[PATCH v4 0/2] Support for Osram as3668 LED driver

[PATCH v4 0/2] Support for Osram as3668 LED driver

[Lukas Timmermann]

This patch adds basic support for the as3668 driver IC via I2C interface. 
The IC is capable of driving four individual LEDs up to 25.5mA per 
channel. Hardware blinking would be theoretically possible, but this chip
only supports a few set on/off-delays which makes using that feature 
unfeasable, therefore my driver doesn't offer that capability. 
It's intended applications is in mobile devices such as phones, 
tablets and cameras. This driver was tested and is working on 
a samsung-manta which is running postmarketOS with a near mainline kernel.

Please note: This is my first suggested patch to the kernel. 
checkpatch.pl runs without warnings or errors. 
I've read the docs in regards to the led subsystem, 
coding style and submission of patches, 
but I'm still a bit unsure about the general workflow. 

I will try my best.

Changes in v4:
- Fixed some mistakes made in the dt file pointed out in v3.
- Swapped dt and driver in patch series. DT now comes first.
- Fixed errors in Kconfig due to last minute changes.
- Added dt file into MAINTAINERS file.
- Link to v3: https://lore.kernel.org/lkml/20250604225838.102910-2-linux@timmermann.space/
Changes in v3:
- Fixed an extra whitespace in the dt bindings documentation.
- Sent patch to all related lists and maintainers.
- Link to v2: https://lore.kernel.org/lkml/20250531120715.302870-4-linux@timmermann.space/
Changes in v2:
- Fixed reading led subnodes in dt incorrectly, 
  which caused wrong numbering and a segfault when removing the driver module
- Fixed calling of_property_read_u8 with an int, causing a compiler error
- Added more error checking during writes to the i2c bus
- Link to v1: https://lore.kernel.org/linux-leds/20250530184219.78085-3-linux@timmermann.space/

Signed-off-by: Lukas Timmermann <linux@timmermann.space>

Lukas Timmermann (2):
  dt-bindings: leds: Add new as3668 support
  leds: as3668: Driver for the ams Osram 4-channel i2c LED driver

 .../devicetree/bindings/leds/ams,as3668.yaml  |  74 +++++++
 MAINTAINERS                                   |   7 +
 drivers/leds/Kconfig                          |  13 ++
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-as3668.c                    | 196 ++++++++++++++++++
 5 files changed, 291 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/ams,as3668.yaml
 create mode 100644 drivers/leds/leds-as3668.c

-- 
2.49.0

[PATCH v4 1/2] dt-bindings: leds: Add new as3668 support

[Lukas Timmermann]

This patch documents the device tree bindings for
the OSRAM AS3668 LED driver. Note that the bindings
are not entirely complete, as the GPIO/Audio Input pin
is undocumented. The hardware used for testing this patch series
does not allow modification, so this pin has been omitted.

Signed-off-by: Lukas Timmermann <linux@timmermann.space>
---
 .../devicetree/bindings/leds/ams,as3668.yaml  | 74 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 80 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/ams,as3668.yaml

diff --git a/Documentation/devicetree/bindings/leds/ams,as3668.yaml b/Documentation/devicetree/bindings/leds/ams,as3668.yaml
new file mode 100644
index 000000000000..d1d73782da55
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/ams,as3668.yaml
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/ams,as3668.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Osram 4-channel i2c LED driver
+
+maintainers:
+  - Lukas Timmermann <linux@timmermann.space>
+
+description:
+  This IC can drive up to four separate LEDs.
+  Having four channels suggests it could be used with a single RGBW LED.
+
+properties:
+  compatible:
+    const: ams,as3668
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^led@[0-3]$":
+    type: object
+    $ref: common.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      reg:
+        maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      led-controller@42 {
+        compatible = "ams,as3668";
+        reg = <0x42>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led@0 {
+          reg = <0x0>;
+          function = LED_FUNCTION_STATUS;
+          color = <LED_COLOR_ID_RED>;
+        };
+
+        led@1 {
+          reg = <0x1>;
+          function = LED_FUNCTION_STATUS;
+          color = <LED_COLOR_ID_GREEN>;
+        };
+      };
+    };
+
diff --git a/MAINTAINERS b/MAINTAINERS
index c59316109e3f..091206c54c63 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3506,6 +3506,12 @@ L:	linux-leds@vger.kernel.org
 S:	Maintained
 F:	drivers/leds/flash/leds-as3645a.c
 
