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authorHans Verkuil <hans.verkuil@cisco.com>2017-08-02 03:22:33 -0400
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2017-09-23 07:50:18 -0400
commit67f2a06f14a9419bc2da0a8e6b440c6813dccdb0 (patch)
tree597a75873d990db2c9bb844a09fe9505957d571f /Documentation
parent00f7adff0c3a1d793ffa213c28d82c47dfd8ab04 (diff)
media: dt-bindings: document the CEC GPIO bindings
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@cisco.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
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+* 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. 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:
+
+ - 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:
+
+#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>;
+};