On Wednesday, April 01, 2015 11:13:16 AM Mika Westerberg wrote:
> With ACPI 5.1 _DSD (Device Specific Data) it is now possible to name
> functions just like Device Tree is doing. Make sure that the documentation
> mentions _DSD as the recommended way to describe GPIOs in ACPI systems.
>
> Reported-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> v2: Corrected text according what Darren suggested
>
> Documentation/gpio/board.txt | 41 +++++++++++++++++++++++++++++++++++++----
> 1 file changed, 37 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt
> index 8b35f51fe7b6..b80606de545a 100644
> --- a/Documentation/gpio/board.txt
> +++ b/Documentation/gpio/board.txt
> @@ -50,10 +50,43 @@ gpiod_is_active_low(power) will be true).
>
> ACPI
> ----
> -ACPI does not support function names for GPIOs. Therefore, only the "idx"
> -argument of gpiod_get_index() is useful to discriminate between GPIOs assigned
> -to a device. The "con_id" argument can still be set for debugging purposes (it
> -will appear under error messages as well as debug and sysfs nodes).
> +ACPI also supports function names for GPIOs in a similar fashion to DT.
> +The above DT example can be converted to an equivalent ACPI description
> +with the help of _DSD (Device Specific Data), introduced in ACPI 5.1:
> +
> + Device (FOO) {
> + Name (_CRS, ResourceTemplate () {
> + GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
> + "\\_SB.GPI0") {15} // red
> + GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
> + "\\_SB.GPI0") {16} // green
> + GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
> + "\\_SB.GPI0") {17} // blue
> + GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
> + "\\_SB.GPI0") {1} // power
> + })
> +
> + Name (_DSD, Package () {
> + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> + Package () {
> + Package () {
> + "led-gpios",
> + Package () {
> + ^FOO, 0, 0, 1,
> + ^FOO, 1, 0, 1,
> + ^FOO, 2, 0, 1,
> + }
> + },
> + Package () {
> + "power-gpios",
> + Package () {^FOO, 3, 0, 0},
> + },
> + }
> + })
> + }
> +
> +For more information about the ACPI GPIO bindings see
> +Documentation/acpi/gpio-properties.txt.
>
> Platform Data
> -------------
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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