From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Subject: [PATCH v2 2/4] dt-bindings: gpio: add raspberry pi GPIO expander binding Date: Thu, 11 Jan 2018 21:44:25 +0200 Message-ID: References: Return-path: In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org To: Dave Stevenson , Eric Anholt , Stefan Wahren , Linus Walleij Cc: linux-gpio@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Michael Zoran , Baruch Siach List-Id: devicetree@vger.kernel.org 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 --- v2: * Rename compatible string to raspberrypi,firmware-gpio --- .../bindings/gpio/raspberrypi,firmware-gpio.txt | 24 ++++++++++++++++++++++ 1 file changed, 24 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..8faf269cf541 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt @@ -0,0 +1,24 @@ +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. + +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 +- firmware : Reference to the RPi firmware device node + +Example: + +expgpio: expgpio { + compatible = "raspberrypi,firmware-gpio"; + gpio-controller; + #gpio-cells = <2>; + firmware = <&firmware>; +}; -- 2.15.1