0d9a693cc8
With release of ACPI 5.1 and _DSD method we can finally name GPIOs (and other things as well) returned by _CRS. Previously we were only able to use integer index to find the corresponding GPIO, which is pretty error prone if the order changes. With _DSD we can now query GPIOs using name instead of an integer index, like the below example shows: // Bluetooth device with reset and shutdown GPIOs Device (BTH) { Name (_HID, ...) Name (_CRS, ResourceTemplate () { GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionInputOnly, "\\_SB.GPO0", 0, ResourceConsumer) {15} GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionInputOnly, "\\_SB.GPO0", 0, ResourceConsumer) {27, 31} }) Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"reset-gpio", Package() {^BTH, 1, 1, 0 }}, Package () {"shutdown-gpio", Package() {^BTH, 0, 0, 0 }}, } }) } The format of the supported GPIO property is: Package () { "name", Package () { ref, index, pin, active_low }} ref - The device that has _CRS containing GpioIo()/GpioInt() resources, typically this is the device itself (BTH in our case). index - Index of the GpioIo()/GpioInt() resource in _CRS starting from zero. pin - Pin in the GpioIo()/GpioInt() resource. Typically this is zero. active_low - If 1 the GPIO is marked as active_low. Since ACPI GpioIo() resource does not have field saying whether it is active low or high, the "active_low" argument can be used here. Setting it to 1 marks the GPIO as active low. In our Bluetooth example the "reset-gpio" refers to the second GpioIo() resource, second pin in that resource with the GPIO number of 31. This patch implements necessary support to gpiolib for extracting GPIOs using _DSD device properties. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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.. | ||
apei | ||
debug.txt | ||
dsdt-override.txt | ||
enumeration.txt | ||
gpio-properties.txt | ||
initrd_table_override.txt | ||
method-customizing.txt | ||
method-tracing.txt | ||
namespace.txt | ||
scan_handlers.txt | ||
video_extension.txt |