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-rw-r--r--dts/Bindings/media/cec-gpio.txt22
1 files changed, 14 insertions, 8 deletions
diff --git a/dts/Bindings/media/cec-gpio.txt b/dts/Bindings/media/cec-gpio.txt
index 12fcd55..47e8d73 100644
--- a/dts/Bindings/media/cec-gpio.txt
+++ b/dts/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>;
};