[v6] backlight: add new max25014 backlight driver

[PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Maud Spierings via B4 Relay 2 months, 1 week ago

From: Maud Spierings <maudspierings@gocontroll.com>

The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
with integrated boost controller.

Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>

---

In the current implementation the control registers for channel 1,
control all channels. So only one led subnode with led-sources is
supported right now. If at some point the driver functionality is
expanded the bindings can be easily extended with it.
---
 .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
 MAINTAINERS                                        |   5 +
 2 files changed, 112 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
new file mode 100644
index 000000000000..e83723224b07
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
@@ -0,0 +1,107 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim max25014 backlight controller
+
+maintainers:
+  - Maud Spierings <maudspierings@gocontroll.com>
+
+properties:
+  compatible:
+    enum:
+      - maxim,max25014
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  enable-gpios:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  power-supply:
+    description: Regulator which controls the boost converter input rail.
+
+  pwms:
+    maxItems: 1
+
+  maxim,iset:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 15
+    default: 11
+    description:
+      Value of the ISET field in the ISET register. This controls the current
+      scale of the outputs, a higher number means more current.
+
+  led@0:
+    type: object
+    description: Properties for a string of connected LEDs.
+    $ref: common.yaml#
+
+    properties:
+      reg:
+        const: 0
+
+      led-sources:
+        allOf:
+          - minItems: 1
+            maxItems: 4
+            items:
+              minimum: 0
+              maximum: 3
+            default: [0, 1, 2, 3]
+
+      default-brightness:
+        minimum: 0
+        maximum: 100
+        default: 50
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        backlight@6f {
+            compatible = "maxim,max25014";
+            reg = <0x6f>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+            enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
+            interrupt-parent = <&gpio1>;
+            interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
+            power-supply = <&reg_backlight>;
+            pwms = <&pwm1>;
+            maxim,iset = <7>;
+
+            led@0 {
+                reg = <0>;
+                led-sources = <0 1 2 3>;
+                default-brightness = <50>;
+            };
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 58c7e3f678d8..606ce086f758 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15261,6 +15261,11 @@ F:	Documentation/userspace-api/media/drivers/max2175.rst
 F:	drivers/media/i2c/max2175*
 F:	include/uapi/linux/max2175.h
 
+MAX25014 BACKLIGHT DRIVER
+M:	Maud Spierings <maudspierings@gocontroll.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
+
 MAX31335 RTC DRIVER
 M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
 L:	linux-rtc@vger.kernel.org

-- 
2.52.0

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Rob Herring 2 months ago

On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings wrote:
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with integrated boost controller.
>
> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
> 
> ---
> 
> In the current implementation the control registers for channel 1,
> control all channels. So only one led subnode with led-sources is
> supported right now. If at some point the driver functionality is
> expanded the bindings can be easily extended with it.

What's the relationship between the LEDs and backlight? It's a backlight 
plus LEDs or just 4 identical channels.

> 
> ---
>  .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
>  MAINTAINERS                                        |   5 +
>  2 files changed, 112 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> new file mode 100644
> index 000000000000..e83723224b07
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> @@ -0,0 +1,107 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Maxim max25014 backlight controller
> +
> +maintainers:
> +  - Maud Spierings <maudspierings@gocontroll.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - maxim,max25014
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +  enable-gpios:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  power-supply:
> +    description: Regulator which controls the boost converter input rail.
> +
> +  pwms:
> +    maxItems: 1
> +
> +  maxim,iset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    maximum: 15
> +    default: 11
> +    description:
> +      Value of the ISET field in the ISET register. This controls the current
> +      scale of the outputs, a higher number means more current.

We have properties for setting the current (in uA). That can't work 
here?

