Re: [PATCH 1/2] dt-bindings: display: Add Sharp Memory LCD bindings

From: Alex Lanzano
Date: Sun Jul 28 2024 - 10:52:45 EST


On Sun, Jul 28, 2024 at 04:43:42PM GMT, Krzysztof Kozlowski wrote:
> On 28/07/2024 14:56, Alex Lanzano wrote:
> >>>>> +
> >>>>> + spi-cs-high: true
> >>>>
> >>>> You can drop it.
> >>>>
> >>>
> >>> This is a required property in order for the display to function correctly.
> >>> But I have no issues removing it if there's a better place to document it.
> >>
> >> The sharp LCD device or the board (e.g. via some inversion)?
> >>
> >
> > The sharp LCD device itself.
> >
> > https://cdn.sparkfun.com/assets/d/e/8/9/7/LS013B7DH03_datasheet.pdf
> > Page 16 of the PDF below shows the timing chart for it if interested
>
> OK, so you enforce chip select as always high and then someone comes
> with a board which has a inversion and expect the SoC to drive it low,
> as usually? In such system this would not work, would it?
>
> IOW, I think this is the first case where you require specific CS high
> and this should make you think why...

Ahh I see what you mean! I'll remove it.

Best regard,
Alex