+AS3668 LED DRIVER
+M:	Lukas Timmermann <linux@timmermann.space>
+L:	linux-leds@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/ams,as3668.yaml
+
 ASAHI KASEI AK7375 LENS VOICE COIL DRIVER
 M:	Tianshu Qiu <tian.shu.qiu@intel.com>
 L:	linux-media@vger.kernel.org
-- 
2.49.0

[PATCH v4 2/2] leds: as3668: Driver for the ams Osram 4-channel i2c LED driver

[Lukas Timmermann]

Since there were no existing drivers for the AS3668 or related devices,
a new driver was introduced in a separate file. Similar devices were
reviewed, but none shared enough characteristics to justify code reuse.
As a result, this driver is written specifically for the AS3668.

Signed-off-by: Lukas Timmermann <linux@timmermann.space>
---
 MAINTAINERS                |   1 +
 drivers/leds/Kconfig       |  13 +++
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-as3668.c | 196 +++++++++++++++++++++++++++++++++++++
 4 files changed, 211 insertions(+)
 create mode 100644 drivers/leds/leds-as3668.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 091206c54c63..945d78fef380 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3511,6 +3511,7 @@ M:	Lukas Timmermann <linux@timmermann.space>
 L:	linux-leds@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/leds/ams,as3668.yaml
+F:	drivers/leds/leds-as3668.c
 
 ASAHI KASEI AK7375 LENS VOICE COIL DRIVER
 M:	Tianshu Qiu <tian.shu.qiu@intel.com>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a104cbb0a001..8cfb423ddf82 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -100,6 +100,19 @@ config LEDS_ARIEL
 
 	  Say Y to if your machine is a Dell Wyse 3020 thin client.
 