> +
> +  led@0:
> +    type: object
> +    description: Properties for a string of connected LEDs.
> +    $ref: common.yaml#
> +
> +    properties:
> +      reg:
> +        const: 0
> +
> +      led-sources:
> +        allOf:
> +          - minItems: 1
> +            maxItems: 4
> +            items:
> +              minimum: 0
> +              maximum: 3
> +            default: [0, 1, 2, 3]
> +
> +      default-brightness:
> +        minimum: 0
> +        maximum: 100
> +        default: 50
> +
> +    required:
> +      - reg
> +
> +    additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        backlight@6f {
> +            compatible = "maxim,max25014";
> +            reg = <0x6f>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +            enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
> +            interrupt-parent = <&gpio1>;
> +            interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
> +            power-supply = <&reg_backlight>;
> +            pwms = <&pwm1>;
> +            maxim,iset = <7>;
> +
> +            led@0 {
> +                reg = <0>;
> +                led-sources = <0 1 2 3>;
> +                default-brightness = <50>;
> +            };
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 58c7e3f678d8..606ce086f758 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15261,6 +15261,11 @@ F:	Documentation/userspace-api/media/drivers/max2175.rst
>  F:	drivers/media/i2c/max2175*
>  F:	include/uapi/linux/max2175.h
>  
> +MAX25014 BACKLIGHT DRIVER
> +M:	Maud Spierings <maudspierings@gocontroll.com>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> +
>  MAX31335 RTC DRIVER
>  M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
>  L:	linux-rtc@vger.kernel.org
> 
> -- 
> 2.52.0
>

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Maud Spierings 2 months ago

Thanks for the review.

On 12/5/25 16:07, Rob Herring wrote:
> On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings wrote:
>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>> with integrated boost controller.
>>
>> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>>
>> ---
>>
>> In the current implementation the control registers for channel 1,
>> control all channels. So only one led subnode with led-sources is
>> supported right now. If at some point the driver functionality is
>> expanded the bindings can be easily extended with it.
> 
> What's the relationship between the LEDs and backlight? It's a backlight
> plus LEDs or just 4 identical channels.

it is just 4 identical channels, represented as leds, or in this case 1 
led. I still feel a bit weird about this representation when there is 
also led-backlight. But it was requested to map it in this way.

>>
>> ---
>>   .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
>>   MAINTAINERS                                        |   5 +
>>   2 files changed, 112 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> new file mode 100644
>> index 000000000000..e83723224b07
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> @@ -0,0 +1,107 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Maxim max25014 backlight controller
>> +
>> +maintainers:
>> +  - Maud Spierings <maudspierings@gocontroll.com>
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - maxim,max25014
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  "#address-cells":
>> +    const: 1
>> +
>> +  "#size-cells":
>> +    const: 0
>> +
>> +  enable-gpios:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  power-supply:
>> +    description: Regulator which controls the boost converter input rail.
>> +
>> +  pwms:
>> +    maxItems: 1
>> +
>> +  maxim,iset:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    maximum: 15
>> +    default: 11
>> +    description:
>> +      Value of the ISET field in the ISET register. This controls the current
>> +      scale of the outputs, a higher number means more current.
> 
> We have properties for setting the current (in uA). That can't work
> here?

please refer to [1] and [2].

Link: 
https://lore.kernel.org/all/5c5cf363-db5c-4d0b-902f-97c6ef06c08f@gocontroll.com/ 
[1]

Link: 
https://lore.kernel.org/all/20251009-overjoyed-unpopular-54f69e9bd82c@spud/ 
[2]

kind regards,
Maud

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Frank Li 2 months, 1 week ago

On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings via B4 Relay wrote:
> From: Maud Spierings <maudspierings@gocontroll.com>
>
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with integrated boost controller.
>
> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>
> ---
>
> In the current implementation the control registers for channel 1,
> control all channels. So only one led subnode with led-sources is
> supported right now. If at some point the driver functionality is
> expanded the bindings can be easily extended with it.
> ---
>  .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
>  MAINTAINERS                                        |   5 +
>  2 files changed, 112 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> new file mode 100644
> index 000000000000..e83723224b07
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> @@ -0,0 +1,107 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Maxim max25014 backlight controller
> +
> +maintainers:
> +  - Maud Spierings <maudspierings@gocontroll.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - maxim,max25014
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +  enable-gpios:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  power-supply:
> +    description: Regulator which controls the boost converter input rail.
> +
> +  pwms:
> +    maxItems: 1
> +
> +  maxim,iset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    maximum: 15
> +    default: 11
> +    description:
> +      Value of the ISET field in the ISET register. This controls the current
> +      scale of the outputs, a higher number means more current.
> +
> +  led@0:

define whole binding, allow 0-3. binding is not related with driver's
implement.

it'd better put unders leds.


