On 09/22/2013 08:40 AM, Javier Martinez Canillas wrote: > To use a GPIO pin as an interrupt line, two previous configurations > have to be made: > > a) Map the GPIO pin as an interrupt line into the Linux irq space > b) Enable the GPIO bank and configure the GPIO direction as input > > Most GPIO/IRQ chip drivers just create a mapping for every single > GPIO pin with irq_create_mapping() on .probe so users usually can > assume a) and only have to do b) by using the following sequence: > > gpio_request(gpio, "foo IRQ"); > gpio_direction_input(gpio); > > and then request a IRQ with: > > irq = gpio_to_irq(gpio); > request_irq(irq, ...); > > Some drivers know that their IRQ line is being driven by a GPIO > and use a similar sequence as the described above but others are > not aware or don't care wether their IRQ is a real line from an > interrupt controller or a GPIO pin acting as an IRQ. > ...
I think that explanation is a bit like retro-actively implying that drivers /should/ be aware of whether their IRQ is a GPIO or not, and should be acting differently. However, they should not. I would much rather see a simpler patch description along the lines of: The OMAP GPIO controller HW requires that a pin be configured in GPIO mode in order to operate as an interrupt input. Since drivers should not be aware of whether an interrupt pin is also a GPIO or not, the HW should be fully configured/enabled as an IRQ if a driver solely uses IRQ APIs such as request_irq, and never calls any GPIO-related APIs. As such, add the missing HW setup to the OMAP GPIO controller's irq_chip driver. The code change looks like it does what I would expect though. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