+config LEDS_AS3668
+	tristate "LED support for AMS AS3668"
+	depends on LEDS_CLASS
+	depends on I2C
+	help
+	  This option enables support for the AMS AS3668 LED controller.
+	  The AS3668 provides up to four LED channels and is controlled via
+	  the I2C bus. This driver offers basic brightness control for each
+	  channel, without support for blinking or other advanced features.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-as3668.
+
 config LEDS_AW200XX
 	tristate "LED support for Awinic AW20036/AW20054/AW20072/AW20108"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 2f170d69dcbf..983811384fec 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_LEDS_ADP5520)		+= leds-adp5520.o
 obj-$(CONFIG_LEDS_AN30259A)		+= leds-an30259a.o
 obj-$(CONFIG_LEDS_APU)			+= leds-apu.o
 obj-$(CONFIG_LEDS_ARIEL)		+= leds-ariel.o
+obj-$(CONFIG_LEDS_AS3668)		+= leds-as3668.o
 obj-$(CONFIG_LEDS_AW200XX)		+= leds-aw200xx.o
 obj-$(CONFIG_LEDS_AW2013)		+= leds-aw2013.o
 obj-$(CONFIG_LEDS_BCM6328)		+= leds-bcm6328.o
diff --git a/drivers/leds/leds-as3668.c b/drivers/leds/leds-as3668.c
new file mode 100644
index 000000000000..e3f90078f6ec
--- /dev/null
+++ b/drivers/leds/leds-as3668.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Osram AMS AS3668 LED Driver IC
+ *
+ *  Copyright (C) 2025 Lukas Timmermann <linux@timmermann.space>
+ */
+
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/uleds.h>
+
+#define AS3668_MAX_LEDS 4
+
+/* Chip Registers */
+#define AS3668_CHIP_ID1 0x3e
+#define AS3668_CHIP_ID2 0x3f
+
+#define AS3668_CHIP_ID2_SERIAL_MASK GENMASK(7, 4)
+#define AS3668_CHIP_ID2_REV_MASK GENMASK(3, 0)
+
+#define AS3668_CURRX_CONTROL 0x01
+#define AS3668_CURR1 0x02
+#define AS3668_CURR2 0x03
+#define AS3668_CURR3 0x04
+#define AS3668_CURR4 0x05
+
+/* Constants */
+#define AS3668_CHIP_IDENT 0xa5
+#define AS3668_CHIP_REV1 0x01
+
+struct as3668_led {
+	struct led_classdev cdev;
+	struct as3668 *chip;
+	struct fwnode_handle *fwnode;
+
+	int num;
+};
+
+struct as3668 {
+	struct i2c_client *client;
+	struct as3668_led leds[AS3668_MAX_LEDS];
+};
+
+static int as3668_read_value(struct i2c_client *client, u8 reg)
+{
+	return i2c_smbus_read_byte_data(client, reg);
+}
+
+static int as3668_write_value(struct i2c_client *client, u8 reg, u8 value)
+{
+	int err = i2c_smbus_write_byte_data(client, reg, value);
+
+	if (err)
+		dev_err(&client->dev, "error writing to reg 0x%tx, returned %d", reg, err);
+
+	return err;
+}
+
+static enum led_brightness as3668_brightness_get(struct led_classdev *cdev)
+{
+	struct as3668_led *led = container_of(cdev, struct as3668_led, cdev);
+
+	return as3668_read_value(led->chip->client, AS3668_CURR1 + led->num);
+}
+
+static void as3668_brightness_set(struct led_classdev *cdev, enum led_brightness brightness)
+{
+	struct as3668_led *led = container_of(cdev, struct as3668_led, cdev);
+
+	as3668_write_value(led->chip->client, AS3668_CURR1 + led->num, brightness);
+}
+
+static int as3668_dt_init(struct as3668 *as3668)
+{
+	struct device *dev = &as3668->client->dev;
+	struct as3668_led *led;
+	struct led_init_data init_data = {};
+	int err;
+	u32 reg;
+	int i = 0;
+
+	for_each_available_child_of_node_scoped(dev_of_node(dev), child) {
+		err = of_property_read_u32(child, "reg", &reg);
+		if (err)
+			dev_err(dev, "unable to read device tree led reg, err %d", err);
+
+		i = reg;
+
+		if (i < 0 || i > AS3668_MAX_LEDS) {
+			dev_err(dev, "unsupported led reg %d\n", i);
+			return -EOPNOTSUPP;
+		}
+
+		led = &as3668->leds[i];
+		led->fwnode = of_fwnode_handle(child);
+
+		led->num = i;
+		led->chip = as3668;
+
+		led->cdev.max_brightness = U8_MAX;
+		led->cdev.brightness_get = as3668_brightness_get;
+		led->cdev.brightness_set = as3668_brightness_set;
+
+		init_data.fwnode = led->fwnode;
+		init_data.default_label = ":";
+
+		err = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
+		if (err) {
+			dev_err(dev, "failed to register %d LED\n", i);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int as3668_probe(struct i2c_client *client)
+{
+	u8 chip_id1, chip_id2, chip_serial, chip_rev;
+	struct as3668 *as3668;
+
+	/* Check for sensible i2c address */
+	if (client->addr != 0x42)
+		return dev_err_probe(&client->dev, -EFAULT,
+				     "unexpected address for as3668 device\n");
+
+	/* Read identifier from chip */
+	chip_id1 = as3668_read_value(client, AS3668_CHIP_ID1);
+
+	if (chip_id1 != AS3668_CHIP_IDENT)
+		return dev_err_probe(&client->dev, -ENODEV,
+				"chip reported wrong id: 0x%tx\n", chip_id1);
+
+	/* Check the revision*/
+	chip_id2 = as3668_read_value(client, AS3668_CHIP_ID2);
+	chip_serial = FIELD_GET(AS3668_CHIP_ID2_SERIAL_MASK, chip_id2);
+	chip_rev = FIELD_GET(AS3668_CHIP_ID2_REV_MASK, chip_id2);
+
+	if (chip_rev != AS3668_CHIP_REV1)
+		dev_warn(&client->dev, "unexpected chip revision\n");
+
+	/* Print out information about the chip */
+	dev_dbg(&client->dev,
+		"chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
+		chip_id1, chip_id2, chip_serial, chip_rev);
+
+	as3668 = devm_kzalloc(&client->dev, struct_size(as3668, leds, AS3668_MAX_LEDS), GFP_KERNEL);
+	as3668->client = client;
+
+	as3668_dt_init(as3668);
+
+	/* Initialize the chip */
+	as3668_write_value(client, AS3668_CURRX_CONTROL, 0x55);
+	as3668_write_value(client, AS3668_CURR1, 0x00);
+	as3668_write_value(client, AS3668_CURR2, 0x00);
+	as3668_write_value(client, AS3668_CURR3, 0x00);
+	as3668_write_value(client, AS3668_CURR4, 0x00);
+
+	return 0;
+}
+
+static void as3668_remove(struct i2c_client *client)
+{
+	as3668_write_value(client, AS3668_CURRX_CONTROL, 0x0);
+}
+
+static const struct i2c_device_id as3668_idtable[] = {
+	{"as3668"},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, as3668_idtable);
+
+static const struct of_device_id as3668_match_table[] = {
+	{.compatible = "ams,as3668"},
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, as3668_match_table);
+
+static struct i2c_driver as3668_driver = {
+	.driver = {
+		.name           = "leds_as3668",
+		.of_match_table = as3668_match_table,
+	},
+	.probe          = as3668_probe,
+	.remove         = as3668_remove,
+	.id_table       = as3668_idtable,
+};
+
+module_i2c_driver(as3668_driver);
+
+MODULE_AUTHOR("Lukas Timmermann <linux@timmermann.space>");
+MODULE_DESCRIPTION("AS3668 LED driver");
+MODULE_LICENSE("GPL");
-- 
2.49.0