> +    type: object
> +    description: Properties for a string of connected LEDs.
> +    $ref: common.yaml#
> +
> +    properties:
> +      reg:
> +        const: 0
> +
> +      led-sources:
> +        allOf:
> +          - minItems: 1
> +            maxItems: 4
> +            items:
> +              minimum: 0
> +              maximum: 3
> +            default: [0, 1, 2, 3]
> +
> +      default-brightness:
> +        minimum: 0
> +        maximum: 100
> +        default: 50
> +
> +    required:
> +      - reg
> +
> +    additionalProperties: false

unevaluatedProperties: false because ref to common.yaml

Frank

> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        backlight@6f {
> +            compatible = "maxim,max25014";
> +            reg = <0x6f>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +            enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
> +            interrupt-parent = <&gpio1>;
> +            interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
> +            power-supply = <&reg_backlight>;
> +            pwms = <&pwm1>;
> +            maxim,iset = <7>;
> +
> +            led@0 {
> +                reg = <0>;
> +                led-sources = <0 1 2 3>;
> +                default-brightness = <50>;
> +            };
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 58c7e3f678d8..606ce086f758 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15261,6 +15261,11 @@ F:	Documentation/userspace-api/media/drivers/max2175.rst
>  F:	drivers/media/i2c/max2175*
>  F:	include/uapi/linux/max2175.h
>
> +MAX25014 BACKLIGHT DRIVER
> +M:	Maud Spierings <maudspierings@gocontroll.com>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> +
>  MAX31335 RTC DRIVER
>  M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
>  L:	linux-rtc@vger.kernel.org
>
> --
> 2.52.0
>
>

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Maud Spierings 2 months, 1 week ago

On 12/1/25 17:52, Frank Li wrote:
> On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings via B4 Relay wrote:
>> From: Maud Spierings <maudspierings@gocontroll.com>
>>
>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>> with integrated boost controller.
>>
>> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>>
>> ---
>>
>> In the current implementation the control registers for channel 1,
>> control all channels. So only one led subnode with led-sources is
>> supported right now. If at some point the driver functionality is
>> expanded the bindings can be easily extended with it.
>> ---
>>   .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
>>   MAINTAINERS                                        |   5 +
>>   2 files changed, 112 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> new file mode 100644
>> index 000000000000..e83723224b07
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> @@ -0,0 +1,107 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Maxim max25014 backlight controller
>> +
>> +maintainers:
>> +  - Maud Spierings <maudspierings@gocontroll.com>
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - maxim,max25014
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  "#address-cells":
>> +    const: 1
>> +
>> +  "#size-cells":
>> +    const: 0
>> +
>> +  enable-gpios:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  power-supply:
>> +    description: Regulator which controls the boost converter input rail.
>> +
>> +  pwms:
>> +    maxItems: 1
>> +
>> +  maxim,iset:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    maximum: 15
>> +    default: 11
>> +    description:
>> +      Value of the ISET field in the ISET register. This controls the current
>> +      scale of the outputs, a higher number means more current.
>> +
>> +  led@0:
> 
> define whole binding, allow 0-3. binding is not related with driver's
> implement.
> 
> it'd better put unders leds.
>

so like:

backlight: backlight@6f {
	compatible = "maxim,max25014";
	reg = <0x6f>;
	enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_backlight>;
	maxim,iset = <7>;

	leds {
		#address-cells = <1>;
		#size-cells = <0>;

		led@0 {
			reg = <0>;
			led-sources = <0 1 2>;
			default-brightness = <50>;
		};

		optional led@#....
	};
};

right?

