* Patch "media: dt-bindings/media/cec-gpio.txt: mention the CEC/HPD max voltages" has been added to the 4.15-stable tree
@ 2018-02-15 8:34 gregkh
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From: gregkh @ 2018-02-15 8:34 UTC (permalink / raw)
To: hverkuil, gregkh, hans.verkuil, mchehab, robh; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
media: dt-bindings/media/cec-gpio.txt: mention the CEC/HPD max voltages
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-dt-bindings-media-cec-gpio.txt-mention-the-cec-hpd-max-voltages.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From dac15ed62dc9d7898d3695a3c393d6f712d66185 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil@xs4all.nl>
Date: Sat, 16 Dec 2017 05:44:13 -0500
Subject: media: dt-bindings/media/cec-gpio.txt: mention the CEC/HPD max voltages
From: Hans Verkuil <hverkuil@xs4all.nl>
commit dac15ed62dc9d7898d3695a3c393d6f712d66185 upstream.
Mention the maximum voltages of the CEC and HPD lines. Since in the example
these lines are connected to a Raspberry Pi and the Rpi GPIO lines are 3.3V
it is a good idea to warn against directly connecting the HPD to the Raspberry
Pi's GPIO line.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/devicetree/bindings/media/cec-gpio.txt | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/Documentation/devicetree/bindings/media/cec-gpio.txt
+++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
@@ -4,6 +4,10 @@ The HDMI CEC GPIO module supports CEC im
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
+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
@@ -21,7 +25,7 @@ the following property is optional:
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:
+connected to pin 11 aka BCM17 (some level shifter is needed for this!):
#include <dt-bindings/gpio/gpio.h>
Patches currently in stable-queue which might be from hverkuil@xs4all.nl are
queue-4.15/media-dt-bindings-media-cec-gpio.txt-mention-the-cec-hpd-max-voltages.patch
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2018-02-15 8:34 Patch "media: dt-bindings/media/cec-gpio.txt: mention the CEC/HPD max voltages" has been added to the 4.15-stable tree gregkh
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