Re: [PATCH v3 1/2] dt-bindings: leds: backlight: document the SY7758 6-channel High Efficiency LED Driver

[Neil Armstrong <neil.armstrong@linaro.org>]

On 5/29/26 12:07, Daniel Thompson wrote:
> On Tue, May 19, 2026 at 10:43:38AM +0200, Neil Armstrong wrote:
>> Document the Silergy SY7758 6-channel High Efficiency LED Driver
>> used for backlight brightness control.
>>
>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
>> ---
>>   .../bindings/leds/backlight/silergy,sy7758.yaml    | 53 ++++++++++++++++++++++
>>   1 file changed, 53 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/backlight/silergy,sy7758.yaml b/Documentation/devicetree/bindings/leds/backlight/silergy,sy7758.yaml
>> new file mode 100644
>> index 000000000000..80e978d691c2
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/backlight/silergy,sy7758.yaml
>> @@ -0,0 +1,53 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/backlight/silergy,sy7758.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Silergy SY7758 6-channel High Efficiency LED Driver
>> +
>> +maintainers:
>> +  - Neil Armstrong <neil.armstrong@linaro.org>
>> +
>> +description:
>> +  Silergy SY7758 is a high efficiency 6-channels LED backlight
>> +  driver with I2C brightness control.
>> +
>> +allOf:
>> +  - $ref: common.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    const: silergy,sy7758
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  vddio-supply: true
>> +
>> +  enable-gpios:
>> +    maxItems: 1
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - vddio-supply
> 
> Sorry for missing this in v2 but is vddio-supply really a required
> property?
> 
> It's unusual for supplies to be mandatory (and the it is not mandatory
> in the driver implementation).

This device is a little bit special, the VDDIO regulator is used to provide
power for the I/O via the enable input, so basically the enable gpio power
level is provided by VDDIO.

This is the recommended way from the datasheet, and I assume it will be used
like that on other platforms (if it exists...)

This is why it's mandatory and enabled first before setting the enable pin.

This should probably be a comment in the code.

Neil

> 
> 
> Daniel.