[PATCH v3 0/2] Add Support for LTC3220 18 Channel LED Driver

[PATCH v3 0/2] Add Support for LTC3220 18 Channel LED Driver

[Edelweise Escala]

The LTC3220/LTC3220-1 is a multi-display LED driver, which contains a
high-efficiency, low-noise charge pump to provide power to up to
18 LED current sources. The LEDs are individually configurable to
64-step linear brightness control, blinking and gradation control
via 2-wire I2C interface. The blinking and gradation configuration
is shared across all LED.

LTC3220 has a quick write function which allows changing the brightness
on all LEDS simultaneously when the brightness is changed on led 1.
For this we made quick write a device property which user can set on the 
device tree. We would like to know if this approach is alright?
Another way we might want to know is, is it alright to just make a
virtual led for the quick write function. Changing brightness on 
the virtual led will change the brightness for all.

Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
---
Changes in v3:
- Dropped quick-write on bindings and added aggregated led instead.
- Add aggregated led example.
- Modify quick write to check if there is aggregated led, if there is
  aggregated led enable quick write.
- Use DEFINE_SIMPLE_DEV_PM_OPS instead of SIMPLE_DEV_PM_OPS.
- Link to v2: https://lore.kernel.org/r/20260112-ltc3220-driver-v2-0-d043058fc4df@analog.com

Changes in v2:
leds-ltc3220.yaml changes
-Fix wrapping on description
-Improve description and commit messge to describe hardware
-Drop ltc3220-1
-Drop charge pump
ltc3220.c changes
-Fix wrapping
-Drop ltc3220-1
-Drop devname_mandatory
- Link to v1: https://lore.kernel.org/r/20260106-ltc3220-driver-v1-0-73601d6f1649@analog.com

---
Edelweise Escala (2):
      dt-bindings: leds: Add LTC3220 18 channel LED Driver
      leds: ltc3220: Add Support for LTC3220 18 channel LED Driver

 .../devicetree/bindings/leds/leds-ltc3220.yaml     | 120 ++++++
 MAINTAINERS                                        |   8 +
 drivers/leds/Kconfig                               |  10 +
 drivers/leds/Makefile                              |   1 +
 drivers/leds/leds-ltc3220.c                        | 457 +++++++++++++++++++++
 5 files changed, 596 insertions(+)
---
base-commit: 8856d7fe1758937ac528770f552ec58c388c255b
change-id: 20260106-ltc3220-driver-f9ab6cc9d1e4

Best regards,
-- 
Edelweise Escala <edelweise.escala@analog.com>

[PATCH v3 1/2] dt-bindings: leds: Add LTC3220 18 channel LED Driver

[Edelweise Escala]

Document device tree bindings for the LTC3220 18-channel LED driver
with I2C interface, individual brightness control, and hardware-assisted
blink/gradation features.

Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
---
 .../devicetree/bindings/leds/leds-ltc3220.yaml     | 120 +++++++++++++++++++++
 MAINTAINERS                                        |   7 ++
 2 files changed, 127 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml b/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
new file mode 100644
index 000000000000..6274c6c6ad79
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
@@ -0,0 +1,120 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/leds-ltc3220.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices LTC3220 LED Driver
+
+maintainers:
+  - Edelweise Escala <edelweise.escala@analog.com>
+
+description:
+  The LTC3220 is a multi-display LED driver, which contains a high-efficiency,
+  low-noise charge pump to provide power to up to 18 LED current sources.
+  The LEDs are individually configurable to 64-step linear brightness control,
+  blinking and gradation control via 2-wire I2C interface.
+
+  For more product information please see the link below
+    https://www.analog.com/en/products/ltc3220.html
+
+properties:
+  compatible:
+    const: adi,ltc3220
+
+  reg:
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  reset-gpios:
+    maxItems: 1
+
+patternProperties:
+  '^led@([1-9]|1[0-8])$':
+    type: object
+    $ref: /schemas/leds/common.yaml#
+    unevaluatedProperties: false
+    properties:
+      reg:
+        description:
+          Output channel for the LED (1-18 maps to LED outputs D1-D18).
+          For aggregated LED control, define only one LED node with reg = <1>
+          and use led-sources to list all controlled outputs. Only reg 1 should
+          be present when using led-sources.
+        minimum: 1
+        maximum: 18
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    // Independent LEDs
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@1c {
+            compatible = "adi,ltc3220";
+            reg = <0x1c>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+            reset-gpios = <&gpio 17 GPIO_ACTIVE_LOW>;
+
+            led@1 {
+                reg = <1>;
+                function = LED_FUNCTION_INDICATOR;
+                function-enumerator = <1>;
+            };
+
+            led@2 {
+                reg = <2>;
+                function = LED_FUNCTION_INDICATOR;
+                function-enumerator = <2>;
+            };
+
+            led@3 {
+                reg = <3>;
+                function = LED_FUNCTION_INDICATOR;
+                function-enumerator = <3>;
+            };
+        };
+    };
+
+  - |
+    // Aggregated LED
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@1c {
+            compatible = "adi,ltc3220";
+            reg = <0x1c>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            led@1 {
+                reg = <1>;
+                led-sources = <1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18>;
+                function = LED_FUNCTION_BACKLIGHT;
+            };
+        };
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 327d74ca7ecb..d640c35d1f93 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14955,6 +14955,13 @@ W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
 F:	drivers/iio/temperature/ltc2983.c
 
