* [PATCH v5 1/2] dt-bindings: leds: Document LTC3208 Multidisplay LED Driver
2026-06-18 22:45 [PATCH v5 0/2] Add support for LTC3208 multi-display driver Jan Carlo Roleda
@ 2026-06-18 22:45 ` Jan Carlo Roleda
2026-06-18 22:45 ` [PATCH v5 2/2] leds: ltc3208: Add driver for " Jan Carlo Roleda
1 sibling, 0 replies; 4+ messages in thread
From: Jan Carlo Roleda @ 2026-06-18 22:45 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Rob Herring, Krzysztof Kozlowski,
Conor Dooley
Cc: linux-kernel, linux-leds, devicetree, Jan Carlo Roleda,
Krzysztof Kozlowski
Add Devicetree Documentation for LTC3208 Multidisplay LED Driver.
Signed-off-by: Jan Carlo Roleda <jancarlo.roleda@analog.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
.../devicetree/bindings/leds/adi,ltc3208.yaml | 181 +++++++++++++++++++++
MAINTAINERS | 7 +
2 files changed, 188 insertions(+)
diff --git a/Documentation/devicetree/bindings/leds/adi,ltc3208.yaml b/Documentation/devicetree/bindings/leds/adi,ltc3208.yaml
new file mode 100644
index 000000000000..0a01e07e0ab7
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/adi,ltc3208.yaml
@@ -0,0 +1,181 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (c) 2026 Analog Devices, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/adi,ltc3208.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LTC3208 Multidisplay LED Controller from Linear Technologies (Now Analog Devices)
+
+maintainers:
+ - Jan Carlo Roleda <jancarlo.roleda@analog.com>
+
+description:
+ The LTC3208 is a multidisplay LED controller that can support up to 1A to all
+ connected LEDs.
+
+ The datasheet for this device can be found in
+ https://www.analog.com/en/products/ltc3208.html
+
+properties:
+ compatible:
+ const: adi,ltc3208
+
+ reg:
+ maxItems: 1
+
+ "#address-cells":
+ const: 1
+
+ "#size-cells":
+ const: 0
+
+ adi,disable-camhl-pin:
+ type: boolean
+ description:
+ Configures whether the external CAMHL pin is disabled.
+ If disabled then the output pins associated with CAM will always select
+ the CAM register's high half-byte brightness.
+
+ adi,cfg-enrgbs-pin:
+ type: boolean
+ description:
+ Configures which channel the ENRGBS pin toggles when it receives a signal.
+ ENRGBS pin controls the SUB channel's output pins if this is set,
+ or RGB channel's output pins if this is unset.
+
+ adi,disable-rgb-aux4-dropout:
+ type: boolean
+ description:
+ Configures the RGB and AUX4 dropout signals to be disabled.
+
+ adi,aux1-channel:
+ $ref: /schemas/types.yaml#/definitions/string
+ description:
+ LED Channel that the AUX1 output pin mirrors its brightness level from.
+ enum: [aux, main, sub, cam]
+ default: aux
+
+ adi,aux2-channel:
+ $ref: /schemas/types.yaml#/definitions/string
+ description:
+ LED Channel that the AUX2 output pin mirrors its brightness level from.
+ enum: [aux, main, sub, cam]
+ default: aux
+
+ adi,aux3-channel:
+ $ref: /schemas/types.yaml#/definitions/string
+ description:
+ LED Channel that the AUX3 output pin mirrors its brightness level from.
+ enum: [aux, main, sub, cam]
+ default: aux
+
+ adi,aux4-channel:
+ $ref: /schemas/types.yaml#/definitions/string
+ description:
+ LED Channel that the AUX4 output pin mirrors its brightness level from.
+ enum: [aux, main, sub, cam]
+ default: aux
+
+patternProperties:
+ "^led@[0-7]$":
+ type: object
+ $ref: /schemas/leds/common.yaml#
+ unevaluatedProperties: false
+ properties:
+ reg:
+ description:
+ LED Channel Number. each channel maps to a specific channel group used
+ to configure the brightness level of the output pins corresponding to
+ the channel.
