dt: Move device tree documentation out of powerpc directory

The device tree is used by more than just PowerPC.  Make the documentation
directory available to all.

v2: reorganized files while moving to create arch and driver specific
    directories.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt
new file mode 100644
index 000000000000..b0019eb5330e
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt
@@ -0,0 +1,60 @@
+GPIO controllers on MPC8xxx SoCs
+
+This is for the non-QE/CPM/GUTs GPIO controllers as found on
+8349, 8572, 8610 and compatible.
+
+Every GPIO controller node must have #gpio-cells property defined,
+this information will be used to translate gpio-specifiers.
+
+Required properties:
+- compatible : "fsl,<CHIP>-gpio" followed by "fsl,mpc8349-gpio" for
+  83xx, "fsl,mpc8572-gpio" for 85xx and "fsl,mpc8610-gpio" for 86xx.
+- #gpio-cells : Should be two. The first cell is the pin number and the
+  second cell is used to specify optional parameters (currently unused).
+ - interrupts : Interrupt mapping for GPIO IRQ.
+ - interrupt-parent : Phandle for the interrupt controller that
+   services interrupts for this device.
+- gpio-controller : Marks the port as GPIO controller.
+
+Example of gpio-controller nodes for a MPC8347 SoC:
+
+        gpio1: gpio-controller@c00 {
+                #gpio-cells = <2>;
+                compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio";
+                reg = <0xc00 0x100>;
+                interrupts = <74 0x8>;
+                interrupt-parent = <&ipic>;
+                gpio-controller;
+        };
+
+        gpio2: gpio-controller@d00 {
+                #gpio-cells = <2>;
+                compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio";
+                reg = <0xd00 0x100>;
+                interrupts = <75 0x8>;
+                interrupt-parent = <&ipic>;
+                gpio-controller;
+        };
+
+See booting-without-of.txt for details of how to specify GPIO
+information for devices.
+
+To use GPIO pins as interrupt sources for peripherals, specify the
+GPIO controller as the interrupt parent and define GPIO number +
+trigger mode using the interrupts property, which is defined like
+this:
+
+interrupts = <number trigger>, where:
+ - number: GPIO pin (0..31)
+ - trigger: trigger mode:
+        2 = trigger on falling edge
+        3 = trigger on both edges
+
+Example of device using this is:
+
+        funkyfpga@0 {
+                compatible = "funky-fpga";
+                ...
+                interrupts = <4 3>;
+                interrupt-parent = <&gpio1>;
+        };