On 3/31/15, 4:43 AM, "Mika Westerberg" <mika.westerberg@xxxxxxxxxxxxxxx>
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>
Thanks Mika! Couple of nits below to help it read a little better.
>---
> 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..b68cfa8a6865 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 does also support function names for GPIOs in similar fashion than
>DT.
ACPI also supports function names for GPIOs in a similar fashion to DT.
>+The above DT example can be converted to corresponding ACPI version with
... to an equivalent ACPI description with
>+the help of _DSD (Device Specific Data) which was introduced in ACPI 5.1:
s/ which was/, /
--
Darren
>+
>+ 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
> -------------
>--
>2.1.4
>
>
--
Darren Hart
Intel Open Source Technology Center
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