+LTC3220 LED DRIVER
+M:	Edelweise Escala <edelweise.escala@analog.com>
+L:	linux-leds@vger.kernel.org
+S:	Maintained
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
+
 LTC4282 HARDWARE MONITOR DRIVER
 M:	Nuno Sa <nuno.sa@analog.com>
 L:	linux-hwmon@vger.kernel.org

-- 
2.43.0

Re: [PATCH v3 1/2] dt-bindings: leds: Add LTC3220 18 channel LED Driver

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 1880 bytes --]

On Tue, Jan 20, 2026 at 01:35:06PM +0800, Edelweise Escala wrote:
> Document device tree bindings for the LTC3220 18-channel LED driver
> with I2C interface, individual brightness control, and hardware-assisted
> blink/gradation features.
> 
> Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
> ---
>  .../devicetree/bindings/leds/leds-ltc3220.yaml     | 120 +++++++++++++++++++++
>  MAINTAINERS                                        |   7 ++
>  2 files changed, 127 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml b/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
> new file mode 100644
> index 000000000000..6274c6c6ad79
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml

filename should match the compatible, so s/leds-/adi,/

Otherwise, this looks pretty okay to me. With that changed,
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: changes-requested

Cheers,
Conor.

> @@ -0,0 +1,120 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/leds-ltc3220.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC3220 LED Driver
> +
> +maintainers:
> +  - Edelweise Escala <edelweise.escala@analog.com>
> +
> +description:
> +  The LTC3220 is a multi-display LED driver, which contains a high-efficiency,
> +  low-noise charge pump to provide power to up to 18 LED current sources.
> +  The LEDs are individually configurable to 64-step linear brightness control,
> +  blinking and gradation control via 2-wire I2C interface.
> +
> +  For more product information please see the link below
> +    https://www.analog.com/en/products/ltc3220.html
> +
> +properties:
> +  compatible:
> +    const: adi,ltc3220

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RE: [PATCH v3 1/2] dt-bindings: leds: Add LTC3220 18 channel LED Driver

[Escala, Edelweise]

> -----Original Message-----
> From: Conor Dooley <conor@kernel.org>
> Sent: Wednesday, January 21, 2026 3:56 AM
> To: Escala, Edelweise <Edelweise.Escala@analog.com>
> Cc: Lee Jones <lee@kernel.org>; Pavel Machek <pavel@kernel.org>; Rob Herring
> <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor Dooley
> <conor+dt@kernel.org>; linux-leds@vger.kernel.org; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v3 1/2] dt-bindings: leds: Add LTC3220 18 channel LED Driver
> 
> [External]
> 
> On Tue, Jan 20, 2026 at 01:35:06PM +0800, Edelweise Escala wrote:
> > Document device tree bindings for the LTC3220 18-channel LED driver
> > with I2C interface, individual brightness control, and
> > hardware-assisted blink/gradation features.
> >
> > Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
> > ---
> >  .../devicetree/bindings/leds/leds-ltc3220.yaml     | 120
> +++++++++++++++++++++
> >  MAINTAINERS                                        |   7 ++
> >  2 files changed, 127 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
> > b/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
> > new file mode 100644
> > index 000000000000..6274c6c6ad79
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
> 
> filename should match the compatible, so s/leds-/adi,/
> 
> Otherwise, this looks pretty okay to me. With that changed,
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> pw-bot: changes-requested
> 
> Cheers,
> Conor.
> 

