From 0d6c41cf801fd56b92f4359374667061d27a6472 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 29 Oct 2020 21:32:42 +0200 Subject: [PATCH] Documentation: firmware-guide: gpio-properties: active_low only for GpioIo() It appears that people may misinterpret active_low field in _DSD for GpioInt() resource. Add a paragraph to clarify this. Reported-by: Ricardo Ribalda Signed-off-by: Andy Shevchenko Reviewed-by: Mika Westerberg Reviewed-by: Ricardo Ribalda Signed-off-by: Rafael J. Wysocki --- Documentation/firmware-guide/acpi/gpio-properties.rst | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/firmware-guide/acpi/gpio-properties.rst b/Documentation/firmware-guide/acpi/gpio-properties.rst index e6e65ceb2ca1..370fe46c6af9 100644 --- a/Documentation/firmware-guide/acpi/gpio-properties.rst +++ b/Documentation/firmware-guide/acpi/gpio-properties.rst @@ -55,6 +55,9 @@ Since ACPI GpioIo() resource does not have a 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. +Note, active_low in _DSD does not make sense for GpioInt() resource and +must be 0. GpioInt() resource has its own means of defining it. + In our Bluetooth example the "reset-gpios" refers to the second GpioIo() resource, second pin in that resource with the GPIO number of 31.