+ enum:
+ - 0 # Main Channel (8-bit brightness)
+ - 1 # Sub Channel (8-bit brightness)
+ - 2 # AUX Channel (4-bit brightness)
+ - 3 # Camera Channel, Low-side byte (4-bit brightness)
+ - 4 # Camera Channel, High-side byte (4-bit brightness)
+ - 5 # Red Channel (4-bit brightness)
+ - 6 # Blue Channel (4-bit brightness)
+ - 7 # Green Channel (4-bit brightness)
+ required:
+ - reg
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/leds/common.h>
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ led-controller@1b {
+ compatible = "adi,ltc3208";
+ reg = <0x1b>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ adi,disable-camhl-pin;
+ adi,cfg-enrgbs-pin;
+ adi,disable-rgb-aux4-dropout;
+
+ /* MAIN */
+ led@0 {
+ reg = <0>;
+ function = LED_FUNCTION_ACTIVITY;
+ color = <LED_COLOR_ID_WHITE>;
+ };
+
+ /* SUB */
+ led@1 {
+ reg = <1>;
+ function = LED_FUNCTION_ACTIVITY;
+ color = <LED_COLOR_ID_WHITE>;
+ };
+
+ /* AUX */
+ led@2 {
+ reg = <2>;
+ function = LED_FUNCTION_ACTIVITY;
+ color = <LED_COLOR_ID_WHITE>;
+ };
+
+ /* CAMLO */
+ led@3 {
+ reg = <3>;
+ function = LED_FUNCTION_FLASH;
+ color = <LED_COLOR_ID_WHITE>;
+ };
+
+ /* CAMHI */
+ led@4 {
+ reg = <4>;
+ function = LED_FUNCTION_FLASH;
+ color = <LED_COLOR_ID_WHITE>;
+ };
+
+ /* RED */
+ led@5 {
+ reg = <5>;
+ function = LED_FUNCTION_INDICATOR;
+ color = <LED_COLOR_ID_RED>;
+ };
+
+ /* BLUE */
+ led@6 {
+ reg = <6>;
+ function = LED_FUNCTION_INDICATOR;
+ color = <LED_COLOR_ID_BLUE>;
+ };
+
+ /* GREEN */
+ led@7 {
+ reg = <7>;
+ function = LED_FUNCTION_INDICATOR;
+ color = <LED_COLOR_ID_GREEN>;
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2fb1c75afd16..2fd6ffdaaf04 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15223,6 +15223,13 @@ W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
F: drivers/iio/temperature/ltc2983.c
+LTC3208 LED DRIVER
+M: Jan Carlo Roleda <jancarlo.roleda@analog.com>
+L: linux-leds@vger.kernel.org
+S: Maintained
+W: https://ez.analog.com/linux-software-drivers
+F: Documentation/devicetree/bindings/leds/adi,ltc3208.yaml
+
LTC4282 HARDWARE MONITOR DRIVER
M: Nuno Sa <nuno.sa@analog.com>
L: linux-hwmon@vger.kernel.org
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v5 2/2] leds: ltc3208: Add driver for LTC3208 Multidisplay LED Driver
2026-06-18 22:45 [PATCH v5 0/2] Add support for LTC3208 multi-display driver Jan Carlo Roleda
2026-06-18 22:45 ` [PATCH v5 1/2] dt-bindings: leds: Document LTC3208 Multidisplay LED Driver Jan Carlo Roleda
@ 2026-06-18 22:45 ` Jan Carlo Roleda
2026-06-18 22:56 ` sashiko-bot
1 sibling, 1 reply; 4+ messages in thread
From: Jan Carlo Roleda @ 2026-06-18 22:45 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Rob Herring, Krzysztof Kozlowski,
Conor Dooley
Cc: linux-kernel, linux-leds, devicetree, Jan Carlo Roleda
Kernel driver implementation for LTC3208 Multidisplay LED Driver.
The LTC3208 is a Multi-display LED driver, designed to control up to
7 distinct LED channels (MAIN, SUB, AUX, CAMHI, CAMLO, RED, GREEN, BLUE),
each configurable with its own current level that is equally set to its
respective output current source pins for external LEDs.
It is programmed via the I2C serial interface.
MAIN and SUB support 8-bit current level resolution,
while AUX, CAMHI/LO, RED, GREEN, and BLUE support 4-bit levels.