Noted on this. Filename will be changed to adi,ltc3220.yaml

Best Regards,
Edelweise Escala


> > @@ -0,0 +1,120 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/leds/leds-ltc3220.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Analog Devices LTC3220 LED Driver
> > +
> > +maintainers:
> > +  - Edelweise Escala <edelweise.escala@analog.com>
> > +
> > +description:
> > +  The LTC3220 is a multi-display LED driver, which contains a
> > +high-efficiency,
> > +  low-noise charge pump to provide power to up to 18 LED current sources.
> > +  The LEDs are individually configurable to 64-step linear brightness
> > +control,
> > +  blinking and gradation control via 2-wire I2C interface.
> > +
> > +  For more product information please see the link below
> > +    https://www.analog.com/en/products/ltc3220.html
> > +
> > +properties:
> > +  compatible:
> > +    const: adi,ltc3220

Re: [PATCH v3 1/2] dt-bindings: leds: Add LTC3220 18 channel LED Driver

[Krzysztof Kozlowski]

On 20/01/2026 06:35, Edelweise Escala wrote:
> Document device tree bindings for the LTC3220 18-channel LED driver
> with I2C interface, individual brightness control, and hardware-assisted
> blink/gradation features.
> 
> Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
> ---
>  .../devicetree/bindings/leds/leds-ltc3220.yaml     | 120 +++++++++++++++++++++
>  MAINTAINERS                                        |   7 ++
>  2 files changed, 127 insertions(+)


Please go to v1 and implement ALL comments.

Best regards,
Krzysztof

RE: [PATCH v3 1/2] dt-bindings: leds: Add LTC3220 18 channel LED Driver

[Escala, Edelweise]

> On 20/01/2026 06:35, Edelweise Escala wrote:
> > Document device tree bindings for the LTC3220 18-channel LED driver
> > with I2C interface, individual brightness control, and
> > hardware-assisted blink/gradation features.
> >
> > Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
> > ---
> >  .../devicetree/bindings/leds/leds-ltc3220.yaml     | 120
> +++++++++++++++++++++
> >  MAINTAINERS                                        |   7 ++
> >  2 files changed, 127 insertions(+)
> 
> 
> Please go to v1 and implement ALL comments.
> 
> Best regards,
> Krzysztof

I'll recheck all comments, apologies for missing the filename comment

Best Regards,
Edelweise Escala

[PATCH v3 2/2] leds: ltc3220: Add Support for LTC3220 18 channel LED Driver

[Edelweise Escala]

Add driver for the LTC3220 18-channel LED driver
with I2C interface, individual brightness control, and hardware-assisted
blink/gradation features.

Signed-off-by: Edelweise Escala <edelweise.escala@analog.com>
---
 MAINTAINERS                 |   1 +
 drivers/leds/Kconfig        |  10 +
 drivers/leds/Makefile       |   1 +
 drivers/leds/leds-ltc3220.c | 457 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 469 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index d640c35d1f93..fda0d2963c4f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14961,6 +14961,7 @@ L:	linux-leds@vger.kernel.org
 S:	Maintained
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/leds/leds-ltc3220.yaml
+F:	drivers/leds/leds-ltc3220.c
 
 LTC4282 HARDWARE MONITOR DRIVER
 M:	Nuno Sa <nuno.sa@analog.com>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 597d7a79c988..a1c34b2deded 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -1001,6 +1001,16 @@ config LEDS_ST1202
 	  Say Y to enable support for LEDs connected to LED1202
 	  LED driver chips accessed via the I2C bus.
 
