On 09/10/2013 02:47 AM, Lars Poeschel wrote: > On Tuesday 10 September 2013 17:19:24, Mark Brown wrote: >> On Wed, Sep 04, 2013 at 02:16:36PM -0600, Stephen Warren wrote: >>> On 09/04/2013 03:05 AM, Lars Poeschel wrote: >>>> The driver that tries to use the GPIO requested by this patch before HAS >>>> to >>>> fail. This is exactly the intention of this patch. We don't want the >>>> GPIO to be requested any more, if it is used as an interrupt pin. >>> >>> That will break existing drivers. There are drivers that request the >>> same GPIO and IRQ. IIRC, the SDHCI CD (Card Detect) GPIO is requested >>> that way. >> >> Yes, plus input devices and audio jack detection among others. This >> pattern is very common if the GPIO is actually being used as a GPIO, an >> edge triggered interrupt is used to flag when something happens and the >> state is determined by reading the GPIO state (often with some >> debounce). > > And I say it again for those coming into the discussion late, like it has been > said many many times before: This patch does not break any of this drivers. > They simply request their GPIO from DT and turn it into an irq using > gpio_to_irq, request that irq on their behalf and use it as GPIO and IRQ in > parallel. At least this is not a problem. Doesn't this patch call gpio_request() on the GPIO first, and hence prevent the driver's own gpio_request() from succeeding, since the GPIO is already requested? If this is not a problem, it sounds like a bug in gpio_request() not ensuring mutual exclusion for the GPIO. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