Kind regards,
Maud

> 
>> +    type: object
>> +    description: Properties for a string of connected LEDs.
>> +    $ref: common.yaml#
>> +
>> +    properties:
>> +      reg:
>> +        const: 0
>> +
>> +      led-sources:
>> +        allOf:
>> +          - minItems: 1
>> +            maxItems: 4
>> +            items:
>> +              minimum: 0
>> +              maximum: 3
>> +            default: [0, 1, 2, 3]
>> +
>> +      default-brightness:
>> +        minimum: 0
>> +        maximum: 100
>> +        default: 50
>> +
>> +    required:
>> +      - reg
>> +
>> +    additionalProperties: false
> 
> unevaluatedProperties: false because ref to common.yaml
> 
> Frank
>

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Frank Li 2 months, 1 week ago

On Tue, Dec 02, 2025 at 08:46:21AM +0100, Maud Spierings wrote:
> On 12/1/25 17:52, Frank Li wrote:
> > On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings via B4 Relay wrote:
> > > From: Maud Spierings <maudspierings@gocontroll.com>
> > >
> > > The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> > > with integrated boost controller.
> > >
> > > Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
> > >
> > > ---
> > >
> > > In the current implementation the control registers for channel 1,
> > > control all channels. So only one led subnode with led-sources is
> > > supported right now. If at some point the driver functionality is
> > > expanded the bindings can be easily extended with it.
> > > ---
> > >   .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
> > >   MAINTAINERS                                        |   5 +
> > >   2 files changed, 112 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> > > new file mode 100644
> > > index 000000000000..e83723224b07
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> > > @@ -0,0 +1,107 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Maxim max25014 backlight controller
> > > +
> > > +maintainers:
> > > +  - Maud Spierings <maudspierings@gocontroll.com>
> > > +
> > > +properties:
> > > +  compatible:
> > > +    enum:
> > > +      - maxim,max25014
> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  "#address-cells":
> > > +    const: 1
> > > +
> > > +  "#size-cells":
> > > +    const: 0
> > > +
> > > +  enable-gpios:
> > > +    maxItems: 1
> > > +
> > > +  interrupts:
> > > +    maxItems: 1
> > > +
> > > +  power-supply:
> > > +    description: Regulator which controls the boost converter input rail.
> > > +
> > > +  pwms:
> > > +    maxItems: 1
> > > +
> > > +  maxim,iset:
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +    maximum: 15
> > > +    default: 11
> > > +    description:
> > > +      Value of the ISET field in the ISET register. This controls the current
> > > +      scale of the outputs, a higher number means more current.
> > > +
> > > +  led@0:
> >
> > define whole binding, allow 0-3. binding is not related with driver's
> > implement.
> >
> > it'd better put unders leds.
> >
>
> so like:
>
> backlight: backlight@6f {
> 	compatible = "maxim,max25014";
> 	reg = <0x6f>;
> 	enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
> 	pinctrl-names = "default";
> 	pinctrl-0 = <&pinctrl_backlight>;
> 	maxim,iset = <7>;
>
> 	leds {
> 		#address-cells = <1>;
> 		#size-cells = <0>;
>
> 		led@0 {
> 			reg = <0>;
> 			led-sources = <0 1 2>;
> 			default-brightness = <50>;
> 		};
>
> 		optional led@#....
> 	};
> };
>
> right?

yes.

>
> Kind regards,
> Maud
>
> >
> > > +    type: object
> > > +    description: Properties for a string of connected LEDs.
> > > +    $ref: common.yaml#
> > > +
> > > +    properties:
> > > +      reg:
> > > +        const: 0
> > > +
> > > +      led-sources:
> > > +        allOf:
> > > +          - minItems: 1
> > > +            maxItems: 4
> > > +            items:
> > > +              minimum: 0
> > > +              maximum: 3
> > > +            default: [0, 1, 2, 3]
> > > +
> > > +      default-brightness:
> > > +        minimum: 0
> > > +        maximum: 100
> > > +        default: 50
> > > +
> > > +    required:
> > > +      - reg
> > > +
> > > +    additionalProperties: false
> >
> > unevaluatedProperties: false because ref to common.yaml
> >
> > Frank
> >
>
>

