Re: [PATCH 2/2] ARM: dts: imx6qdl: tqma6: minor fixes
From: Fabio Estevam
Date: Thu Aug 27 2020 - 17:28:15 EST
Hi Matthias,
(Your mailer is messing the threading.)
On Thu, Aug 27, 2020 at 4:31 AM Matthias Schiffer
<matthias.schiffer@xxxxxxxxxxxxxxx> wrote:
> Ah, I see.
>
> Nevertheless, hardware that uses the native chipselects of newer chips
> exists (for example our TQ-Systems starterkit mainboards, the DTS of
> which we're currently preparing for mainline submission). Shouldn't
> num-cs be set for boards (or SoM DTSI) where not all CS pins of the SoC
> are usable?
>
> In any case, my original question was about the intended logic for
> num_chipselects for SPI drivers. My proposal was:
>
> - If num-cs is set, use that
> - If num-cs is unset, use the number of cs-gpios
> - If num-cs is unset and no cs-gpios are defined, use a driver-provided
> default
>
> How do other SPI controller drivers deal with this?
I think it would be better to discuss this in the spi mailing list
with Mark Brown and the dt maintainer, Rob Herring.