On Fri, Aug 08, 2014 at 02:36:02PM +0200, Linus Walleij wrote: > On Thu, Jul 24, 2014 at 5:51 PM, Tomasz Nowicki > <tomasz.nowicki@xxxxxxxxxx> wrote: > > > GPIO signaled events is quite new thing in Linux kernel. > > AFAIK, there are not many board which can take advantage of it. > > However, GPIO events are very useful feature during work on ACPI > > subsystems. > > Overall this seems like a pretty nice debug feature. > > > This commit emulates GPIO h/w behaviour and consists on read/write > > operation to debugfs file. GPIO device instance is still required in DSDT > > table along with _AEI resources and event methods. > > > > Reading from file provides pin to GPIO device map e.g. : > > $ cat /sys/kernel/debug/acpi/gpio_event > > GPIO device name: /__SB.GPI0 > > Available GPIO pin map: > > /__SB.GPI0 <-> pin 0x100 > > > > Based on that, user can trigger method corresponding to device pin number: > > $ echo "/__SB.GPI0 0x100" > /sys/kernel/debug/acpi/gpio_event > > I need input from Rafael and Mika as to whether this is a > good interface. Maybe it would make sense to move this into drivers/gpio/gpiolib-acpi.c and hide it behind some Kconfig entry? Since you already need to have DSDT/SSDT table for this to provide the GPIO device, _AEI and the event methods, I would rather make it so that acpi_gpiochip_request_interrupt() will add debugfs entry for each GPIO it finds in _AEI, like: /sys/kernel/debug/acpi/events/<GPIO DEVICE>/n And you could trigger it by writing '1' or something like that to that file. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
