From 863981e96738983919de841ec669e157e6bdaeb0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Sun, 11 Sep 2016 04:34:46 -0300 Subject: Linux-libre 4.7.1-gnu --- .../bindings/power/reset/gpio-poweroff.txt | 36 ++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt (limited to 'Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt') diff --git a/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt b/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt new file mode 100644 index 000000000..d4eab9227 --- /dev/null +++ b/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt @@ -0,0 +1,36 @@ +Driver a GPIO line that can be used to turn the power off. + +The driver supports both level triggered and edge triggered power off. +At driver load time, the driver will request the given gpio line and +install a pm_power_off handler. If the optional properties 'input' is +not found, the GPIO line will be driven in the inactive +state. Otherwise its configured as an input. + +When the pm_power_off is called, the gpio is configured as an output, +and drive active, so triggering a level triggered power off +condition. This will also cause an inactive->active edge condition, so +triggering positive edge triggered power off. After a delay of 100ms, +the GPIO is set to inactive, thus causing an active->inactive edge, +triggering negative edge triggered power off. After another 100ms +delay the GPIO is driver active again. If the power is still on and +the CPU still running after a 3000ms delay, a WARN_ON(1) is emitted. + +Required properties: +- compatible : should be "gpio-poweroff". +- gpios : The GPIO to set high/low, see "gpios property" in + Documentation/devicetree/bindings/gpio/gpio.txt. If the pin should be + low to power down the board set it to "Active Low", otherwise set + gpio to "Active High". + +Optional properties: +- input : Initially configure the GPIO line as an input. Only reconfigure + it to an output when the pm_power_off function is called. If this optional + property is not specified, the GPIO is initialized as an output in its + inactive state. + +Examples: + +gpio-poweroff { + compatible = "gpio-poweroff"; + gpios = <&gpio 4 0>; +}; -- cgit v1.2.3-54-g00ecf