+config LEDS_LTC3220
+	tristate "LED Driver for LTC3220/LTC3220-1"
+	depends on I2C && LEDS_CLASS
+	help
+	  If you have an 18-Channel LED Driver connected to LTC3220, or LTC3220-1
+	  say Y here to enable this driver.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called ltc3220.
+
 config LEDS_TPS6105X
 	tristate "LED support for TI TPS6105X"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 8fdb45d5b439..5301568d9e00 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-$(CONFIG_LEDS_LTC3220)		+= leds-ltc3220.o
 obj-$(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-ltc3220.c b/drivers/leds/leds-ltc3220.c
new file mode 100644
index 000000000000..28825dec4214
--- /dev/null
+++ b/drivers/leds/leds-ltc3220.c
@@ -0,0 +1,457 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LTC3220 18-Channel LED Driver
+ *
+ * Copyright 2026 Analog Devices Inc.
+ *
+ * Author: Edelweise Escala <edelweise.escala@analog.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+/* LTC3220 Registers */
+#define LTC3220_COMMAND				0x00
+#define LTC3220_ULED(x)				(0x01 + (x))
+#define LTC3220_GRAD_BLINK			0x13
+
+#define LTC3220_GRAD_COUNT_UP		BIT(0)
+#define LTC3220_COMMAND_QUICK_WRITE	BIT(0)
+#define LTC3220_COMMAND_SHUTDOWN	BIT(3)
+
+#define LTC3220_LED_CURRENT_MASK	GENMASK(5, 0)
+#define LTC3220_LED_MODE_MASK		GENMASK(7, 6)
+#define LTC3220_BLINK_MASK			GENMASK(4, 3)
+#define LTC3220_GRADATION_MASK		GENMASK(2, 1)
+
+#define LTC3220_NUM_LEDS 18
+
+struct ltc3220_command_cfg {
+	bool is_aggregated;
+	bool is_shutdown;
+};
+
+struct ltc3220_uled_cfg {
+	struct ltc3220_state *ltc3220_state;
+	struct led_classdev led_cdev;
+	u8 reg_value;
+	u8 led_index;
+};
+
+struct ltc3220_grad_cfg {
+	bool is_increasing;
+	u8 gradation_period_ms;
+};
+
+struct ltc3220_state {
+	struct ltc3220_command_cfg command_cfg;
+	struct ltc3220_uled_cfg uled_cfg[LTC3220_NUM_LEDS];
+	struct ltc3220_grad_cfg grad_cfg;
+	struct i2c_client *client;
+	u8 blink_mode;
+};
+
+static int ltc3220_set_command(struct ltc3220_state *ltc3220_state)
+{
+	struct i2c_client *client = ltc3220_state->client;
+	u8 reg_val;
+
+	reg_val = FIELD_PREP(LTC3220_COMMAND_SHUTDOWN,
+			     ltc3220_state->command_cfg.is_shutdown);
+	reg_val |= FIELD_PREP(LTC3220_COMMAND_QUICK_WRITE,
+			      ltc3220_state->command_cfg.is_aggregated);
+
+	return i2c_smbus_write_byte_data(client, LTC3220_COMMAND, reg_val);
+}
+
+static int ltc3220_shutdown(struct ltc3220_state *ltc3220_state)
+{
+	int ret;
+
+	ltc3220_state->command_cfg.is_shutdown = true;
+	ret = ltc3220_set_command(ltc3220_state);
+	if (ret < 0)
+		ltc3220_state->command_cfg.is_shutdown = false;
+
+	return ret;
+}
+
+static int ltc3220_resume_from_shutdown(struct ltc3220_state *ltc3220_state)
+{
+	int ret;
+
+	ltc3220_state->command_cfg.is_shutdown = false;
+	ret = ltc3220_set_command(ltc3220_state);
+	if (ret < 0)
+		ltc3220_state->command_cfg.is_shutdown = true;
+
+	return ret;
+}
+
+/*
+ * Set LED brightness and mode.
+ * The brightness value determines both the LED current and operating mode:
+ * 0-63:    Normal mode - LED current from 0-63 (off to full brightness)
+ * 64-127:  Blink mode - LED blinks with current level (brightness - 64)
+ * 128-191: Gradation mode - LED gradually changes brightness (brightness - 128)
+ * 192-255: GPO mode - LED operates as general purpose output (brightness - 192)
