linux-next regression caused by "gpiolib: request the gpio before querying its direction"

[Thomas Petazzoni]

Hello,

On Thu, 31 Aug 2017 10:22:12 +0100, Russell King - ARM Linux wrote:

> What about hardware which you can configure for some alternate function
> but still monitor the pin via GPIO, even though it's not mux'd as GPIO.
> 
> For instance, you may have a timer block which can capture on both
> edges of an external event signal, which needs the pin to be muxed for
> that function.  However, you need to read the state of the pin, and
> that is only available through GPIO.  Muxing the pin to be a GPIO just
> because someone requests the GPIO is, imho, ill thought-out and breaks
> some use cases.
> 
> IMHO, the pinmux settings should always be specified in DT, and that's
> what we should be using everywhere, not doing broken backdoor games like
> "the gpio is being requested, it's obvious that we want this pin to be
> a gpio" - that really doesn't follow.

Agreed.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com