Re: [PATCH 4/5] spi: spi-gpio: Make optional chipselect handling more explicit

[Geert Uytterhoeven <geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>]

Hi Linus,

On Wed, Jan 3, 2018 at 9:58 AM, Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On Wed, Jan 3, 2018 at 9:21 AM, Geert Uytterhoeven <geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org> wrote:
>
>> Hmm, having two indicators for the same feature (spi_gpio->has_cs == true and
>> spi_gpio->cs_gpios[0] = NULL), and the need to keep them in sync in the
>> future, also complicates things.
>
> The patch does not do this.
>
> It removes the latter and adds the former. That is why it removes the
> assignment of NULL to cs_gpios[0].

So what is cs_gpios[0] if has_cs == true? Oh, it will point to unallocated
memory right after the structure...

See, that's the ambiguity of having two variables...
We do have NULL pointers and ERR_PTRs, so this ambiguity can (and IMHO
should) be avoided.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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