Re: [PATCH v4 2/2] leds: as3668: Driver for the ams Osram 4-channel i2c LED driver

[kernel test robot]

Hi Lukas,

kernel test robot noticed the following build warnings:

[auto build test WARNING on lee-leds/for-leds-next]
[also build test WARNING on linus/master v6.15 next-20250606]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Lukas-Timmermann/dt-bindings-leds-Add-new-as3668-support/20250608-055330
base:   https://git.kernel.org/pub/scm/linux/kernel/git/lee/leds.git for-leds-next
patch link:    https://lore.kernel.org/r/20250607215049.29259-3-linux%40timmermann.space
patch subject: [PATCH v4 2/2] leds: as3668: Driver for the ams Osram 4-channel i2c LED driver
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20250608/202506081650.eFkFkBP7-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250608/202506081650.eFkFkBP7-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506081650.eFkFkBP7-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/device.h:15,
                    from include/linux/acpi.h:14,
                    from include/linux/i2c.h:13,
                    from drivers/leds/leds-as3668.c:8:
   drivers/leds/leds-as3668.c: In function 'as3668_write_value':
>> drivers/leds/leds-as3668.c:55:39: warning: format '%tx' expects argument of type 'unsigned ptrdiff_t', but argument 3 has type 'int' [-Wformat=]
      55 |                 dev_err(&client->dev, "error writing to reg 0x%tx, returned %d", reg, err);
         |                                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/dev_printk.h:110:30: note: in definition of macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ^~~
   include/linux/dev_printk.h:154:56: note: in expansion of macro 'dev_fmt'
     154 |         dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                        ^~~~~~~
   drivers/leds/leds-as3668.c:55:17: note: in expansion of macro 'dev_err'
      55 |                 dev_err(&client->dev, "error writing to reg 0x%tx, returned %d", reg, err);
         |                 ^~~~~~~
   drivers/leds/leds-as3668.c:55:65: note: format string is defined here
      55 |                 dev_err(&client->dev, "error writing to reg 0x%tx, returned %d", reg, err);
         |                                                               ~~^
         |                                                                 |
         |                                                                 long unsigned int
         |                                                               %x
   drivers/leds/leds-as3668.c: In function 'as3668_probe':
   drivers/leds/leds-as3668.c:133:62: warning: format '%tx' expects argument of type 'unsigned ptrdiff_t', but argument 4 has type 'int' [-Wformat=]
     133 |                                 "chip reported wrong id: 0x%tx\n", chip_id1);
         |                                                            ~~^     ~~~~~~~~
         |                                                              |     |
         |                                                              |     int
         |                                                              long unsigned int
         |                                                            %x
   drivers/leds/leds-as3668.c:137:23: error: implicit declaration of function 'FIELD_GET' [-Wimplicit-function-declaration]
     137 |         chip_serial = FIELD_GET(AS3668_CHIP_ID2_SERIAL_MASK, chip_id2);
         |                       ^~~~~~~~~
   In file included from include/linux/printk.h:616,
                    from include/asm-generic/bug.h:22,
                    from arch/alpha/include/asm/bug.h:23,
                    from include/linux/bug.h:5,
                    from include/linux/thread_info.h:13,
                    from include/asm-generic/preempt.h:5,
                    from ./arch/alpha/include/generated/asm/preempt.h:1,
                    from include/linux/preempt.h:79,
                    from include/linux/spinlock.h:56,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/slab.h:16,
                    from include/linux/resource_ext.h:11,
                    from include/linux/acpi.h:13:
   drivers/leds/leds-as3668.c:145:17: warning: format '%tx' expects argument of type 'unsigned ptrdiff_t', but argument 4 has type 'int' [-Wformat=]
     145 |                 "chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/dynamic_debug.h:224:29: note: in definition of macro '__dynamic_func_call_cls'
     224 |                 func(&id, ##__VA_ARGS__);                       \
         |                             ^~~~~~~~~~~
   include/linux/dynamic_debug.h:250:9: note: in expansion of macro '_dynamic_func_call_cls'
     250 |         _dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
         |         ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/dynamic_debug.h:273:9: note: in expansion of macro '_dynamic_func_call'
     273 |         _dynamic_func_call(fmt, __dynamic_dev_dbg,              \
         |         ^~~~~~~~~~~~~~~~~~
   include/linux/dev_printk.h:165:9: note: in expansion of macro 'dynamic_dev_dbg'
     165 |         dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~~~~~~~~~~
   include/linux/dev_printk.h:165:30: note: in expansion of macro 'dev_fmt'
     165 |         dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                              ^~~~~~~
   drivers/leds/leds-as3668.c:144:9: note: in expansion of macro 'dev_dbg'
     144 |         dev_dbg(&client->dev,
         |         ^~~~~~~
   drivers/leds/leds-as3668.c:145:31: note: format string is defined here
     145 |                 "chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
         |                             ~~^
         |                               |
         |                               long unsigned int
         |                             %x
   drivers/leds/leds-as3668.c:145:17: warning: format '%tx' expects argument of type 'unsigned ptrdiff_t', but argument 5 has type 'int' [-Wformat=]
     145 |                 "chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/dynamic_debug.h:224:29: note: in definition of macro '__dynamic_func_call_cls'
     224 |                 func(&id, ##__VA_ARGS__);                       \
         |                             ^~~~~~~~~~~
   include/linux/dynamic_debug.h:250:9: note: in expansion of macro '_dynamic_func_call_cls'
     250 |         _dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
         |         ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/dynamic_debug.h:273:9: note: in expansion of macro '_dynamic_func_call'
     273 |         _dynamic_func_call(fmt, __dynamic_dev_dbg,              \
         |         ^~~~~~~~~~~~~~~~~~
   include/linux/dev_printk.h:165:9: note: in expansion of macro 'dynamic_dev_dbg'
     165 |         dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~~~~~~~~~~
   include/linux/dev_printk.h:165:30: note: in expansion of macro 'dev_fmt'
     165 |         dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                              ^~~~~~~
   drivers/leds/leds-as3668.c:144:9: note: in expansion of macro 'dev_dbg'
     144 |         dev_dbg(&client->dev,
         |         ^~~~~~~
   drivers/leds/leds-as3668.c:145:49: note: format string is defined here
     145 |                 "chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
         |                                               ~~^
         |                                                 |
         |                                                 long unsigned int
         |                                               %x
   drivers/leds/leds-as3668.c:145:17: warning: format '%tx' expects argument of type 'unsigned ptrdiff_t', but argument 6 has type 'int' [-Wformat=]
     145 |                 "chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/dynamic_debug.h:224:29: note: in definition of macro '__dynamic_func_call_cls'