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Maud Spierings 2 months ago

On 12/2/25 15:53, Frank Li wrote:
> On Tue, Dec 02, 2025 at 08:46:21AM +0100, Maud Spierings wrote:
>> On 12/1/25 17:52, Frank Li wrote:
>>> On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings via B4 Relay wrote:
>>>> From: Maud Spierings <maudspierings@gocontroll.com>
>>>>
>>>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>>>> with integrated boost controller.
>>>>
>>>> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>>>>
>>>> ---
>>>>
>>>> In the current implementation the control registers for channel 1,
>>>> control all channels. So only one led subnode with led-sources is
>>>> supported right now. If at some point the driver functionality is
>>>> expanded the bindings can be easily extended with it.
>>>> ---
>>>>    .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
>>>>    MAINTAINERS                                        |   5 +
>>>>    2 files changed, 112 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>>>> new file mode 100644
>>>> index 000000000000..e83723224b07
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>>>> @@ -0,0 +1,107 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Maxim max25014 backlight controller
>>>> +
>>>> +maintainers:
>>>> +  - Maud Spierings <maudspierings@gocontroll.com>
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    enum:
>>>> +      - maxim,max25014
>>>> +
>>>> +  reg:
>>>> +    maxItems: 1
>>>> +
>>>> +  "#address-cells":
>>>> +    const: 1
>>>> +
>>>> +  "#size-cells":
>>>> +    const: 0
>>>> +
>>>> +  enable-gpios:
>>>> +    maxItems: 1
>>>> +
>>>> +  interrupts:
>>>> +    maxItems: 1
>>>> +
>>>> +  power-supply:
>>>> +    description: Regulator which controls the boost converter input rail.
>>>> +
>>>> +  pwms:
>>>> +    maxItems: 1
>>>> +
>>>> +  maxim,iset:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>> +    maximum: 15
>>>> +    default: 11
>>>> +    description:
>>>> +      Value of the ISET field in the ISET register. This controls the current
>>>> +      scale of the outputs, a higher number means more current.
>>>> +
>>>> +  led@0:
>>>
>>> define whole binding, allow 0-3. binding is not related with driver's
>>> implement.
>>>
>>> it'd better put unders leds.
>>>
>>
>> so like:
>>
>> backlight: backlight@6f {
>> 	compatible = "maxim,max25014";
>> 	reg = <0x6f>;
>> 	enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
>> 	pinctrl-names = "default";
>> 	pinctrl-0 = <&pinctrl_backlight>;
>> 	maxim,iset = <7>;
>>
>> 	leds {
>> 		#address-cells = <1>;
>> 		#size-cells = <0>;
>>
>> 		led@0 {
>> 			reg = <0>;
>> 			led-sources = <0 1 2>;
>> 			default-brightness = <50>;
>> 		};
>>
>> 		optional led@#....
>> 	};
>> };
>>
>> right?
> 
> yes.
> 

I am feeling a bit weird about these led sub nodes, because it is not 
programmed as a led driver, it is programmed as a backlight. I am trying 
to figure out how this would be used later when the led strings are 
individually controllable.

it isn't possible to link the seperate strings to different displays 
because it is only one backlight device, so I don't seen any reason why 
it would ever be used in another way than what it is now, were all 
strings are programmed by one register.

The only way I can make sense of it is if instead I program this device 
as a led driver and then use the led_bl driver as the actual backlight.

Thats a pretty big step in a different direction, but then the led 
subnodes at least can be properly used I feel.

