM_RUNTIME_ACQUIRE*().

> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW: {
> +		/* Wait until integration time passes for all 3 cycles. */
> +		msleep(160);
> +
> +		/*
> +		 * Reading ASTATUS latches all data registers to this read.
> +		 * We don't care about the returned saturation/gain status for
> +		 * now.
> +		 */
> +		guard(mutex)(&data->mutex);
> +		ret = regmap_read(data->regmap, AS7343_ASTATUS, &unused);
> +		if (ret)
> +			break;
> +
> +		ret = regmap_bulk_read(data->regmap, chan->address, &result, 2);

sizeof()

> +		if (ret)
> +			break;
> +
> +		*val = le16_to_cpu(result);
> +		ret = IIO_VAL_INT;
> +		break;
> +	}
> +
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	pm_runtime_put(dev);
> +	return ret;
> +}

(All comments for the above function is what has been repeated in many
 contributions for sure.)

 ...

> +static const char *as7343_channel_label(struct iio_chan_spec const *chan)
> +{
> +	switch (chan->channel) {
> +	case AS7343_CHAN_IDX_FZ:
> +		return "FZ";
> +	case AS7343_CHAN_IDX_FY:
> +		return "FY";
> +	case AS7343_CHAN_IDX_FXL:
> +		return "FXL";
> +	case AS7343_CHAN_IDX_NIR:
> +		return "NIR";
> +	case AS7343_CHAN_IDX_F2:
> +		return "F2";
> +	case AS7343_CHAN_IDX_F3:
> +		return "F3";
> +	case AS7343_CHAN_IDX_F4:
> +		return "F4";
> +	case AS7343_CHAN_IDX_F6:
> +		return "F6";
> +	case AS7343_CHAN_IDX_F1:
> +		return "F1";
> +	case AS7343_CHAN_IDX_F7:
> +		return "F7";
> +	case AS7343_CHAN_IDX_F8:
> +		return "F8";
> +	case AS7343_CHAN_IDX_F5:
> +		return "F5";
> +	default:
> +		return NULL;
> +	}

Why not keeping this in a static array?

> +}
> +
> +static int as7343_read_label(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan, char *label)
> +{
> +	const char *name;
> +
> +	name = as7343_channel_label(chan);
> +	if (!name)
> +		return -EINVAL;

Why? Can't it be taken from DT?

> +	return sysfs_emit(label, "%s\n", name);
> +}

...

> +static const struct regmap_config as7343_regmap_config = {
> +	.name = "as7343",
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = AS7343_MAX,
> +	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
> +	.val_format_endian = REGMAP_ENDIAN_LITTLE,

> +	.cache_type = REGCACHE_NONE,

Why?! This needs a very good justification.

> +};

...

> +static int as7343_setup_device(struct device *dev, struct as7343_data *data)
> +{

	struct regmap *map = data->regmap;

will help to reduce verbosity of the below, and might even save some LoC...

> +	unsigned int val;
> +	__le16 step;
> +	int ret;
> +
> +	/* Power on */
> +	ret = regmap_set_bits(data->regmap, AS7343_ENABLE, AS7343_ENABLE_PON);
> +	if (ret)
> +		return ret;
> +
> +	/* Need to set REG_BANK to 1 before we can access ID */
> +	ret = regmap_set_bits(data->regmap, AS7343_CFG0, AS7343_CFG0_REG_BANK);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(data->regmap, AS7343_ID, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val != 0x81)
> +		dev_info(dev, "Unknown device ID: %x\n", val);
> +
> +	ret = regmap_clear_bits(data->regmap, AS7343_CFG0,
> +				AS7343_CFG0_REG_BANK);

...for example, here:

	ret = regmap_clear_bits(map, AS7343_CFG0, AS7343_CFG0_REG_BANK);

> +	if (ret)
> +		return ret;
> +
> +	/* Configure the SMUX to readout all channels */

> +	ret = regmap_update_bits(

Huh?! Please, check the formatting and indentation style.

> +		data->regmap, AS7343_CFG20, AS7343_CFG20_AUTO_SMUX,
> +		FIELD_PREP(AS7343_CFG20_AUTO_SMUX,
> +			   AS7343_CFG20_AUTO_SMUX_READOUT_ALL));
> +	if (ret)
> +		return ret;
> +
> +	/* Set 50.1ms integration time and x256 gain for now */
> +	step = cpu_to_le16(AS7343_ASTEP_VAL);
> +	ret = regmap_bulk_write(data->regmap, AS7343_ASTEP, &step, 2);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(data->regmap, AS7343_ATIME, AS7343_ATIME_VAL);
> +	if (ret)
> +		return ret;
> +
> +	return regmap_update_bits(data->regmap, AS7343_CFG1, AS7343_CFG1_AGAIN,
> +				  FIELD_PREP(AS7343_CFG1_AGAIN,
> +					     AS7343_CFG1_AGAIN_X256));
> +}

...

> +static int as7343_suspend(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct as7343_data *data = iio_priv(indio_dev);
> +
> +	return regmap_clear_bits(data->regmap, AS7343_ENABLE,
> +				 AS7343_ENABLE_SP_EN);
> +}
> +
> +static int as7343_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct as7343_data *data = iio_priv(indio_dev);
> +
> +	return regmap_set_bits(data->regmap, AS7343_ENABLE,
> +			       AS7343_ENABLE_SP_EN);
> +}

Same, use temporary for struct regmap.

...

> +static int as7343_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct as7343_data *data;
> +	struct iio_dev *indio_dev;
> +	struct regmap *regmap;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	regmap = devm_regmap_init_i2c(client, &as7343_regmap_config);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	data->regmap = regmap;

> +	mutex_init(&data->mutex);

devm_mutex_init().

