Re: [PATCH 5/9] dt-bindings: input: touchscreen: goodix: Document vcc-supply property

From: Jagan Teki
Date: Wed Dec 05 2018 - 14:56:58 EST


On Mon, Dec 3, 2018 at 4:11 PM Chen-Yu Tsai <wens@xxxxxxxx> wrote:
>
> On Mon, Dec 3, 2018 at 6:16 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > vcc-supply property is need for some Goodix CTP controller like GT5663
> > where 3.3V external pull-up regulator connected via controller VCC pin.
>
> "External pull-up regulator" sounds fishy. Chips have power supply
> pins, either combined, or separate rails for analog, digital, and I/O.
> For Goodix chips these are AVDD28, AVDD22, DVDD12, amd VDDIO. The name
> and description you provide match none of these.

We have vcc pin in the connector to supply vcc-ctp, but indeed it is
AVDD28 supply as per the reference schematic design[1] Page 23. Host
interface has AVDD pin which is connected to ADVDD28 on goodix chip,
so I can name this as avdd28-supply. is that OK?

[1] https://www.crystalfontz.com/controllers/GOODIX/GT5663/459/