Kind regards,
Maud

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Rob Herring 2 months ago

On Mon, Dec 08, 2025 at 02:56:50PM +0100, Maud Spierings wrote:
> On 12/2/25 15:53, Frank Li wrote:
> > On Tue, Dec 02, 2025 at 08:46:21AM +0100, Maud Spierings wrote:
> > > On 12/1/25 17:52, Frank Li wrote:
> > > > On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings via B4 Relay wrote:
> > > > > From: Maud Spierings <maudspierings@gocontroll.com>
> > > > > 
> > > > > The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> > > > > with integrated boost controller.
> > > > > 
> > > > > Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
> > > > > 
> > > > > ---
> > > > > 
> > > > > In the current implementation the control registers for channel 1,
> > > > > control all channels. So only one led subnode with led-sources is
> > > > > supported right now. If at some point the driver functionality is
> > > > > expanded the bindings can be easily extended with it.
> > > > > ---
> > > > >    .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
> > > > >    MAINTAINERS                                        |   5 +
> > > > >    2 files changed, 112 insertions(+)
> > > > > 
> > > > > diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> > > > > new file mode 100644
> > > > > index 000000000000..e83723224b07
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> > > > > @@ -0,0 +1,107 @@
> > > > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > > > +%YAML 1.2
> > > > > +---
> > > > > +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
> > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > +
> > > > > +title: Maxim max25014 backlight controller
> > > > > +
> > > > > +maintainers:
> > > > > +  - Maud Spierings <maudspierings@gocontroll.com>
> > > > > +
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    enum:
> > > > > +      - maxim,max25014
> > > > > +
> > > > > +  reg:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  "#address-cells":
> > > > > +    const: 1
> > > > > +
> > > > > +  "#size-cells":
> > > > > +    const: 0
> > > > > +
> > > > > +  enable-gpios:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  interrupts:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  power-supply:
> > > > > +    description: Regulator which controls the boost converter input rail.
> > > > > +
> > > > > +  pwms:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  maxim,iset:
> > > > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > > > +    maximum: 15
> > > > > +    default: 11
> > > > > +    description:
> > > > > +      Value of the ISET field in the ISET register. This controls the current
> > > > > +      scale of the outputs, a higher number means more current.
> > > > > +
> > > > > +  led@0:
> > > > 
> > > > define whole binding, allow 0-3. binding is not related with driver's
> > > > implement.
> > > > 
> > > > it'd better put unders leds.
> > > > 
> > > 
> > > so like:
> > > 
> > > backlight: backlight@6f {
> > > 	compatible = "maxim,max25014";
> > > 	reg = <0x6f>;
> > > 	enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
> > > 	pinctrl-names = "default";
> > > 	pinctrl-0 = <&pinctrl_backlight>;
> > > 	maxim,iset = <7>;
> > > 
> > > 	leds {
> > > 		#address-cells = <1>;
> > > 		#size-cells = <0>;
> > > 
> > > 		led@0 {
> > > 			reg = <0>;
> > > 			led-sources = <0 1 2>;
> > > 			default-brightness = <50>;
> > > 		};
> > > 
> > > 		optional led@#....
> > > 	};
> > > };
> > > 
> > > right?
> > 
> > yes.
> > 
> 
> I am feeling a bit weird about these led sub nodes, because it is not
> programmed as a led driver, it is programmed as a backlight. I am trying to
> figure out how this would be used later when the led strings are
> individually controllable.
> 
> it isn't possible to link the seperate strings to different displays because
> it is only one backlight device, so I don't seen any reason why it would
> ever be used in another way than what it is now, were all strings are
> programmed by one register.
> 
> The only way I can make sense of it is if instead I program this device as a
> led driver and then use the led_bl driver as the actual backlight.
> 
> Thats a pretty big step in a different direction, but then the led subnodes
> at least can be properly used I feel.

If you don't have any use for anything other than driving a single 
backlight, then I'd just drop the led nodes completely.

