media: cec-gpio.txt: add v5-gpios for testing the 5V line

In order to debug the HDMI 5V line we need to add a new v5-gpios
property.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/cec-gpio.txt

@@ -4,8 +4,8 @@ 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.
 
-Please note: the maximum voltage for the CEC line is 3.63V, for the HPD
-line it is 5.3V. So you may need some sort of level conversion circuitry
+Please note: the maximum voltage for the CEC line is 3.63V, for the HPD and
+5V lines it is 5.3V. So you may need some sort of level conversion circuitry
 when connecting them to a GPIO line.
 
 Required properties:
@@ -19,13 +19,18 @@ 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:
+the following property is optional and can be used for debugging HPD changes:
 
   - hpd-gpios: gpio that the HPD line is connected to.
 
+This property is optional and can be used for debugging changes on the 5V line:
+
+  - v5-gpios: gpio that the 5V 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 (some level shifter is needed for this!):
+pin 26 aka BCM7 aka CE1 on the GPIO pin header, the HPD line is
+connected to pin 11 aka BCM17 and the 5V line is connected to pin
+15 aka BCM22 (some level shifter is needed for the HPD and 5V lines!):
 
 #include <dt-bindings/gpio/gpio.h>
 
@@ -33,4 +38,5 @@ cec-gpio {
 	compatible = "cec-gpio";
 	cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
 	hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>;
+	v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;
 };