The AUX LED channel can be configured to mirror the CAM, SUB, and MAIN
channel current levels, or as its own independent AUX channel.
The CAM LED channel is configured as 2 separate CAMHI and CAMLO register
sub-channels, which currnet is selected via the CAMHL pin, or set to
CAMHI register only via setting the S_CAMHILO bit high in register G (0x7).
Signed-off-by: Jan Carlo Roleda <jancarlo.roleda@analog.com>
---
MAINTAINERS | 1 +
drivers/leds/Kconfig | 12 +++
drivers/leds/Makefile | 1 +
drivers/leds/leds-ltc3208.c | 239 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 253 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 2fd6ffdaaf04..e3b59485ecb3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15229,6 +15229,7 @@ L: linux-leds@vger.kernel.org
S: Maintained
W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/leds/adi,ltc3208.yaml
+F: drivers/leds/leds-ltc3208.c
LTC4282 HARDWARE MONITOR DRIVER
M: Nuno Sa <nuno.sa@analog.com>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f4a0a3c8c870..d917ce3b72f4 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -1028,6 +1028,18 @@ config LEDS_ACER_A500
This option enables support for the Power Button LED of
Acer Iconia Tab A500.
+config LEDS_LTC3208
+ tristate "LED Driver for Analog Devices LTC3208"
+ depends on LEDS_CLASS && I2C
+ select REGMAP_I2C
+ help
+ Say Y to enable the LTC3208 LED driver.
+ This enables the LED device LTC3208, a 7-channel, 17-current source
+ multidisplay high-current LED driver, configured via I2C.
+
+ To compile this driver as a module, choose M here: the module will
+ be called ltc3208.
+
source "drivers/leds/blink/Kconfig"
comment "Flash and Torch LED drivers"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 7db3768912ca..0148b87e16ba 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_LEDS_LP8788) += leds-lp8788.o
obj-$(CONFIG_LEDS_LP8860) += leds-lp8860.o
obj-$(CONFIG_LEDS_LP8864) += leds-lp8864.o
obj-$(CONFIG_LEDS_LT3593) += leds-lt3593.o
+obj-$(CONFIG_LEDS_LTC3208) += leds-ltc3208.o
obj-$(CONFIG_LEDS_MAX5970) += leds-max5970.o
obj-$(CONFIG_LEDS_MAX77650) += leds-max77650.o
obj-$(CONFIG_LEDS_MAX77705) += leds-max77705.o
diff --git a/drivers/leds/leds-ltc3208.c b/drivers/leds/leds-ltc3208.c
new file mode 100644
index 000000000000..fa2b6c6acc71
--- /dev/null
+++ b/drivers/leds/leds-ltc3208.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LED driver for Analog Devices LTC3208 Multi-Display Driver
+ *
+ * Copyright 2026 Analog Devices Inc.
+ *
+ * Author: Jan Carlo Roleda <jancarlo.roleda@analog.com>
+ */
+#include <linux/bitfield.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+/* Registers */
+#define LTC3208_REG_A_GRNRED 0x1 /* Green and Red current DAC*/
+#define LTC3208_REG_B_AUXBLU 0x2 /* AUX and Blue current DAC*/
+#define LTC3208_REG_C_MAIN 0x3 /* Main current DAC */
+#define LTC3208_REG_D_SUB 0x4 /* Sub current DAC */
+#define LTC3208_REG_E_AUX_SELECT 0x5 /* AUX DAC Select */
+#define LTC3208_AUX1_MASK GENMASK(1, 0)
+#define LTC3208_AUX2_MASK GENMASK(3, 2)
+#define LTC3208_AUX3_MASK GENMASK(5, 4)
+#define LTC3208_AUX4_MASK GENMASK(7, 6)
