Re: [PATCH 20/22] [media] tvp5150: Add input port connectors DT bindings

Marco Felsch
2018-08-03T07:29:53Z

Hi Rob,

first of all, thanks for the review. After some discussion with the
media guys I have a question about the dt-bindings.

On 18-07-03 17:23, Rob Herring wrote:
> On Thu, Jun 28, 2018 at 06:20:52PM +0200, Marco Felsch wrote:
> > The TVP5150/1 decoders support different video input sources to their
> > AIP1A/B pins.
> >
> > Possible configurations are as follows:
> > - Analog Composite signal connected to AIP1A.
> > - Analog Composite signal connected to AIP1B.
> > - Analog S-Video Y (luminance) and C (chrominance)
> > signals connected to AIP1A and AIP1B respectively.
> >
> > This patch extends the device tree bindings documentation to describe
> > how the input connectors for these devices should be defined in a DT.
> >
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > ---
> > .../devicetree/bindings/media/i2c/tvp5150.txt | 118 +++++++++++++++++-
> > 1 file changed, 113 insertions(+), 5 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/media/i2c/tvp5150.txt b/Documentation/devicetree/bindings/media/i2c/tvp5150.txt
> > index 8c0fc1a26bf0..feed8c911c5e 100644
> > --- a/Documentation/devicetree/bindings/media/i2c/tvp5150.txt
> > +++ b/Documentation/devicetree/bindings/media/i2c/tvp5150.txt
> > @@ -12,11 +12,23 @@ Optional Properties:
> > - pdn-gpios: phandle for the GPIO connected to the PDN pin, if any.
> > - reset-gpios: phandle for the GPIO connected to the RESETB pin, if any.
> >
> > -The device node must contain one 'port' child node for its digital output
> > -video port, in accordance with the video interface bindings defined in
> > -Documentation/devicetree/bindings/media/video-interfaces.txt.
> > +The device node must contain one 'port' child node per device input and output
> > +port, in accordance with the video interface bindings defined in
> > +Documentation/devicetree/bindings/media/video-interfaces.txt. The port nodes
> > +are numbered as follows
> >
> > -Required Endpoint Properties for parallel synchronization:
> > + Name Type Port
> > + --------------------------------------
> > + AIP1A sink 0
> > + AIP1B sink 1
> > + S-VIDEO sink 2
> > + Y-OUT src 3

Do you think it's correct to have a seperate port for each binding?
Since the S-Video port is a combination of AIP1A and AIP1B. After a
discussion with Mauro [1] the TVP5150 should have only 3 pads. Since the
pads are directly mappped to the dt-ports this will correspond to three
ports (2 in, 1 out). Now the svideo connector will be mapped to a second
endpoint in each port:

port@0
endpoint@0 -----------> Comp0-Con
endpoint@1 -----+-----> Svideo-Con
port@1 |
endpoint@0 -----|-----> Comp1-Con
endpoint@1 -----+
port@2
endpoint

I don't like that solution that much, since the mapping is now signal
based. We also don't map each line of a parallel port.

A quick grep shows that currently each device using a svideo connector
seperates them in a own port as I did. IMHO this is a uncomplicate
solution, but don't abstract the HW correctly. What is your opinion
about that? Is it correct to have seperate (virtual) port or should I
map the svideo connector as shown above?

[1] https://www.spinics.net/lists/devicetree/msg242825.html

Regards,
Marco

> > +
> > +The device node must contain at least the Y-OUT port. Each input port must be
> > +linked to an endpoint defined in
> > +Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt.
> > +
> > +Required Endpoint Properties for parallel synchronization on output port:
> >
> > - hsync-active: active state of the HSYNC signal. Must be <1> (HIGH).
> > - vsync-active: active state of the VSYNC signal. Must be <1> (HIGH).
> > @@ -26,7 +38,9 @@ Required Endpoint Properties for parallel synchronization:
> > If none of hsync-active, vsync-active and field-even-active is specified,
> > the endpoint is assumed to use embedded BT.656 synchronization.
> >
> > -Example:
> > +Examples:
> > +
> > +Only Output:
> >
> > &i2c2 {
> > ...
> > @@ -37,6 +51,100 @@ Example:
> > reset-gpios = <&gpio6 7 GPIO_ACTIVE_LOW>;
> >
> > port {
> > + reg = <3>;
> > + tvp5150_1: endpoint {
> > + remote-endpoint = <&ccdc_ep>;
> > + };
> > + };
> > + };
> > +};
> > +
> > +One Input:
> > +
> > +connector@0 {
>
> Drop the unit-address as there is no reg property.
>
> > + compatible = "composite-video-connector";
> > + label = "Composite0";
> > +
> > + port {
> > + comp0_out: endpoint {
> > + remote-endpoint = <&tvp5150_comp0_in>;
> > + };
> > + };
> > +};
> > +
> > +&i2c2 {
> > + ...
> > + tvp5150@5c {
> > + compatible = "ti,tvp5150";
> > + reg = <0x5c>;
> > + pdn-gpios = <&gpio4 30 GPIO_ACTIVE_LOW>;
> > + reset-gpios = <&gpio6 7 GPIO_ACTIVE_LOW>;
> > +
> > + port@0 {
> > + reg = <0>;
> > + tvp5150_comp0_in: endpoint {
> > + remote-endpoint = <&comp0_out>;
> > + };
> > + };
> > +
> > + port@3 {
> > + reg = <3>;
> > + tvp5150_1: endpoint {
> > + remote-endpoint = <&ccdc_ep>;
> > + };
> > + };
> > + };
> > +};
> > +
> > +
> > +Two Inputs, different connector 12 on input AIP1A:
> > +
> > +connector@1 {
>
> ditto
>
> > + compatible = "svideo-connector";
> > + label = "S-Video";
> > +
> > + port {
> > + svideo_out: endpoint {
> > + remote-endpoint = <&tvp5150_svideo_in>;
> > + };
> > + };
> > +};
> > +
> > +connector@12 {
>
> ditto
>
> > + compatible = "composite-video-connector";
> > + label = "Composite12";
> > +
> > + port {
> > + comp12_out: endpoint {
> > + remote-endpoint = <&tvp5150_comp12_in>;
> > + };
> > + };
> > +};
> > +
> > +&i2c2 {
> > + ...
> > + tvp5150@5c {
> > + compatible = "ti,tvp5150";
> > + reg = <0x5c>;
> > + pdn-gpios = <&gpio4 30 GPIO_ACTIVE_LOW>;
> > + reset-gpios = <&gpio6 7 GPIO_ACTIVE_LOW>;
> > +
> > + port@0 {
> > + reg = <0>;
> > + tvp5150_comp12_in: endpoint {
> > + remote-endpoint = <&comp12_out>;
> > + };
> > + };
> > +
> > + port@2 {
> > + reg = <2>;
> > + tvp5150_svideo_in: endpoint {
> > + remote-endpoint = <&svideo_out>;
> > + };
> > + };
> > +
> > + port@3 {
> > + reg = <3>;
> > tvp5150_1: endpoint {
> > remote-endpoint = <&ccdc_ep>;
> > };
> > --
> > 2.17.1
> >
>

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