Rob

Re: [PATCH v6 1/4] dt-bindings: backlight: Add max25014 support

Posted by Maud Spierings 1 month, 3 weeks ago

On 12/9/25 20:07, Rob Herring wrote:
> On Mon, Dec 08, 2025 at 02:56:50PM +0100, Maud Spierings wrote:
>> On 12/2/25 15:53, Frank Li wrote:
>>> On Tue, Dec 02, 2025 at 08:46:21AM +0100, Maud Spierings wrote:
>>>> On 12/1/25 17:52, Frank Li wrote:
>>>>> On Mon, Dec 01, 2025 at 12:53:20PM +0100, Maud Spierings via B4 Relay wrote:
>>>>>> From: Maud Spierings <maudspierings@gocontroll.com>
>>>>>>
>>>>>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>>>>>> with integrated boost controller.
>>>>>>
>>>>>> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>>>>>>
>>>>>> ---
>>>>>>
>>>>>> In the current implementation the control registers for channel 1,
>>>>>> control all channels. So only one led subnode with led-sources is
>>>>>> supported right now. If at some point the driver functionality is
>>>>>> expanded the bindings can be easily extended with it.
>>>>>> ---
>>>>>>     .../bindings/leds/backlight/maxim,max25014.yaml    | 107 +++++++++++++++++++++
>>>>>>     MAINTAINERS                                        |   5 +
>>>>>>     2 files changed, 112 insertions(+)
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>>>>>> new file mode 100644
>>>>>> index 000000000000..e83723224b07
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>>>>>> @@ -0,0 +1,107 @@
>>>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>>>>> +%YAML 1.2
>>>>>> +---
>>>>>> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>>> +
>>>>>> +title: Maxim max25014 backlight controller
>>>>>> +
>>>>>> +maintainers:
>>>>>> +  - Maud Spierings <maudspierings@gocontroll.com>
>>>>>> +
>>>>>> +properties:
>>>>>> +  compatible:
>>>>>> +    enum:
>>>>>> +      - maxim,max25014
>>>>>> +
>>>>>> +  reg:
>>>>>> +    maxItems: 1
>>>>>> +
>>>>>> +  "#address-cells":
>>>>>> +    const: 1
>>>>>> +
>>>>>> +  "#size-cells":
>>>>>> +    const: 0
>>>>>> +
>>>>>> +  enable-gpios:
>>>>>> +    maxItems: 1
>>>>>> +
>>>>>> +  interrupts:
>>>>>> +    maxItems: 1
>>>>>> +
>>>>>> +  power-supply:
>>>>>> +    description: Regulator which controls the boost converter input rail.
>>>>>> +
>>>>>> +  pwms:
>>>>>> +    maxItems: 1
>>>>>> +
>>>>>> +  maxim,iset:
>>>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>>>> +    maximum: 15
>>>>>> +    default: 11
>>>>>> +    description:
>>>>>> +      Value of the ISET field in the ISET register. This controls the current
>>>>>> +      scale of the outputs, a higher number means more current.
>>>>>> +
>>>>>> +  led@0:
>>>>>
>>>>> define whole binding, allow 0-3. binding is not related with driver's
>>>>> implement.
>>>>>
>>>>> it'd better put unders leds.
>>>>>
>>>>
>>>> so like:
>>>>
>>>> backlight: backlight@6f {
>>>> 	compatible = "maxim,max25014";
>>>> 	reg = <0x6f>;
>>>> 	enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
>>>> 	pinctrl-names = "default";
>>>> 	pinctrl-0 = <&pinctrl_backlight>;
>>>> 	maxim,iset = <7>;
>>>>
>>>> 	leds {
>>>> 		#address-cells = <1>;
>>>> 		#size-cells = <0>;
>>>>
>>>> 		led@0 {
>>>> 			reg = <0>;
>>>> 			led-sources = <0 1 2>;
>>>> 			default-brightness = <50>;
>>>> 		};
>>>>
>>>> 		optional led@#....
>>>> 	};
>>>> };
>>>>
>>>> right?
>>>
>>> yes.
>>>
>>
>> I am feeling a bit weird about these led sub nodes, because it is not
>> programmed as a led driver, it is programmed as a backlight. I am trying to
>> figure out how this would be used later when the led strings are
>> individually controllable.
>>
>> it isn't possible to link the seperate strings to different displays because
>> it is only one backlight device, so I don't seen any reason why it would
>> ever be used in another way than what it is now, were all strings are
>> programmed by one register.
>>
>> The only way I can make sense of it is if instead I program this device as a
>> led driver and then use the led_bl driver as the actual backlight.
>>
>> Thats a pretty big step in a different direction, but then the led subnodes
>> at least can be properly used I feel.
> 
> If you don't have any use for anything other than driving a single
> backlight, then I'd just drop the led nodes completely.

Theoretically with how the registers are laid out, it should be able to 
control 4 led strings individually. But as I said when I configure led 
string 1 it will also affect all the others seemingly. I am not sure if 
with some other configuration you can indeed do individual control.

Before I start converting stuff back to how it was several versions ago. 
Frank, do you agree with removing the led nodes in this case? I don't 
want to get stuck between two different paths.

Kind regards,
Maud

[PATCH v6 1/4] dt-bindings: backlight: Add max25014 support
[PATCH v6 2/4] backlight: add max25014atg backlight
[PATCH v6 3/4] arm64: dts: freescale: moduline-display-av101hdt-a10: add backlight
[PATCH v6 4/4] arm64: dts: freescale: moduline-display-av123z7m-n17: add backlight