[PATCH v5 2/5] dt-bindings: gpio: add raspberry pi GPIO expander binding
From: Baruch Siach <baruch@tkos.co.il>
Date: 2018-02-20 12:19:32
Also in:
linux-arm-kernel, linux-gpio
Subsystem:
gpio subsystem, open firmware and flattened device tree bindings, the rest · Maintainers:
Linus Walleij, Bartosz Golaszewski, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
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@tkos.co.il> --- 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