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authorThomas Abraham <thomas.abraham@linaro.org>2011-11-07 01:02:21 +0530
committerKukjin Kim <kgene.kim@samsung.com>2011-12-23 10:06:54 +0900
commit659d73ada5d6869dc18838c9125731a750389019 (patch)
tree1c46b7ee38c09391942f8ded59a16614e166499c /Documentation
parentf983575aa90ceeb2cc7923223882dcf1debf5aa2 (diff)
downloadop-kernel-dev-659d73ada5d6869dc18838c9125731a750389019.zip
op-kernel-dev-659d73ada5d6869dc18838c9125731a750389019.tar.gz
gpio/samsung: Add device tree support for EXYNOS4
As gpio chips get registered, a device tree node which represents the gpio chip is searched and attached to it. A translate function is also provided to convert the gpio specifier into actual platform settings for pin function selection, pull up/down and driver strength settings. Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org> Acked-by: Grant Likely <grant.likely@secretlab.ca> [kgene.kim@samsung.com: fixed build error] Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/gpio/gpio-samsung.txt40
1 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-samsung.txt b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
new file mode 100644
index 0000000..8f50fe5
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
@@ -0,0 +1,40 @@
+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]
+ [pull up/down]
+ [drive strength]>
+
+ Values for gpio specifier:
+ - Pin number: is a value between 0 to 7.
+ - Pull Up/Down: 0 - Pull Up/Down Disabled.
+ 1 - Pull Down Enabled.
+ 3 - Pull Up Enabled.
+ - 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;
+ };
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