The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware over
I2C. The firmware mailbox interface allows the ARM core to control the
GPIO lines.
Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx>
---
v5:
* Remove the 'firmware' property
* Note that the gpio node is a child of the firmware node
v4:
* Move the example gpio node under the firmware node
* Rename gpio node name to plain 'gpio'
v3:
* Rename node name.
v2:
* Rename compatible string to raspberrypi,firmware-gpio
---
.../bindings/gpio/raspberrypi,firmware-gpio.txt | 30 ++++++++++++++++++++++
1 file changed, 30 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
diff --git a/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
new file mode 100644
index 000000000000..ce97265e23ba
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
@@ -0,0 +1,30 @@
+Raspberry Pi GPIO expander
+
+The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware. The
+firmware exposes a mailbox interface that allows the ARM core to control the
+GPIO lines on the expander.
+
+The Raspberry Pi GPIO expander node must be a child node of the Raspberry Pi
+firmware node.
+
+Required properties:
+
+- compatible : Should be "raspberrypi,firmware-gpio"
+- gpio-controller : Marks the device node as a gpio controller
+- #gpio-cells : Should be two. The first cell is the pin number, and
+ the second cell is used to specify the gpio polarity:
+ 0 = active high
+ 1 = active low
+
+Example:
+
+firmware: firmware-rpi {
+ compatible = "raspberrypi,bcm2835-firmware";
+ mboxes = <&mailbox>;
+
+ expgpio: gpio {
+ compatible = "raspberrypi,firmware-gpio";
+ gpio-controller;
+ #gpio-cells = <2>;
+ };
+};
--
2.16.1
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
