[PATCHv5 3/5] dt-bindings: document the CEC GPIO bindings

[Hans Verkuil]

From: Hans Verkuil <hans.verkuil at cisco.com>

Document the bindings for the cec-gpio module for hardware where the
CEC line and optionally the HPD line are connected to GPIO lines.

Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
---
 .../devicetree/bindings/media/cec-gpio.txt         | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt

diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
new file mode 100644
index 000000000000..1b7e13f36b08
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
@@ -0,0 +1,29 @@
+* HDMI CEC GPIO driver
+
+The HDMI CEC GPIO module supports CEC implementations where the CEC line
+is hooked up to a pull-up GPIO line and - optionally - the HPD line is
+hooked up to another GPIO line.
+
+Required properties:
+  - compatible: value must be "cec-gpio".
+  - cec-gpios: gpio that the CEC line is connected to.
+
+If the CEC line is associated with an HDMI receiver/transmitter, then the
+following property is also required:
+
+  - hdmi-phandle - phandle to the HDMI controller, see also cec.txt.
+
+If the CEC line is not associated with an HDMI receiver/transmitter, then
+the following property is optional:
+
+  - hpd-gpios: gpio that the HPD line is connected to.
+
+Example for the Raspberry Pi 3 where the CEC line is connected to
+pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
+connected to pin 11 aka BCM17:
+
+cec-gpio {
+       compatible = "cec-gpio";
+       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
+       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
+};
-- 
2.14.1