media: cec-gpio: add HDMI CEC GPIO driver

Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.

While I have heard of SoCs that use the GPIO pin for CEC (apparently an
early RockChip SoC used that), the main use-case of this driver is to
function as a debugging tool.

By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example
it turns it into a CEC debugger and protocol analyzer.

With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.

But of course it can also be used with any hardware project where the
HDMI CEC line is hooked up to a pull-up gpio line.

In addition this has (optional) support for tracing HPD changes if the
HPD is connected to a GPIO.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 7e7cc49b8674..e4c89a16a3e7 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -553,6 +553,16 @@ config VIDEO_MESON_AO_CEC
 	  This is a driver for Amlogic Meson SoCs AO CEC interface. It uses the
 	  generic CEC framework interface.
 	  CEC bus is present in the HDMI connector and enables communication
+
+config CEC_GPIO
+	tristate "Generic GPIO-based CEC driver"
+	depends on PREEMPT
+	select CEC_CORE
+	select CEC_PIN
+	select GPIOLIB
+	---help---
+	  This is a generic GPIO-based CEC driver.
+	  The CEC bus is present in the HDMI connector and enables communication
 	  between compatible devices.
 
 config VIDEO_SAMSUNG_S5P_CEC