Messages in this thread | | | Date | Thu, 22 Aug 2013 15:10:53 -0600 | From | Stephen Warren <> | Subject | Re: [PATCH v2] gpio: interrupt consistency check for OF GPIO IRQs |
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On 08/21/2013 05:36 PM, Linus Walleij wrote: > On Thu, Aug 22, 2013 at 1:10 AM, Stephen Warren <swarren@wwwdotorg.org> wrote: > [Me] >>>> check if these in turn reference the interrupt-controller, and >>>> if they do, loop over the interrupts used by that child and >>>> perform gpio_request() and gpio_direction_input() on these, >>>> making them unreachable from the GPIO side. >> >> What about bindings that require a GPIO to be specified, yet don't allow >> an IRQ to be specified, and the driver internally does perform >> gpio_to_irq() on it? I don't think one can detect that case. > > This is still allowed. Consumers that prefer to have a GPIO > passed and convert it to IRQ by that call can still do so, > they will know what they're doing and will not cause the > double-command situation that we're trying to solve.
Why not? There are certainly drivers in the kernel which request a GPIO as both a GPIO and as an (dual-edge) interrupt, so that they can read the GPIO input whenever the IRQ goes off, in order to determine the pin state. This is safer against high-latency or lost interrupts.
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