From: Hans Verkuil <>

This driver adds support for CEC implementations that use a pull-up
GPIO pin. While SoCs exist that do this, the primary use-case is to
turn a single-board computer into a cheap CEC debugger.

Together with 'cec-ctl --monitor-pin' you can do low-level CEC bus
monitoring and do protocol analysis. And error injection is also
planned for the future.

Here is an example using the Raspberry Pi 3:

A patch for the Raspberry Pi 2B/3 is added below for reference.
It uses pin 7 aka BCM4 aka GPCLK0 on the GPIO pin header.

While this example is for the Rpi, this driver will work for any
SoC with a pull-up GPIO pin.

I have one question: is there a generic way to check/force the gpio
to pull-up mode? I have not found that, but I am no gpio-expert.



Changes since v1:

- Updated the bindings doc to not refer to the driver, instead
  refer to the hardware.

Hans Verkuil (3):
  dt-bindings: document the CEC GPIO bindings
  cec-gpio: add HDMI CEC GPIO driver
  MAINTAINERS: add cec-gpio entry

 .../devicetree/bindings/media/cec-gpio.txt         |  16 ++
 MAINTAINERS                                        |   9 +
 drivers/media/platform/Kconfig                     |  10 ++
 drivers/media/platform/Makefile                    |   2 +
 drivers/media/platform/cec-gpio/Makefile           |   1 +
 drivers/media/platform/cec-gpio/cec-gpio.c         | 190 +++++++++++++++++++++
 6 files changed, 228 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
 create mode 100644 drivers/media/platform/cec-gpio/Makefile
 create mode 100644 drivers/media/platform/cec-gpio/cec-gpio.c


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