Document the GPIO device tree binding for Broadcom Cygnus SoC
Signed-off-by: Ray Jui <rjui@xxxxxxxxxxxx>
Reviewed-by: Scott Branden <sbranden@xxxxxxxxxxxx>
---
.../devicetree/bindings/gpio/brcm,cygnus-gpio.txt | 85 ++++++++++++++++++++
1 file changed, 85 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/brcm,cygnus-gpio.txt
diff --git a/Documentation/devicetree/bindings/gpio/brcm,cygnus-gpio.txt b/Documentation/devicetree/bindings/gpio/brcm,cygnus-gpio.txt
new file mode 100644
index 0000000..24a1513
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/brcm,cygnus-gpio.txt
@@ -0,0 +1,85 @@
+Broadcom Cygnus GPIO Controller
+
+Required properties:
+
+- compatible:
+ Currently supported Cygnus GPIO controllers include:
+ "brcm,cygnus-ccm-gpio": ChipcommonG GPIO controller
+ "brcm,cygnus-asiu-gpio": ASIU GPIO controller
+ "brcm,cygnus-crmu-gpio": CRMU GPIO controller
+
+- reg:
+ Define the base and range of the I/O address space that contain the Cygnus
+GPIO controller registers
+
+- ngpios:
+ Total number of GPIOs the controller provides
+
+- #gpio-cells:
+ Must be two. The first cell is the GPIO pin number (within the
+controller's domain) and the second cell is used for the following:
+ bit[0]: polarity (0 for normal and 1 for inverted)
+ bit[18:16]: internal pull up/down: 0 - pull up/down disabled
+ 1 - pull up enabled
+ 2 - pull down enabled
+ bit[22:20]: drive strength: 0 - 2 mA
+ 1 - 4 mA
+ 2 - 6 mA
+ 3 - 8 mA
+ 4 - 10 mA
+ 5 - 12 mA
+ 6 - 14 mA
+ 7 - 16 mA
+
+- gpio-controller:
+ Specifies that the node is a GPIO controller
+
+Optional properties:
+
+- interrupt-controller:
+ Specifies that the node is an interrupt controller. Not all Cygnus GPIO
+interfaces support interrupt, e.g., the CRMU GPIO controller does not have its
+interrupt routed to the main processor's GIC
+
+- interrupts:
+ The interrupt outputs from the GPIO controller.
+
+- no-interrupt:
+ Specifies that the GPIO interface does not support interrupt
+
+Example:
+ gpio_asiu: gpio@180a5000 {
+ compatible = "brcm,cygnus-asiu-gpio";
+ reg = <0x180a5000 0x668>;
+ ngpios = <122>;
+ #gpio-cells = <2>;
+ gpio-controller;
+ interrupt-controller;
+ interrupts = <GIC_SPI 174 IRQ_TYPE_LEVEL_HIGH>;
+ };
+
+ gpio_crmu: gpio@03024800 {
+ compatible = "brcm,cygnus-crmu-gpio";
+ reg = <0x03024800 0x50>;
+ ngpios = <6>;
+ #gpio-cells = <2>;
+ gpio-controller;
+ no-interrupt;
+ };
+
+ /*
+ * Touchscreen that uses the ASIU GPIO 100, with internal pull-up
+ * enabled
+ */
+ tsc {
+ ...
+ ...
+ gpio-event = <&gpio_asiu 100 0x10000>;
+ };
+
+ /* Bluetooth that uses the CRMU GPIO 2, with polarity inverted */
+ bluetooth {
+ ...
+ ...
+ bcm,rfkill-bank-sel = <&gpio_crmu 2 1>
+ }
--
1.7.9.5
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