+ */
+static int ltc3220_set_led_data(struct led_classdev *led_cdev,
+				enum led_brightness brightness)
+{
+	struct ltc3220_state *ltc3220_state;
+	struct ltc3220_uled_cfg *uled_cfg;
+	int ret;
+	int i;
+
+	uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, led_cdev);
+	ltc3220_state = uled_cfg->ltc3220_state;
+
+	ret = i2c_smbus_write_byte_data(ltc3220_state->client,
+			LTC3220_ULED(uled_cfg->led_index), brightness);
+	if (ret < 0)
+		return ret;
+
+	uled_cfg->reg_value = brightness;
+
+	/*
+	 * When aggregated LED mode is enabled, writing to LED 1 updates all
+	 * LEDs simultaneously via quick-write mode. Update cached values for
+	 * all LEDs to reflect the synchronized state.
+	 */
+	if (ltc3220_state->command_cfg.is_aggregated && uled_cfg->led_index == 0) {
+		for (i = 0; i < LTC3220_NUM_LEDS; i++)
+			ltc3220_state->uled_cfg[i].reg_value = brightness;
+	}
+
+	return 0;
+}
+
+static enum led_brightness ltc3220_get_led_data(struct led_classdev *led_cdev)
+{
+	struct ltc3220_uled_cfg *uled_cfg;
+
+	uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, led_cdev);
+
+	return uled_cfg->reg_value;
+}
+
+static int ltc3220_set_blink_and_gradation(struct ltc3220_state *ltc3220_state,
+		    u8 blink_cfg, u8 gradation_period_ms, bool is_increasing)
+{
+	struct i2c_client *client = ltc3220_state->client;
+	u8 reg_val;
+
+	reg_val = FIELD_PREP(LTC3220_BLINK_MASK, blink_cfg);
+	reg_val |= FIELD_PREP(LTC3220_GRADATION_MASK, gradation_period_ms);
+	reg_val |= FIELD_PREP(LTC3220_GRAD_COUNT_UP, is_increasing);
+
+	return i2c_smbus_write_byte_data(client, LTC3220_GRAD_BLINK, reg_val);
+}
+
+/*
+ * LTC3220 pattern support for hardware-assisted breathing/gradation.
+ * The hardware supports 3 gradation ramp time 240ms, 480ms, 960ms)
+ * and can ramp up or down.
+ *
+ * Pattern array interpretation:
+ *   pattern[0].brightness = start brightness (0-63)
+ *   pattern[0].delta_t = ramp time in milliseconds
+ *   pattern[1].brightness = end brightness (0-63)
+ *   pattern[1].delta_t = (optional, can be 0 or same as pattern[0].delta_t)
+ */
+static int ltc3220_pattern_set(struct led_classdev *led_cdev,
+			       struct led_pattern *pattern,
+			       u32 len, int repeat)
+{
+	struct ltc3220_state *ltc3220_state;
+	struct ltc3220_uled_cfg *uled_cfg;
+	u8 gradation_period;
+	u8 start_brightness;
+	u8 end_brightness;
+	bool is_increasing;
+	int ret;
+
+	if (len != 2)
+		return -EINVAL;
+
+	uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, led_cdev);
+	ltc3220_state = uled_cfg->ltc3220_state;
+
+	start_brightness = pattern[0].brightness & LTC3220_LED_CURRENT_MASK;
+	end_brightness = pattern[1].brightness & LTC3220_LED_CURRENT_MASK;
+
+	is_increasing = end_brightness > start_brightness;
+
+	if (pattern[0].delta_t == 0)
+		gradation_period = 0;
+	else if (pattern[0].delta_t <= 240)
+		gradation_period = 1;
+	else if (pattern[0].delta_t <= 480)
+		gradation_period = 2;
+	else
+		gradation_period = 3;
+
+	ret = ltc3220_set_blink_and_gradation(ltc3220_state,
+					       ltc3220_state->blink_mode,
+					       gradation_period,
+					       is_increasing);
+	if (ret < 0)
+		return ret;
+
+	ltc3220_state->grad_cfg.gradation_period_ms = gradation_period;
+	ltc3220_state->grad_cfg.is_increasing = is_increasing;
+
