Hi Hans,

On 19-08-16 13:11, Hans Verkuil wrote:
> On 8/15/19 1:57 PM, Marco Felsch wrote:
> > Some connectors no matter if in- or output supports only a limited
> > range of tv norms. It doesn't matter if the hardware behind that
> > connector supports more than the listed formats since the users are
> > restriced by a label e.g. to plug only a camera into this connector
> > which uses the PAL format.
> > 
> > This patch adds the capability to describe such limitation within the
> > firmware. There are no format restrictions if the property isn't
> > present, so it's completely backward compatible.
> > 
> > Signed-off-by: Marco Felsch <m.fel...@pengutronix.de>
> > Reviewed-by: Rob Herring <r...@kernel.org>
> > ---
> > [1] https://patchwork.kernel.org/cover/10794703/
> > 
> > v7:
> > I kept Robs r b tag because I only changed the example and extended
> > TVNORM_* macros.
> > 
> > - fix some style issues
> > - add TVNORM_NTSC, TVNORM_525_60 and TVNORM_625_50
> > 
> > v6:
> > - tvnorms.h: use tabs instead of spaces
> > - tvnorms.h: add TVNORM_PAL and TVNORM_SECAM
> > - tvnorms.h: drop rarely used TVNORM_ATSC_* norms
> > 
> > v2-v4:
> > - nothing since the patch was squashed from series [1] into this
> >   series.
> > ---
> >  .../display/connector/analog-tv-connector.txt |  4 ++
> >  include/dt-bindings/media/tvnorms.h           | 72 +++++++++++++++++++
> >  2 files changed, 76 insertions(+)
> >  create mode 100644 include/dt-bindings/media/tvnorms.h
> > 
> > diff --git 
> > a/Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt
> >  
> > b/Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt
> > index 0c0970c210ab..434e8aa0398b 100644
> > --- 
> > a/Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt
> > +++ 
> > b/Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt
> > @@ -6,6 +6,9 @@ Required properties:
> >  
> >  Optional properties:
> >  - label: a symbolic name for the connector
> > +- tvnorms: limit the supported tv norms on a connector to the given ones 
> > else
> 
> tv -> TV
> 
> > +           all tv norms are allowed. Possible video standards are defined 
> > in
> 
> tv -> TV

Changed both thanks.

> And a more high-level question: I think tvnorm is a very vague name. It's a 
> term
> used in media, but what does 'norm' mean anyway? 'tv_standards' or 
> 'video_standards'
> would be a lot more descriptive.

I'm with you *_standards would be more descriptive. Now the question is:
is it a video or a tv standard? Wikipedia says that SECAM, PAL, NTSC is
a television standard. So I prefer the 'tv_standards' or better the
'tv-standards' approach.

> 'tvnorm' is, I think, a term used only internally in the media subsystem for 
> no
> clear reason. In the V4L2 spec it talks about 'video standard'.
> 
> Sorry for being so late with raising this issue.
> 
> > +           include/dt-bindings/media/tvnorms.h.
> >  
> >  Required nodes:
> >  - Video port for TV input
> > @@ -16,6 +19,7 @@ Example
> >  tv: connector {
> >     compatible = "composite-video-connector";
> >     label = "tv";
> > +   tvnorms = <(TVNORM_PAL | TVNORM_NTSC)>;
> >  
> >     port {
> >             tv_connector_in: endpoint {
> > diff --git a/include/dt-bindings/media/tvnorms.h 
> > b/include/dt-bindings/media/tvnorms.h
> > new file mode 100644
> > index 000000000000..e1275673c4d6
> > --- /dev/null
> > +++ b/include/dt-bindings/media/tvnorms.h
> > @@ -0,0 +1,72 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only or X11 */
> > +/*
> > + * Copyright 2019 Pengutronix, Marco Felsch <ker...@pengutronix.de>
> > + */
> > +
> > +#ifndef _DT_BINDINGS_MEDIA_TVNORMS_H
> > +#define _DT_BINDINGS_MEDIA_TVNORMS_H
> > +
> > +/* One bit for each standard */
> 
> I would add a comment here and in videodev2.h where you mention that
> the two headers should remain in sync.

