Re: [PATCH 1/3] gpio: Add simple poweroff-gpio driver

On 11/11/2012 09:21 AM, Andrew Lunn wrote:

From: Jamie Lentin <jm-Pj/HzkgeCk7QXOPxS62xeg@public.gmane.org>

Given appropriate devicetree bindings, this driver registers a
pm_power_off function to set a GPIO line high/low to power down
your board.

This feature will be useful for the Tegra TrimSlice board too.

+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".

Unfortunately, not all GPIO bindings support active high/low flags in
the GPIO specifier. As such, the flags there are basically useless.
Other bindings (e.g. IIRC the fixed-regulator binding) have added a
separate active-high property to indicate the GPIO polarity. This
binding should probably follow suite.