dm: exynos: Bring in GPIO device tree binding
authorSimon Glass <sjg@chromium.org>
Tue, 6 Jan 2015 03:05:24 +0000 (20:05 -0700)
committerSimon Glass <sjg@chromium.org>
Fri, 30 Jan 2015 00:09:50 +0000 (17:09 -0700)
At present the exynos GPIO driver does not fully support the existing device
tree binding, but add the binding file to cover the existing partial support.

Signed-off-by: Simon Glass <sjg@chromium.org>
doc/device-tree-bindings/gpio/gpio-samsung.txt [new file with mode: 0644]

diff --git a/doc/device-tree-bindings/gpio/gpio-samsung.txt b/doc/device-tree-bindings/gpio/gpio-samsung.txt
new file mode 100644 (file)
index 0000000..5375625
--- /dev/null
@@ -0,0 +1,41 @@
+Samsung Exynos4 GPIO Controller
+
+Required properties:
+- compatible: Compatible property value should be "samsung,exynos4-gpio>".
+
+- reg: Physical base address of the controller and length of memory mapped
+  region.
+
+- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes
+  should be the following with values derived from the SoC user manual.
+     <[phandle of the gpio controller node]
+      [pin number within the gpio controller]
+      [mux function]
+      [flags and pull up/down]
+      [drive strength]>
+
+  Values for gpio specifier:
+  - Pin number: is a value between 0 to 7.
+  - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled.
+                            1 - Pull Down Enabled.
+                            3 - Pull Up Enabled.
+          Bit 16 (0x00010000) - Input is active low.
+  - Drive Strength: 0 - 1x,
+                    1 - 3x,
+                    2 - 2x,
+                    3 - 4x
+
+- gpio-controller: Specifies that the node is a gpio controller.
+- #address-cells: should be 1.
+- #size-cells: should be 1.
+
+Example:
+
+       gpa0: gpio-controller@11400000 {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               compatible = "samsung,exynos4-gpio";
+               reg = <0x11400000 0x20>;
+               #gpio-cells = <4>;
+               gpio-controller;
+       };