Re: [PATCH 1/2] dt-bindings: backlight: Convert LP8860 into YAML format adding LP886x

[Andrew Davis <afd@ti.com>]

On 12/6/24 11:14 AM, Conor Dooley wrote:
> On Fri, Dec 06, 2024 at 06:07:12PM +0100, A. Sverdlin wrote:
>> From: Alexander Sverdlin <alexander.sverdlin@siemens.com>
>>
>> Add Texas Instruments' LP8864/LP8866 bindings into LP8860 converting them
>> into YAML format simultaneously. While here, drop the index of the "led"
>> subnode, this one is neither used nor mandated by the drivers. All the
>> *-cells properties are therefore not required.
> 

The index isn't needed, but we should still allow for multiple child
LED nodes. The usual way to do this is with node names led-0, led-1, etc..

See here for the usual patternProperties for that:

https://www.kernel.org/doc/Documentation/devicetree/bindings/leds/leds-pwm.yaml

> Are you sure this is a correct thing to do? The lp8860-q1 product link
> cites it as being a 4-channel device. Even if the kernel only ever
> supports it as a single-channel device, the binding should reflect what
> it is capable of doing.
> 

Agree, the driver today just checks the first child node, but it could
be extended for all 4 supported LED channels, and we shouldn't have
to change the binding for that new support.

Andrew

> Cheers,
> Conor.
> 
>>
>> Move the file into backlight directory because all of the LP886x drivers
>> are special backlight products.
>>
>> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
>> ---
>>   .../bindings/leds/backlight/ti,lp8860.yaml    | 86 +++++++++++++++++++
>>   .../devicetree/bindings/leds/leds-lp8860.txt  | 50 -----------
>>   2 files changed, 86 insertions(+), 50 deletions(-)
>>   create mode 100644 Documentation/devicetree/bindings/leds/backlight/ti,lp8860.yaml
>>   delete mode 100644 Documentation/devicetree/bindings/leds/leds-lp8860.txt
>>
>> diff --git a/Documentation/devicetree/bindings/leds/backlight/ti,lp8860.yaml b/Documentation/devicetree/bindings/leds/backlight/ti,lp8860.yaml
>> new file mode 100644
>> index 0000000000000..3ece2f6fc3f02
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/backlight/ti,lp8860.yaml
>> @@ -0,0 +1,86 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/backlight/ti,lp8860.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Texas Instruments - LP886x 4/6-Channel LED Driver family
>> +
>> +maintainers:
>> +  - Andrew Davis <afd@ti.com>
>> +  - Alexander Sverdlin <alexander.sverdlin@siemens.com>
>> +
>> +description: |
>> +  The LP8860-Q1 is an high-efficiency LED driver with boost controller.
>> +  It has 4 high-precision current sinks that can be controlled by a PWM input
>> +  signal, a SPI/I2C master, or both.
>> +
>> +  LP8866-Q1, LP8866S-Q1, LP8864-Q1, LP8864S-Q1 are newer products offering
>> +  similar functionality with 4/6 channels.
>> +
>> +  For more product information please see the links below:
>> +    https://www.ti.com/product/lp8860-q1
>> +    https://www.ti.com/product/LP8864-Q1
>> +    https://www.ti.com/product/LP8864S-Q1
>> +    https://www.ti.com/product/LP8866-Q1
>> +    https://www.ti.com/product/LP8866S-Q1
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - ti,lp8860
>> +      - ti,lp8864
>> +
>> +  reg:
>> +    maxItems: 1
>> +    description: I2C slave address
>> +
>> +  enable-gpios:
>> +    maxItems: 1
>> +    description: GPIO pin to enable (active high) / disable the device
>> +
>> +  vled-supply:
>> +    description: LED supply
>> +
>> +  led:
>> +    type: object
>> +    $ref: common.yaml#
>> +    properties:
>> +      function: true
>> +      color: true
>> +      label: true
>> +      linux,default-trigger: true
>> +
>> +    additionalProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - led
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +    #include <dt-bindings/leds/common.h>
>> +
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        led-controller@2d {
>> +            compatible = "ti,lp8860";
>> +            reg = <0x2d>;
>> +            enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
>> +            vled-supply = <&vbatt>;
>> +
>> +            led {
>> +                function = LED_FUNCTION_BACKLIGHT;
>> +                color = <LED_COLOR_ID_WHITE>;
>> +                linux,default-trigger = "backlight";
>> +            };
>> +        };
>> +    };
>> +
>> +...
>> diff --git a/Documentation/devicetree/bindings/leds/leds-lp8860.txt b/Documentation/devicetree/bindings/leds/leds-lp8860.txt
>> deleted file mode 100644
>> index 8bb25749a3da3..0000000000000
>> --- a/Documentation/devicetree/bindings/leds/leds-lp8860.txt
>> +++ /dev/null
>> @@ -1,50 +0,0 @@
>> -* Texas Instruments - lp8860 4-Channel LED Driver
>> -
>> -The LP8860-Q1 is an high-efficiency LED
>> -driver with boost controller. It has 4 high-precision
>> -current sinks that can be controlled by a PWM input
>> -signal, a SPI/I2C master, or both.
>> -
>> -Required properties:
>> -	- compatible :
>> -		"ti,lp8860"
>> -	- reg : I2C slave address
>> -	- #address-cells : 1
>> -	- #size-cells : 0
>> -
>> -Optional properties:
>> -	- enable-gpios : gpio pin to enable (active high)/disable the device.
>> -	- vled-supply : LED supply
>> -
>> -Required child properties:
>> -	- reg : 0
>> -
>> -Optional child properties:
>> -	- function : see Documentation/devicetree/bindings/leds/common.txt
>> -	- color : see Documentation/devicetree/bindings/leds/common.txt
>> -	- label : see Documentation/devicetree/bindings/leds/common.txt (deprecated)
>> -	- linux,default-trigger :
>> -	   see Documentation/devicetree/bindings/leds/common.txt
>> -
>> -Example:
>> -
>> -#include <dt-bindings/leds/common.h>
>> -
>> -led-controller@2d {
>> -	compatible = "ti,lp8860";
>> -	#address-cells = <1>;
>> -	#size-cells = <0>;
>> -	reg = <0x2d>;
>> -	enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
>> -	vled-supply = <&vbatt>;
>> -
>> -	led@0 {
>> -		reg = <0>;
>> -		function = LED_FUNCTION_BACKLIGHT;
>> -		color = <LED_COLOR_ID_WHITE>;
>> -		linux,default-trigger = "backlight";
>> -	};
>> -}
>> -
>> -For more product information please see the link below:
>> -https://www.ti.com/product/lp8860-q1
>> -- 
>> 2.47.1
>>