diff options
Diffstat (limited to 'Documentation/devicetree/bindings/media/cec-gpio.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/media/cec-gpio.txt | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt index 12fcd55ed153..47e8d73d32a3 100644 --- a/Documentation/devicetree/bindings/media/cec-gpio.txt +++ b/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: @@ -19,18 +19,24 @@ 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> cec-gpio { - compatible = "cec-gpio"; - cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; - hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>; + 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>; }; |