[alsa-devel] [PATCH 1/3] irq: If an IRQ is a GPIO, request and configure it
broonie at opensource.wolfsonmicro.com
Fri Aug 5 07:35:11 CEST 2011
On Thu, Aug 04, 2011 at 08:53:34PM -0700, Stephen Warren wrote:
> Well, things break. This is essentially the problem I was describing in
> the PATCH 0 email, just with a slightly different motivation.
There's a bunch of existing code using that idiom.
> I suppose that an alternative here would be to simply ignore any errors
> from gpio_request. This might have the benefit of removing the need for
> the other two patches I posted in the series. However, it seems a little
> dirty; one benefit of the IRQ code calling gpio_request and honoring
> errors would be to detect when some completely unrelated code had a bug
> and had called gpio_request on the GPIO before. Such detection would be
> non-existent if we don't error out on gpio_request. Perhaps some mechanism
> is needed to indicate that the driver has explicitly already called
> gpio_request for a legitimate shared purpose, and only then ignore
But it's not a bug to use a GPIO as an IRQ source, otherwise we wouldn't
have gpio_to_irq() in the first place. Feels like we need a backchannel
between gpiolib and the IRQ code to do this. Or perhaps the drivers
that implement this should be taking care of setting up the GPIO mode?
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