+	ret = ltc3220_set_led_data(led_cdev, start_brightness);
+	if (ret < 0)
+		return ret;
+
+	return ltc3220_set_led_data(led_cdev, 128 + end_brightness);
+}
+
+static int ltc3220_pattern_clear(struct led_classdev *led_cdev)
+{
+	struct ltc3220_state *ltc3220_state;
+	struct ltc3220_uled_cfg *uled_cfg;
+	int ret;
+
+	uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, led_cdev);
+	ltc3220_state = uled_cfg->ltc3220_state;
+
+	ret = ltc3220_set_blink_and_gradation(ltc3220_state,
+					       ltc3220_state->blink_mode,
+					       0, false);
+	if (ret < 0)
+		return ret;
+
+	ltc3220_state->grad_cfg.gradation_period_ms = 0;
+	ltc3220_state->grad_cfg.is_increasing = false;
+
+	return 0;
+}
+
+/*
+ * LTC3220 has a global blink configuration that affects all LEDs.
+ * This implementation allows per-LED blink requests, but the blink timing
+ * will be shared across all LEDs. The delay values are mapped to the
+ * hardware's discrete blink rates.
+ */
+static int ltc3220_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)
+{
+	struct ltc3220_state *ltc3220_state;
+	struct ltc3220_uled_cfg *uled_cfg;
+	unsigned long period;
+	u8 blink_mode;
+	int ret;
+
+	uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, led_cdev);
+	ltc3220_state = uled_cfg->ltc3220_state;
+
+	if (*delay_on == 0 && *delay_off == 0) {
+		blink_mode = 1;
+		*delay_on = 500;
+		*delay_off = 500;
+	} else {
+		period = *delay_on + *delay_off;
+
+		if (period <= 750) {
+			blink_mode = 0;
+			*delay_on = 250;
+			*delay_off = 250;
+		} else if (period <= 1500) {
+			blink_mode = 1;
+			*delay_on = 500;
+			*delay_off = 500;
+		} else if (period <= 3000) {
+			blink_mode = 2;
+			*delay_on = 1000;
+			*delay_off = 1000;
+		} else {
+			blink_mode = 3;
+			*delay_on = 2000;
+			*delay_off = 2000;
+		}
+	}
+
+	ret = ltc3220_set_blink_and_gradation(ltc3220_state, blink_mode,
+					       ltc3220_state->grad_cfg.gradation_period_ms,
+					       ltc3220_state->grad_cfg.is_increasing);
+	if (ret < 0)
+		return ret;
+
+	ltc3220_state->blink_mode = blink_mode;
+
+	return 0;
+}
+
+static void ltc3220_reset_gpio_action(void *data)
+{
+	struct gpio_desc *reset_gpio = data;
+
+	gpiod_set_value_cansleep(reset_gpio, 1);
+}
+
+static int ltc3220_reset(struct ltc3220_state *ltc3220_state, struct i2c_client *client)
+{
+	struct gpio_desc *reset_gpio;
+	int ret;
+	int i;
+
+	reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(reset_gpio))
+		return dev_err_probe(&client->dev, PTR_ERR(reset_gpio),
+							"Failed to set reset GPIO\n");
+
+	if (reset_gpio) {
+		gpiod_set_value_cansleep(reset_gpio, 0);
+
+		ret = devm_add_action_or_reset(&client->dev, ltc3220_reset_gpio_action, reset_gpio);
+		if (ret)
+			return ret;
+
+	} else {
+		ret = ltc3220_set_command(ltc3220_state);
+		if (ret < 0)
+			return ret;
+
+		for (i = 0; i < LTC3220_NUM_LEDS; i++) {
+			ret = i2c_smbus_write_byte_data(client, LTC3220_ULED(i), 0);
+			if (ret < 0)
+				return ret;
+		}
+
+		ret = ltc3220_set_blink_and_gradation(ltc3220_state, 0, 0, 0);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ltc3220_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ltc3220_state *ltc3220_state = i2c_get_clientdata(client);
+
+	return ltc3220_shutdown(ltc3220_state);
+}
+
+static int ltc3220_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ltc3220_state *ltc3220_state = i2c_get_clientdata(client);
