Re: [RFC PATCH 02/16] dt-bindings: display: rockchip: Add EBC binding

Andreas Kemnade
2022-04-14T08:16:34Z

Hi Samuel,

for comparison, here is my submission for the IMX EPDC bindings:

https://lore.kernel.org/linux-devicetree/20220206080016.796556-2-andreas@kemnade.info/

On Wed, 13 Apr 2022 17:19:02 -0500
Samuel Holland <samuel@sholland.org> wrote:

[...]
we have sy7636a driver in kernel which should be suitable for powering a EPD
and temperature measurement. So I would expect that to be
> + io-channels:
> + maxItems: 1
> + description: I/O channel for panel temperature measurement
> +
so how would I reference the hwmon/thermal(-zone) of the sy7636a here?

> + panel-supply:
> + description: Regulator supplying the panel's logic voltage
> +
> + power-domains:
> + maxItems: 1
> +
> + vcom-supply:
> + description: Regulator supplying the panel's compensation voltage
> +
> + vdrive-supply:
> + description: Regulator supplying the panel's gate and source drivers
> +
SY7636a has only one logical regulator in kernel for for the latter two.

If we have a separate panel node, than maybe these regulators should go
there as they belong to the panel as they are powering the panel and
not the EBC.

> + port:
> + $ref: /schemas/graph.yaml#/properties/port
> + description: OF graph port for the attached display panel
> +
In my approach for the IMX EPDC, (I will send a better commented one
soon) I have no separate subnode to avoid messing with additional
display parameters. Not sure what is really better here.

> +required:
> + - compatible
> + - reg
> + - interrupts
> + - clocks
> + - clock-names
> + - resets
> + - reset-names
> + - power-domains
> + - panel-supply
> + - vcom-supply
> + - vdrive-supply

If things differ how the different phyiscally existing regulators are
mapped into logical ones (even the vdrive supply is still a bunch of
physical regulators mapped into one logical one), then not everything
can be required.

Regards,
Andreas