> +
> +	indio_dev->name = "as7343";
> +	indio_dev->info = &as7343_info;
> +	indio_dev->channels = as7343_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(as7343_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = devm_regulator_get_enable(dev, "vdd");
> +	if (ret)
> +		return ret;
> +
> +	ret = as7343_setup_device(dev, data);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_add_action_or_reset(dev, as7343_suspend_action, dev);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "Failed to add suspend action\n");
> +
> +	ret = pm_runtime_set_active(dev);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "Failed to activate PM runtime\n");
> +
> +	ret = devm_pm_runtime_enable(dev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to enable PM runtime\n");
> +
> +	/* Start measurements */
> +	ret = regmap_set_bits(data->regmap, AS7343_ENABLE, AS7343_ENABLE_SP_EN);
> +	if (ret)
> +		return ret;
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}

...

> +static DEFINE_RUNTIME_DEV_PM_OPS(as7343_pm_ops, as7343_suspend, as7343_resume,
> +				 NULL);

Again, split logically. Options are:

static DEFINE_RUNTIME_DEV_PM_OPS(as7343_pm_ops, as7343_suspend, as7343_resume, NULL);

static DEFINE_RUNTIME_DEV_PM_OPS(as7343_pm_ops,
				 as7343_suspend, as7343_resume, NULL);

static DEFINE_RUNTIME_DEV_PM_OPS(as7343_pm_ops,
				 as7343_suspend,
				 as7343_resume,
				 NULL);

(I personally prefer compromise as depicted in the second example).

...

> +static const struct of_device_id as7343_of_match[] = {
> +	{ .compatible = "ams,as7343" },
> +	{ },

No comma in the terminator entry.

> +};
> +MODULE_DEVICE_TABLE(of, as7343_of_match);
> +
> +static const struct i2c_device_id as7343_id[] = {
> +	{ .name = "as7343" },
> +	{ },

Ditto.

> +};
> +MODULE_DEVICE_TABLE(i2c, as7343_id);

...

> +static struct i2c_driver as7343_driver = {
> +	.driver = {
> +		.name           = "as7343",
> +		.of_match_table = as7343_of_match,
> +		.pm             = pm_ptr(&as7343_pm_ops),
> +	},
> +	.probe      = as7343_probe,
> +	.id_table   = as7343_id,

Indentation of the assignees with tabs makes it harder to maintain (in case
more lines got added it might require to reindent all of them).

> +};
> +module_i2c_driver(as7343_driver);

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 2/2] iio: light: add AS7343 multi-spectral sensor driver

[Chang Yu]

Hi Andy

Thanks for the thorough review. Just one quick clarification inline.

On Thu, Sep 10, 2026 at 12:07:42PM +0300, Andy Shevchenko wrote:
> On Wed, Sep 09, 2026 at 11:38:13PM -0700, Chang Yu wrote:
> 
> ...
> 
> > +}
> > +
> > +static int as7343_read_label(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan, char *label)
> > +{
> > +	const char *name;
> > +
> > +	name = as7343_channel_label(chan);
> > +	if (!name)
> > +		return -EINVAL;
> 
> Why? Can't it be taken from DT?
> 

These channel labels correspond to the physical optical channel
names defined by the datasheet. Each name corresponds to a
pre-defined range of wavelengths. They are fixed internal properties
of the chip, so IMO hardcoding them in the driver is more
approriate.

> > +	return sysfs_emit(label, "%s\n", name);
> > +}
> 
> ...
> 

Best,
Chang

Re: [PATCH v3 2/2] iio: light: add AS7343 multi-spectral sensor driver

[Andy Shevchenko]

On Thu, Sep 10, 2026 at 12:22:01PM -0700, Chang Yu wrote:
> On Thu, Sep 10, 2026 at 12:07:42PM +0300, Andy Shevchenko wrote:
> > On Wed, Sep 09, 2026 at 11:38:13PM -0700, Chang Yu wrote:

...

> > > +	name = as7343_channel_label(chan);
> > > +	if (!name)
> > > +		return -EINVAL;
> > 
> > Why? Can't it be taken from DT?
> 
> These channel labels correspond to the physical optical channel
> names defined by the datasheet. Each name corresponds to a
> pre-defined range of wavelengths. They are fixed internal properties
> of the chip, so IMO hardcoding them in the driver is more
> approriate.

Please, make a comment on top of the string array, with probably citing the
datasheet table with the wavelength ranges.

/*
 * Channel names as defined in the datasheet:
 * // hypothetical example // ... - 200-300 nm
 * ...
 */
static const char * const ..._names[] = {
	...names...
};

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 1/2] dt-bindings: iio: light: add as7343

[Krzysztof Kozlowski]

On Wed, Sep 09, 2026 at 11:38:12PM -0700, Chang Yu wrote:
> Add binding for AMS AS7343 which is a 14-channel multi-spectral sensor
> with i2c address of 0x39.
> 
> Datasheet: https://look.ams-osram.com/m/5f2d27fff9a874d2/original/AS7343-14-Channel-Multi-Spectral-Sensor.pdf
> Signed-off-by: Chang Yu <marcus.yu.56@gmail.com>
> ---
> Changes in v3:
>  - Add missing include for gpio.
>  - Expand GPIO descrption to include hardware synchronization.
>  - Use led-max-microamp instead of led-current-microamp for the LDR pin.
> 
> Changes in v2:
>  - Add the LDR, the interrupt pin, and the GPIO pin to the bindings.
>  - Fix node name and unit address mismatch.
>  - Include MAINTAINERS changes.
> 

You need to address Sashiko review.

Best regards,
Krzysztof