Re: [PATCH 1/5] cec-gpio.txt: add v5-gpios for testing the 5V line

[Rob Herring <robh@kernel.org>]

On Tue, Jul 17, 2018 at 03:29:05PM +0200, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> In order to debug the HDMI 5V line we need to add a new v5-gpios
> property.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  .../devicetree/bindings/media/cec-gpio.txt      | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
> index 12fcd55ed153..1d53ce89da74 100644
> --- a/Documentation/devicetree/bindings/media/cec-gpio.txt
> +++ b/Documentation/devicetree/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:
> @@ -22,15 +22,18 @@ 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.
> +  - v5-gpios: gpio that the 5V line is connected to.

This is a bit strange without the context of debugging. So can you 
mention that here.

With that,

Reviewed-by: Rob Herring <robh@kernel.org>

>  
>  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>;
>  };
> -- 
> 2.18.0
>