vim +55 drivers/leds/leds-as3668.c

    49	
    50	static int as3668_write_value(struct i2c_client *client, u8 reg, u8 value)
    51	{
    52		int err = i2c_smbus_write_byte_data(client, reg, value);
    53	
    54		if (err)
  > 55			dev_err(&client->dev, "error writing to reg 0x%tx, returned %d", reg, err);
    56	
    57		return err;
    58	}
    59	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v4 2/2] leds: as3668: Driver for the ams Osram 4-channel i2c LED driver

[kernel test robot]

Hi Lukas,

kernel test robot noticed the following build errors:

[auto build test ERROR on lee-leds/for-leds-next]
[also build test ERROR on linus/master v6.15 next-20250606]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Lukas-Timmermann/dt-bindings-leds-Add-new-as3668-support/20250608-055330
base:   https://git.kernel.org/pub/scm/linux/kernel/git/lee/leds.git for-leds-next
patch link:    https://lore.kernel.org/r/20250607215049.29259-3-linux%40timmermann.space
patch subject: [PATCH v4 2/2] leds: as3668: Driver for the ams Osram 4-channel i2c LED driver
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20250608/202506081754.yXYFC7WL-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250608/202506081754.yXYFC7WL-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506081754.yXYFC7WL-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/leds/leds-as3668.c:137:16: error: call to undeclared function 'FIELD_GET'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     137 |         chip_serial = FIELD_GET(AS3668_CHIP_ID2_SERIAL_MASK, chip_id2);
         |                       ^
   1 error generated.