+
+	return ltc3220_resume_from_shutdown(ltc3220_state);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ltc3220_pm_ops, ltc3220_suspend, ltc3220_resume);
+
+static int ltc3220_probe(struct i2c_client *client)
+{
+	struct ltc3220_state *ltc3220_state;
+	bool aggregated_led_found = false;
+	int num_leds = 0;
+	u8 i = 0;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return dev_err_probe(&client->dev, -EIO, "SMBUS Byte Data not Supported\n");
+
+	ltc3220_state = devm_kzalloc(&client->dev, sizeof(*ltc3220_state), GFP_KERNEL);
+	if (!ltc3220_state)
+		return -ENOMEM;
+
+	ltc3220_state->client = client;
+	i2c_set_clientdata(client, ltc3220_state);
+
+	ret = ltc3220_reset(ltc3220_state, client);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "Failed to reset device\n");
+
+	device_for_each_child_node_scoped(&client->dev, child) {
+		struct led_init_data init_data = {};
+		struct ltc3220_uled_cfg *led;
+		u32 source;
+
+		ret = fwnode_property_read_u32(child, "reg", &source);
+		if (ret)
+			return dev_err_probe(&client->dev, ret, "Couldn't read LED address\n");
+
+		if (!source || source > LTC3220_NUM_LEDS)
+			return dev_err_probe(&client->dev, -EINVAL, "LED address out of range\n");
+
+		init_data.fwnode = child;
+		init_data.devicename = "ltc3220";
+
+		if (fwnode_property_present(child, "led-sources")) {
+			if (source != 1)
+				return dev_err_probe(&client->dev, -EINVAL,
+						     "Aggregated LED must use reg = <1>\n");
+
+			if (aggregated_led_found)
+				return dev_err_probe(&client->dev, -EINVAL,
+						     "Only one aggregated LED node allowed\n");
+
+			aggregated_led_found = true;
+			ltc3220_state->command_cfg.is_aggregated = true;
+			ret = ltc3220_set_command(ltc3220_state);
+			if (ret < 0)
+				return dev_err_probe(&client->dev, ret, "Failed to set command\n");
+		}
+
+		num_leds++;
+
+		/* LED node reg/index/address goes from 1 to 18 */
+		i = source - 1;
+		led = &ltc3220_state->uled_cfg[i];
+		led->led_index = i;
+		led->reg_value = 0;
+		led->ltc3220_state = ltc3220_state;
+		led->led_cdev.brightness_set_blocking = ltc3220_set_led_data;
+		led->led_cdev.brightness_get = ltc3220_get_led_data;
+		led->led_cdev.max_brightness = 255;
+		led->led_cdev.blink_set = ltc3220_blink_set;
+		led->led_cdev.pattern_set = ltc3220_pattern_set;
+		led->led_cdev.pattern_clear = ltc3220_pattern_clear;
+
+		ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data);
+		if (ret)
+			return dev_err_probe(&client->dev, ret,
+							     "Failed to register LED class device\n");
+	}
+
+	if (aggregated_led_found && num_leds > 1)
+		return dev_err_probe(&client->dev, -EINVAL,
+				     "Aggregated LED cannot be combined with other LED nodes\n");
+
+	return 0;
+}
+
+static const struct of_device_id ltc3220_of_match[] = {
+	{ .compatible = "adi,ltc3220" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ltc3220_of_match);
+
+static struct i2c_driver ltc3220_led_driver = {
+	.driver = {
+		.name = "ltc3220",
+		.of_match_table = ltc3220_of_match,
+		.pm	= pm_sleep_ptr(&ltc3220_pm_ops),
+	},
+	.probe = ltc3220_probe,
+};
+module_i2c_driver(ltc3220_led_driver);
+
+MODULE_AUTHOR("Edelweise Escala <edelweise.escala@analog.com>");
+MODULE_DESCRIPTION("LED driver for LTC3220 controllers");
+MODULE_LICENSE("GPL");

-- 
2.43.0