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authorSimon Glass <sjg@chromium.org>2015-01-05 20:05:24 -0700
committerSimon Glass <sjg@chromium.org>2015-01-29 17:09:50 -0700
commit35ea1bfde30a541188ffd24cdf9b3ba79b0e4684 (patch)
tree76dbfe666a81dd48159cfbe10c19f4d18cb4f44f /doc/device-tree-bindings
parent9f4cd0200cae9821f9ae7994b86ec7a2023bbcd0 (diff)
downloadblackbird-obmc-uboot-35ea1bfde30a541188ffd24cdf9b3ba79b0e4684.tar.gz
blackbird-obmc-uboot-35ea1bfde30a541188ffd24cdf9b3ba79b0e4684.zip
dm: exynos: Bring in GPIO device tree binding
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>
Diffstat (limited to 'doc/device-tree-bindings')
-rw-r--r--doc/device-tree-bindings/gpio/gpio-samsung.txt41
1 files changed, 41 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/gpio/gpio-samsung.txt b/doc/device-tree-bindings/gpio/gpio-samsung.txt
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+++ b/doc/device-tree-bindings/gpio/gpio-samsung.txt
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+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;
+ };
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