+#define LTC3208_REG_F_CAM 0x6 /* CAM (High and Low) current DAC*/
+#define LTC3208_REG_G_OPT 0x7 /* Device Options */
+#define LTC3208_OPT_CPO_MASK GENMASK(7, 6)
+#define LTC3208_OPT_DIS_RGBDROP BIT(3)
+#define LTC3208_OPT_DIS_CAMHILO BIT(2)
+#define LTC3208_OPT_EN_RGBS BIT(1)
+
+#define LTC3208_MAX_BRIGHTNESS_4BIT 0xF
+#define LTC3208_MAX_BRIGHTNESS_8BIT 0xFF
+
+#define LTC3208_NUM_LED_GRPS 8
+#define LTC3208_NUM_AUX_LEDS 4
+
+#define LTC3208_NUM_AUX_OPT 4
+#define LTC3208_MAX_CPO_OPT 3
+
+enum ltc3208_aux_channel {
+ LTC3208_AUX_CHAN_AUX = 0,
+ LTC3208_AUX_CHAN_MAIN,
+ LTC3208_AUX_CHAN_SUB,
+ LTC3208_AUX_CHAN_CAM
+};
+
+enum ltc3208_channel {
+ LTC3208_CHAN_MAIN = 0,
+ LTC3208_CHAN_SUB,
+ LTC3208_CHAN_AUX,
+ LTC3208_CHAN_CAML,
+ LTC3208_CHAN_CAMH,
+ LTC3208_CHAN_RED,
+ LTC3208_CHAN_BLUE,
+ LTC3208_CHAN_GREEN,
+ LTC3208_CHAN_N_COUNT,
+};
+
+static const char *const ltc3208_dt_aux_channels[] = { "adi,aux1-channel",
+ "adi,aux2-channel",
+ "adi,aux3-channel",
+ "adi,aux4-channel" };
+
+static const char *const ltc3208_aux_opt[] = { "aux", "main", "sub", "cam" };
+
+struct ltc3208_led {
+ struct led_classdev cdev;
+ struct i2c_client *client;
+ struct regmap_field *rfield;
+ enum ltc3208_channel channel;
+};
+
+struct ltc3208 {
+ struct ltc3208_led leds[LTC3208_NUM_LED_GRPS];
+ struct regmap *regmap;
+};
+
+static const struct regmap_config ltc3208_regmap_cfg = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = LTC3208_REG_G_OPT,
+ .cache_type = REGCACHE_FLAT_S,
+};
+
+static const struct reg_field ltc3208_led_reg_field[LTC3208_CHAN_N_COUNT] = {
+ [LTC3208_CHAN_MAIN] = REG_FIELD(LTC3208_REG_C_MAIN, 0, 7),
+ [LTC3208_CHAN_SUB] = REG_FIELD(LTC3208_REG_D_SUB, 0, 7),
+ [LTC3208_CHAN_BLUE] = REG_FIELD(LTC3208_REG_B_AUXBLU, 0, 3),
+ [LTC3208_CHAN_AUX] = REG_FIELD(LTC3208_REG_B_AUXBLU, 4, 7),
+ [LTC3208_CHAN_CAML] = REG_FIELD(LTC3208_REG_F_CAM, 0, 3),
+ [LTC3208_CHAN_CAMH] = REG_FIELD(LTC3208_REG_F_CAM, 4, 7),
+ [LTC3208_CHAN_RED] = REG_FIELD(LTC3208_REG_A_GRNRED, 0, 3),
+ [LTC3208_CHAN_GREEN] = REG_FIELD(LTC3208_REG_A_GRNRED, 4, 7),
+};
+
+static int ltc3208_led_set_brightness(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct ltc3208_led *led =
+ container_of(led_cdev, struct ltc3208_led, cdev);
+ u8 current_level = brightness;
+
+ return regmap_field_write(led->rfield, current_level);
+}
+
+static int ltc3208_probe(struct i2c_client *client)
+{
+ enum ltc3208_aux_channel aux_channels[LTC3208_NUM_AUX_LEDS];
+ struct ltc3208 *ddata;
+ struct regmap *regmap;
+ bool disable_rgb_aux4_dropout_signal;
+ bool disable_camhl_pin;
+ bool set_sub_control_pin;
+ int ret;
+ u8 reg_val;
+
+ regmap = devm_regmap_init_i2c(client, <c3208_regmap_cfg);
+ if (IS_ERR(regmap))
+ return dev_err_probe(&client->dev, PTR_ERR(regmap),
+ "Failed to initialize regmap\n");
+
+ ddata = devm_kzalloc(&client->dev, sizeof(*ddata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+ ddata->regmap = regmap;
+
+ disable_camhl_pin = device_property_read_bool(&client->dev,
+ "adi,disable-camhl-pin");
+ set_sub_control_pin =
+ device_property_read_bool(&client->dev, "adi,cfg-enrgbs-pin");
+ disable_rgb_aux4_dropout_signal = device_property_read_bool(
