# Re: \[PATCH 1/2\] dt-bindings: leds: backlight: add Kinetic KTD3137

- From: Daniel Thompson \<danielt@kernel.org\>
- Date: 2026-11-03 14:42:09 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2026/11/17853431
- Thread: https://ratatoskr.run/dri-devel/2026/11/17847320/t.md

```text
On Tue, Nov 03, 2026 at 02:34:02PM +0000, Roman Vivchar wrote:
> Hi Daniel,
>
> On Tuesday, November 3rd, 2026 at 4:05 PM, Daniel Thompson [ref] wrote:
> > On Mon, Nov 02, 2026 at 09:58:48PM +0200, Roman Vivchar via B4 Relay wrote:
> > > +  led-max-microamp:
> > > +    minimum: 5000
> > > +    maximum: 29800
> > > +    default: 20200
> > > +
> > > +  vin-supply: true
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - vin-supply
> >
> > Why is vin-supply required?
> >
>
> The chip cannot function without VIN power supply. Even if it's on the
> always-on power rail on certain board, there's always a chance it might be
> accidentally left disabled on the other. It's better to document supply in
> the bindings as far as I understand.

You haven't just documented the binding, you have also made the property
mandatory by adding it to required.

So what I am asking is why is this property listed as required. You
didn't implement the driver in a way that makes the supply mandatory.


Daniel.
```