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authorDavid S. Miller <davem@davemloft.net>2011-02-20 04:17:35 +0100
committerDavid S. Miller <davem@davemloft.net>2011-02-20 04:17:35 +0100
commitda935c66bacb3ed9ada984b053297f87c2dff63a (patch)
tree46278da2b312c73f1375b830d7e5912bf23abd78 /Documentation/devicetree/bindings/gpio/gpio.txt
parentipv4: Implement __ip_dev_find using new interface address hash. (diff)
parentsctp: fix reporting of unknown parameters (diff)
downloadlinux-da935c66bacb3ed9ada984b053297f87c2dff63a.tar.xz
linux-da935c66bacb3ed9ada984b053297f87c2dff63a.zip
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts: Documentation/feature-removal-schedule.txt drivers/net/e1000e/netdev.c net/xfrm/xfrm_policy.c
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+Specifying GPIO information for devices
+============================================
+
+1) gpios property
+-----------------
+
+Nodes that makes use of GPIOs should define them using `gpios' property,
+format of which is: <&gpio-controller1-phandle gpio1-specifier
+ &gpio-controller2-phandle gpio2-specifier
+ 0 /* holes are permitted, means no GPIO 3 */
+ &gpio-controller4-phandle gpio4-specifier
+ ...>;
+
+Note that gpio-specifier length is controller dependent.
+
+gpio-specifier may encode: bank, pin position inside the bank,
+whether pin is open-drain and whether pin is logically inverted.
+
+Example of the node using GPIOs:
+
+ node {
+ gpios = <&qe_pio_e 18 0>;
+ };
+
+In this example gpio-specifier is "18 0" and encodes GPIO pin number,
+and empty GPIO flags as accepted by the "qe_pio_e" gpio-controller.
+
+2) gpio-controller nodes
+------------------------
+
+Every GPIO controller node must have #gpio-cells property defined,
+this information will be used to translate gpio-specifiers.
+
+Example of two SOC GPIO banks defined as gpio-controller nodes:
+
+ qe_pio_a: gpio-controller@1400 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank-a", "fsl,qe-pario-bank";
+ reg = <0x1400 0x18>;
+ gpio-controller;
+ };
+
+ qe_pio_e: gpio-controller@1460 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
+ reg = <0x1460 0x18>;
+ gpio-controller;
+ };
+
+