From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- .../devicetree/bindings/media/cec-gpio.txt | 42 ++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt (limited to '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 000000000..47e8d73d3 --- /dev/null +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt @@ -0,0 +1,42 @@ +* 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. + +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: + - compatible: value must be "cec-gpio". + - cec-gpios: gpio that the CEC line is connected to. The line should be + tagged as open drain. + +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 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, 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 + +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>; +}; -- cgit v1.2.3