[alsa-devel] [PATCH RFC v5 4/8] drm/i2c: tda998x: Add support of a DT graph of ports

[Jean-Francois Moine]

On Thu, 18 Feb 2016 08:35:30 -0600
Rob Herring <robh at kernel.org> wrote:

> On Wed, Feb 17, 2016 at 04:49:05PM +0200, Jyri Sarha wrote:
> > From: Jean-Francois Moine <moinejf at free.fr>
> > 
> > Two kinds of ports may be declared in a DT graph of ports: video and audio.
> > This patch accepts the port value from a video port as an alternative
> > to the video-ports property.
> > It also accepts audio ports in the case the transmitter is not used as
> > a slave encoder.
> > The new file include/sound/tda998x.h prepares to the definition of
> > a tda998x CODEC.
> > 
> > Signed-off-by: Jean-Francois Moine <moinejf at free.fr>
> > Signed-off-by: Jyri Sarha <jsarha at ti.com>
> > ---
> >  .../devicetree/bindings/display/bridge/tda998x.txt | 51 ++++++++++++
> >  drivers/gpu/drm/i2c/tda998x_drv.c                  | 90 +++++++++++++++++++---
> >  include/sound/tda998x.h                            |  8 ++
> >  3 files changed, 140 insertions(+), 9 deletions(-)
> >  create mode 100644 include/sound/tda998x.h
> > 
> > diff --git a/Documentation/devicetree/bindings/display/bridge/tda998x.txt b/Documentation/devicetree/bindings/display/bridge/tda998x.txt
> > index e9e4bce..35f6a80 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/tda998x.txt
> > +++ b/Documentation/devicetree/bindings/display/bridge/tda998x.txt
> > @@ -16,6 +16,35 @@ Optional properties:
> >  
> >    - video-ports: 24 bits value which defines how the video controller
> >  	output is wired to the TDA998x input - default: <0x230145>
> > +	This property is not used when ports are defined.
> > +
> > +Optional nodes:
> > +
> > +  - port: up to three ports.
> > +	The ports are defined according to [1].
> > +
> > +    Video port.
> > +	There may be only one video port.
> > +	This one must contain the following property:
> > +
> > +	- port-type: must be "rgb"
> 
> This should be implied from the port unit address. In other words, 
> port at 0 is defined to be the rgb port. Now, if this is one of several 
> modes for the video port, then that is a different story.
> 
> > +	and may contain the optional property:
> > +
> > +	- reg: 24 bits value which defines how the video controller
> > +		output is wired to the TDA998x input (video pins)
> > +		When absent, the default value is <0x230145>.
> 
> This is not really how reg is intended to be used. Can you explain how 
> this value is determined?
> 
> > +    Audio ports.
> > +	There may be one or two audio ports.
> > +	These ones must contain the following properties:
> > +
> > +	- port-type: must be "i2s" or "spdif"
> > +
> > +	- reg: 8 bits value which defines how the audio controller
> > +		output is wired to the TDA998x input (audio pins)
> 
> Same here.

Hi Rob,

These audio/video port definitions were discussed in the thread
http://mailman.alsa-project.org/pipermail/alsa-devel/2015-August/095836.html
but, you are right, and as you already said in the thread 
https://lists.freedesktop.org/archives/dri-devel/2015-September/090544.html
'reg' should not be used here.

I would have changed to 'port-value', but as I will not update the
kernel of my Dove Cubox anymore, I will not propose a new version of
this patch (and, sorry Jyri, I will not test your patch series).

-- 
Ken ar c'hentañ	|	      ** Breizh ha Linux atav! **
Jef		|		http://moinejf.free.fr/