On Fri, Nov 9, 2012 at 2:11 PM, Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> wrote: > On 11/08/2012 09:38 PM, Mika Westerberg wrote: > ... > >>>> +#include<linux/errno.h> >>>> +#include<linux/gpio.h> >>>> +#include<linux/module.h> >>>> +#include<linux/acpi_gpio.h> >>>> +#include<linux/acpi.h> >>>> + >>>> +static int acpi_gpiochip_find(struct gpio_chip *gc, void *data) >>>> +{ >>>> + acpi_handle handle = data; >>>> + acpi_handle gc_handle; >>>> + >>>> + if (!gc->dev) >>>> + return false; >>>> + >>>> + gc_handle = gc->dev->acpi_handle; >>>> + if (!gc_handle) >>>> + return false; >>> >>> >>> This test is redundant with the next one... unless 'handle' is also NULL >>> :-) >>> >>> Is it at all possible for multiple gpiochips to be used for a single >>> ACPI gpio controller node? Such as if the gpio controller has multiple >>> banks that should be controlled separately? If so then this won't be >>> sufficient. I've got the same issue with DT support where the find >>> function needs to also check if the pin is provided by that specific >>> gpiochip. >> >> >> AFAIK no but I'll let Mathias to answer that as he knows this better. > > > I'm interpreting it the same way as Mika, max one actual controller per ACPI > device node > > The path (called ResourceSource in ACPI5 specs) in GpioIO/GpioInt resources > is a "string which uniquely identifies the GPIO controller referred to by > this descriptor." The pin number is zero based controller relative. > > The ACPI device controller node includes all other resources needed by the > controller driver (ioport/mem base, range, interrupt, and Hardware ID used > to pair with a driver) > > Checked a board with two identical gpio controllers on it and it had two > separate ACPI device node entries. (with only different io address base and > interrupt resources) That's not really the situation that I'm thinking about. What I mean is for a gpio controller that is more convenient for Linux to support using multiple gpiochips (Linux internal detail), even though there it is described with a single ACPI node. g. -- 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