Re: [PATCH] spi: orion: Allow specifying which HW CS to use with a GPIO CS

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Jan,

On Wed, Jan 24, 2018 at 6:56 PM, Jan Kundrát <jan.kundrat@xxxxxxxxx> wrote:
> On středa 24. ledna 2018 16:03:15 CET, Jan Kundrát wrote:
>>> Renesas MSIOF also requires driving a native chip select, cfr. commit
>>> b8761434bdec32fa ("spi: sh-msiof: Implement cs-gpios configuration").
>>
>> I'll take a look. It could be a candidate for some shared code, I suppose.
>
> Hi Gert, if I take your code from that commit almost as-is, probing of my
> SPI controller fails with errno -16 (that's EBUSY, right?). The GPIO pin
> that I want to use is defined as a gpio-hog in the DT.
>
> Is my DT correct? Should I define the GPIO pin as an output hog? IS your
> code supposed to deal with this?

Using a hog indeed marks it busy, as the hog is a user.

Why do you use a hog in the first place? Shouldn't the SPI driver configure
the GPIO, according to cs-gpios?

Before the advent of DT, the platform code was supposed to take care of that,
so this may be a too-literal conversion from platform code to DT.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
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                                -- Linus Torvalds
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