From: Thierry Reding <redacted>

Tegra186 and later have some top-level controls for wake events in the
power management controller (PMC). In order to enable the system to wake
up from low power states, additional registers in the PMC need to be
programmed. Add a wakeup-parent property to establish this relationship
between the GPIO controller and the PMC.

Signed-off-by: Thierry Reding <redacted>
---
  .../devicetree/bindings/gpio/nvidia,tegra186-gpio.txt      | 7 +++++++
  1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/nvidia,tegra186-gpio.txt b/Documentation/devicetree/bindings/gpio/nvidia,tegra186-gpio.txt
index adff16c71d21..cbb51a8990c3 100644
--- a/Documentation/devicetree/bindings/gpio/nvidia,tegra186-gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/nvidia,tegra186-gpio.txt

@@ -127,6 +127,11 @@ Required properties:
              - 8: Active low level-sensitive.
              Valid combinations are 1, 2, 3, 4, 8.
  
+Optional properties:
+- wake-parent

+    A phandle to the Power Management Controller (PMC) that contains top-
+    level controls to enable the wake-up capabilities of some GPIOs.
+
  Example:
  
  #include <dt-bindings/interrupt-controller/irq.h>

@@ -148,6 +153,7 @@ gpio@2200000 {
  	#gpio-cells = <2>;
  	interrupt-controller;
  	#interrupt-cells = <2>;
+	wakeup-parent = <&pmc>;
  };
  
  gpio@c2f0000 {

@@ -162,4 +168,5 @@ gpio@c2f0000 {
  	#gpio-cells = <2>;
  	interrupt-controller;
  	#interrupt-cells = <2>;
+	wakeup-parent = <&pmc>;
  };