+ &client->dev, "adi,disable-rgb-aux4-dropout");
+
+ reg_val = FIELD_PREP(LTC3208_OPT_EN_RGBS, set_sub_control_pin) |
+ FIELD_PREP(LTC3208_OPT_DIS_CAMHILO, disable_camhl_pin) |
+ FIELD_PREP(LTC3208_OPT_DIS_RGBDROP,
+ disable_rgb_aux4_dropout_signal);
+
+ ret = regmap_write(regmap, LTC3208_REG_G_OPT, reg_val);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "error writing to options register\n");
+
+ /* Initialize aux channel configurations */
+ for (int i = 0; i < LTC3208_NUM_AUX_LEDS; i++) {
+ ret = device_property_match_property_string(
+ &client->dev, ltc3208_dt_aux_channels[i],
+ ltc3208_aux_opt, LTC3208_NUM_AUX_OPT);
+ /* Fallback to default value (AUX) if not found */
+ if (ret == -EINVAL)
+ aux_channels[i] = LTC3208_AUX_CHAN_AUX;
+ else if (ret >= 0)
+ aux_channels[i] = ret;
+ }
+
+ reg_val = FIELD_PREP(LTC3208_AUX1_MASK, aux_channels[0]) |
+ FIELD_PREP(LTC3208_AUX2_MASK, aux_channels[1]) |
+ FIELD_PREP(LTC3208_AUX3_MASK, aux_channels[2]) |
+ FIELD_PREP(LTC3208_AUX4_MASK, aux_channels[3]);
+
+ ret = regmap_write(regmap, LTC3208_REG_E_AUX_SELECT, reg_val);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "error writing to aux channel register.\n");
+
+ i2c_set_clientdata(client, ddata);
+
+ device_for_each_child_node_scoped(&client->dev, child) {
+ struct ltc3208_led *led;
+ struct led_init_data init_data = {};
+ u32 chan;
+
+ ret = fwnode_property_read_u32(child, "reg", &chan);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to get reg value of LED\n");
+ else if (chan >= LTC3208_NUM_LED_GRPS)
+ return dev_err_probe(&client->dev, ret,
+ "%d is an invalid LED ID\n", chan);
+
+ led = &ddata->leds[chan];
+
+ led->rfield =
+ devm_regmap_field_alloc(&client->dev, ddata->regmap,
+ ltc3208_led_reg_field[chan]);
+ if (IS_ERR(led->rfield))
+ return dev_err_probe(&client->dev, PTR_ERR(led->rfield),
+ "cannot allocate regmap field\n");
+ led->client = client;
+ led->channel = chan;
+ led->cdev.brightness_set_blocking = ltc3208_led_set_brightness;
+ led->cdev.max_brightness = LTC3208_MAX_BRIGHTNESS_4BIT;
+
+ if (chan == LTC3208_CHAN_MAIN || chan == LTC3208_CHAN_SUB)
+ led->cdev.max_brightness = LTC3208_MAX_BRIGHTNESS_8BIT;
+
+ init_data.fwnode = child;
+
+ ret = devm_led_classdev_register_ext(&client->dev, &led->cdev,
+ &init_data);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "LED %u Register failed.\n", chan);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id ltc3208_match_table[] = {
+ {.compatible = "adi,ltc3208"},
+ {}
+};
+MODULE_DEVICE_TABLE(of, ltc3208_match_table);
+
+static const struct i2c_device_id ltc3208_idtable[] = {
+ { "ltc3208" },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, ltc3208_idtable);
+
+static struct i2c_driver ltc3208_driver = {
+ .driver = {
+ .name = "ltc3208",
+ .of_match_table = ltc3208_match_table,
+ },
+ .id_table = ltc3208_idtable,
+ .probe = ltc3208_probe,
+};
+module_i2c_driver(ltc3208_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jan Carlo Roleda <jancarlo.roleda@analog.com>");
+MODULE_DESCRIPTION("LTC3208 LED Driver");
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread