On Fri, Oct 24, 2014 at 2:16 PM, Mika Westerberg <mika.westerb...@linux.intel.com> wrote:
> The GPIO resources (GpioIo/GpioInt) used in ACPI contain a GPIO number > which is relative to the hardware GPIO controller. Typically this number > can be translated directly to Linux GPIO number because the mapping is > pretty much 1:1. > > However, when the GPIO driver is using pins exported by a pin controller > driver via set of GPIO ranges, the mapping might not be 1:1 anymore and > direct translation does not work. > > In such cases we need to translate the ACPI GPIO number to be suitable for > the GPIO controller driver in question by checking all the pin controller > GPIO ranges under the given device and using those to get the proper GPIO > number. > > Signed-off-by: Mika Westerberg <mika.westerb...@linux.intel.com> I'm not sure what this patch does so I try to rely on you guys here. I would strongly like to have Rafael's ACK before proceeding. Trying to get the GPIO offsets to map 1:1 to Linux GPIO numbers is something that should be avoided since we want to get rid of the GPIO number space altogether. GPIO chips should try to register with .base = -1 so that the gpiolib just assigns some random GPIO numbers to the lines. What does actually exist? - GPIO offsets for a certain gpio_chip 0..N - Pin offsets for a certain pin controller 0..N GPIO ranges are for translating between these two. But I have a vague idea that there is something like a numberspace concept inside ACPI as well, and that is all magic to me... mixing that into this is a bit scary to me. > +#ifdef CONFIG_PINCTRL > +/** > + * acpi_gpiochip_pin_to_gpio_offset() - translates ACPI GPIO to Linux GPIO > + * @chip: GPIO chip > + * @pin: ACPI GPIO pin number from GpioIo/GpioInt resource So I guess I'm curious about this Gpiolo/GpioInt resource number space... Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