Yes, good point.

> > +#define TVNORM_PAL_B               0x00000001
> > +#define TVNORM_PAL_B1              0x00000002
> > +#define TVNORM_PAL_G               0x00000004
> > +#define TVNORM_PAL_H               0x00000008
> > +#define TVNORM_PAL_I               0x00000010
> > +#define TVNORM_PAL_D               0x00000020
> > +#define TVNORM_PAL_D1              0x00000040
> > +#define TVNORM_PAL_K               0x00000080
> > +
> > +#define TVNORM_PAL         (TVNORM_PAL_B           | \
> > +                            TVNORM_PAL_B1          | \
> > +                            TVNORM_PAL_G           | \
> > +                            TVNORM_PAL_H           | \
> > +                            TVNORM_PAL_I           | \
> > +                            TVNORM_PAL_D           | \
> > +                            TVNORM_PAL_D1          | \
> > +                            TVNORM_PAL_K)
> > +
> > +#define TVNORM_PAL_M               0x00000100
> > +#define TVNORM_PAL_N               0x00000200
> > +#define TVNORM_PAL_Nc              0x00000400
> > +#define TVNORM_PAL_60              0x00000800
> > +
> > +#define TVNORM_NTSC_M              0x00001000      /* BTSC */
> > +#define TVNORM_NTSC_M_JP   0x00002000      /* EIA-J */
> > +#define TVNORM_NTSC_443            0x00004000
> > +#define TVNORM_NTSC_M_KR   0x00008000      /* FM A2 */
> > +
> > +#define TVNORM_NTSC                (TVNORM_NTSC_M          |\
> > +                            TVNORM_NTSC_M_JP       |\
> 
> Add space before \
> 
> > +                            TVNORM_NTSC_M_KR)
> > +
> > +#define TVNORM_SECAM_B             0x00010000
> > +#define TVNORM_SECAM_D             0x00020000
> > +#define TVNORM_SECAM_G             0x00040000
> > +#define TVNORM_SECAM_H             0x00080000
> > +#define TVNORM_SECAM_K             0x00100000
> > +#define TVNORM_SECAM_K1            0x00200000
> > +#define TVNORM_SECAM_L             0x00400000
> > +#define TVNORM_SECAM_LC            0x00800000
> > +
> > +#define TVNORM_SECAM               (TVNORM_SECAM_B         | \
> > +                            TVNORM_SECAM_D         | \
> > +                            TVNORM_SECAM_G         | \
> > +                            TVNORM_SECAM_H         | \
> > +                            TVNORM_SECAM_K         | \
> > +                            TVNORM_SECAM_K1        | \
> > +                            TVNORM_SECAM_L         | \
> > +                            TVNORM_SECAM_LC)
> > +
> > +/* Standards for Countries with 60Hz Line frequency */
> > +#define TVNORM_525_60              (TVNORM_PAL_M           | \
> > +                            TVNORM_PAL_60          | \
> > +                            TVNORM_NTSC            | \
> > +                            TVNORM_NTSC_443)
> > +
> > +/* Standards for Countries with 50Hz Line frequency */
> > +#define TVNORM_625_50              (TVNORM_PAL             |\
> > +                            TVNORM_PAL_N           |\
> > +                            TVNORM_PAL_Nc          |\
> 
> Add space before \

Both space errors fixed.

> > +                            TVNORM_SECAM)
> > +
> > +#endif /* _DT_BINDINGS_MEDIA_TVNORMS_H */
> > 
> 
> I was also wondering if this header shouldn't be in 
> include/dt-bindings/display/
> since the bindings are also described in 'display'.

That's a good one and I really don't know which is the 'right' place for
it. Since the standard has nothing to do with a display I would keep it
within media. But the radeon [1] gpu uses the stds too. So I really
don't know which place is better.

[1] drivers/gpu/drm/radeon/radeon_mode.h. 

Regards,
  Marco

> Regards,
> 
>       Hans
> 

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