summaryrefslogtreecommitdiff
path: root/Documentation/devicetree
diff options
context:
space:
mode:
authorJohn Crispin <blogic@openwrt.org>2012-05-16 22:17:38 +0200
committerRalf Baechle <ralf@linux-mips.org>2012-05-21 14:31:53 +0100
commita36e9a1c5fa67cdc965fe011f1d04317adb35953 (patch)
tree8fc82e50f53c718c0e12785fb63f3fbeb270b383 /Documentation/devicetree
parent5238f7bc356670ba702057c7de7f07909133f788 (diff)
GPIO: MIPS: lantiq: convert gpio-mm-lantiq to OF and of_mm_gpio
Implements OF support and convert to of_mm_gpio. By attaching hardware latches to the External Bus Unit (EBU) on Lantiq SoC, it is possible to create output only gpios. This driver configures a special memory address, which when written to, outputs 16 bit to the latches. Signed-off-by: John Crispin <blogic@openwrt.org> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Acked-by: Grant Likely <grant.likely@secretlab.ca> Patchwork: https://patchwork.linux-mips.org/patch/3840/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt38
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt b/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt
new file mode 100644
index 000000000000..f93d51478d5a
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt
@@ -0,0 +1,38 @@
+Lantiq SoC External Bus memory mapped GPIO controller
+
+By attaching hardware latches to the EBU it is possible to create output
+only gpios. This driver configures a special memory address, which when
+written to outputs 16 bit to the latches.
+
+The node describing the memory mapped GPIOs needs to be a child of the node
+describing the "lantiq,localbus".
+
+Required properties:
+- compatible : Should be "lantiq,gpio-mm-lantiq"
+- reg : Address and length of the register set for the device
+- #gpio-cells : Should be two. The first cell is the pin number and
+ the second cell is used to specify optional parameters (currently
+ unused).
+- gpio-controller : Marks the device node as a gpio controller.
+
+Optional properties:
+- lantiq,shadow : The default value that we shall assume as already set on the
+ shift register cascade.
+
+Example:
+
+localbus@0 {
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges = <0 0 0x0 0x3ffffff /* addrsel0 */
+ 1 0 0x4000000 0x4000010>; /* addsel1 */
+ compatible = "lantiq,localbus", "simple-bus";
+
+ gpio_mm0: gpio@4000000 {
+ compatible = "lantiq,gpio-mm";
+ reg = <1 0x0 0x10>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ lantiq,shadow = <0x77f>
+ };
+}