Re: [PATCH] Input: gpio_keys: allocate pins

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On Fri, Oct 12, 2012 at 11:40 PM, Daniel Mack <zonque@xxxxxxxxx> wrote:

>> Because we wrote in Documentation/pinctrl.txt that if GPIO
>> and pin control handle the same lines, they should be
>> implemented in the gpio driver by calling out to pinctrl's
>> extern int pinctrl_request_gpio(unsigned gpio);
>> extern void pinctrl_free_gpio(unsigned gpio);
>> extern int pinctrl_gpio_direction_input(unsigned gpio);
>> extern int pinctrl_gpio_direction_output(unsigned gpio);
>
> Hmm. So how is a certain pin muxed to its GPIO function then?

By calling exactly the above functions from the GPIO
driver.

> And how
> can pullup/pulldown features be selected?

So as stated in:
"Drivers needing both pin control and GPIOs"

This can be done in several ways, but this way is one option
indeed, so that is a valid reason for having this pinctrl here.

Is biasing what you need to do?

> I admittedly might lack some background here, and if there's better
> solution to what I want to do, I'd be happy to hear about it :)

Sure, no problem we've even tried to document it :-)

All I really want is that platforms have a clear idea about
how and where the pins will be handled, and that if GPIO
and pinctrl handle the same lines, they need to interact.

Yours,
Linus Walleij
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