Re: [RFC gpio/for-next 2/2] gpio: gpio-mux-input: add generic gpio input multiplexer

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Fri, Mar 26, 2021 at 12:32 PM Mauri Sandberg <sandberg@xxxxxxxxxxxxx> wrote:
> > From: Drew Fustini <drew@xxxxxxxxxxxxxxx>
> > Sent: Fri Mar 26 07:59:44 CET 2021

...

> > This does not apply to mainline. I've added it manually to my
> > drivers/gpio/Makefile but something to fix in v2.
>
> I was developing against gpio tree's [1] 'for-next' branch but should I go against mainline?

It's a Bart's tree nowadays [3], gpio/for-next branch.

> > > +   ret = gpiod_get_value(mux->mux_pin);
> >
> > I'm not too familiar with how mux_control works but does there need to
> > be locking here?
> >
> > Or is not possible for mux_pin to change to another offset before if
> > gpiod_get_value() if gpio_mux_input_get_value() runs concurrently?
>
> According to mux documentation [2] successfully selecting a state locks the mux
> until it is deselected. So I reckon no extra locking is needed.

...

> [1] https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/mux/core.c#n322

[3]: https://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git/

-- 
With Best Regards,
Andy Shevchenko