Re: [RFC PATCH 1/6] dt-bindings: display: imx: Add EPDC

Andreas Kemnade
2022-02-17T11:31:40Z

On Thu, 17 Feb 2022 10:21:15 +0100
Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> wrote:

> On 06/02/2022 09:00, Andreas Kemnade wrote:
> > Add a binding for the Electrophoretic Display Controller found at least
> > in the i.MX6.
> > The timing subnode is directly here to avoid having display parameters
> > spread all over the plate.
> >
> > Supplies are organized the same way as in the fbdev driver in the
> > NXP/Freescale kernel forks. The regulators used for that purpose,
> > like the TPS65185, the SY7636A and MAX17135 have typically a single bit to
> > start a bunch of regulators of higher or negative voltage with a
> > well-defined timing. VCOM can be handled separately, but can also be
> > incorporated into that single bit.
> >
> > Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> > ---
> > .../bindings/display/imx/fsl,mxc-epdc.yaml | 159 ++++++++++++++++++
> > 1 file changed, 159 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/display/imx/fsl,mxc-epdc.yaml
> >
[..]

> > +
> > + DISPLAY-supply:
> > + description:
> > + A couple of +/- voltages automatically powered on in a defintive order
>
> Typo, definitive?
>
yes, of course.

> > +
> > + VCOM-supply:
> > + description: compensation voltage
> > +
> > + V3P3-supply:
>
> All of supplies names - lowercase.
>
> > + description: V3P3 supply
> > +
> > + epd-thermal-zone:
> > + description:
> > + Zone to get temperature of the EPD from, practically ambient temperature.
>
> Is it a phandle?
>
a string used in
of_property_read_string(priv->drm.dev->of_node,
"epd-thermal-zone", &thermal);
if (thermal) {
priv->thermal = thermal_zone_get_zone_by_name(thermal);
if (IS_ERR(priv->thermal))
return dev_err_probe(priv->drm.dev, PTR_ERR(priv->thermal),
"unable to get thermal");
}

[...]
> > +examples:
> > + - |
> > + #include <dt-bindings/clock/imx6sl-clock.h>
> > + #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +
> > + epdc: epdc@20f4000 {
>
> Generic node name, e.g. display-controller
>
hmm, does IHMO not make too much sense here. E.g. in the imx6sll.dtsi
we have lcd-controller next to it. So having epd-controller? But that
is exactly what epdc stands for.

Regards,
Andreas