vim +/FIELD_GET +137 drivers/leds/leds-as3668.c

   117	
   118	static int as3668_probe(struct i2c_client *client)
   119	{
   120		u8 chip_id1, chip_id2, chip_serial, chip_rev;
   121		struct as3668 *as3668;
   122	
   123		/* Check for sensible i2c address */
   124		if (client->addr != 0x42)
   125			return dev_err_probe(&client->dev, -EFAULT,
   126					     "unexpected address for as3668 device\n");
   127	
   128		/* Read identifier from chip */
   129		chip_id1 = as3668_read_value(client, AS3668_CHIP_ID1);
   130	
   131		if (chip_id1 != AS3668_CHIP_IDENT)
   132			return dev_err_probe(&client->dev, -ENODEV,
   133					"chip reported wrong id: 0x%tx\n", chip_id1);
   134	
   135		/* Check the revision*/
   136		chip_id2 = as3668_read_value(client, AS3668_CHIP_ID2);
 > 137		chip_serial = FIELD_GET(AS3668_CHIP_ID2_SERIAL_MASK, chip_id2);
   138		chip_rev = FIELD_GET(AS3668_CHIP_ID2_REV_MASK, chip_id2);
   139	
   140		if (chip_rev != AS3668_CHIP_REV1)
   141			dev_warn(&client->dev, "unexpected chip revision\n");
   142	
   143		/* Print out information about the chip */
   144		dev_dbg(&client->dev,
   145			"chip_id: 0x%tx | chip_id2: 0x%tx | chip_serial: 0x%tx | chip_rev: 0x%tx\n",
   146			chip_id1, chip_id2, chip_serial, chip_rev);
   147	
   148		as3668 = devm_kzalloc(&client->dev, struct_size(as3668, leds, AS3668_MAX_LEDS), GFP_KERNEL);
   149		as3668->client = client;
   150	
   151		as3668_dt_init(as3668);
   152	
   153		/* Initialize the chip */
   154		as3668_write_value(client, AS3668_CURRX_CONTROL, 0x55);
   155		as3668_write_value(client, AS3668_CURR1, 0x00);
   156		as3668_write_value(client, AS3668_CURR2, 0x00);
   157		as3668_write_value(client, AS3668_CURR3, 0x00);
   158		as3668_write_value(client, AS3668_CURR4, 0x00);
   159	
   160		return 0;
   161	}
   162	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v4 1/2] dt-bindings: leds: Add new as3668 support

[Krzysztof Kozlowski]

On 07/06/2025 23:50, Lukas Timmermann wrote:
> This patch documents the device tree bindings for

Your previous style was correct. I don't get why you changed it to
incorrect "This patch".

See longer explanation here:
https://elixir.bootlin.com/linux/v5.17.1/source/Documentation/process/submitting-patches.rst#L95

> the OSRAM AS3668 LED driver. Note that the bindings
> are not entirely complete, as the GPIO/Audio Input pin
> is undocumented. The hardware used for testing this patch series
> does not allow modification, so this pin has been omitted.
> 
> Signed-off-by: Lukas Timmermann <linux@timmermann.space>
> ---

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

<form letter>
This is an automated instruction, just in case, because many review tags
are being ignored. If you know the process, just skip it entirely
(please do not feel offended by me posting it here - no bad intentions
intended, no patronizing, I just want to avoid wasted efforts). If you
do not know the process, here is a short explanation:

Please add Acked-by/Reviewed-by/Tested-by tags when posting new versions
of patchset, under or above your Signed-off-by tag, unless patch changed
significantly (e.g. new properties added to the DT bindings). Tag is
"received", when provided in a message replied to you on the mailing
list. Tools like b4 can help here ('b4 trailers -u ...'). However,
there's no need to repost patches *only* to add the tags. The upstream
maintainer will do that for tags received on the version they apply.

Full context and explanation:
https://elixir.bootlin.com/linux/v6.15/source/Documentation/process/submitting-patches.rst#L591
</form letter>

Best regards,
Krzysztof