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

[Neil Armstrong]

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@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> > ---
> >   .../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@xxxxxxxxxx>
> > +
> > +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.