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From: Mauro Carvalho Chehab <mchehab@kernel.org>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Marco Felsch <m.felsch@pengutronix.de>,
	sakari.ailus@linux.intel.com, hans.verkuil@cisco.com,
	jacopo+renesas@jmondi.org, robh+dt@kernel.org,
	laurent.pinchart@ideasonboard.com, linux-media@vger.kernel.org,
	devicetree@vger.kernel.org, kernel@pengutronix.de,
	Rob Herring <robh@kernel.org>
Subject: Re: [PATCH v6 01/13] dt-bindings: connector: analog: add tv norms property
Date: Tue, 14 May 2019 15:11:19 -0300
Message-ID: <20190514151119.2099cd10@coco.lan> (raw)
In-Reply-To: <9989034f-4794-adba-d89c-8330bbf7b27f@xs4all.nl>

Em Mon, 6 May 2019 12:01:06 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> On 4/15/19 2:44 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.  
> 
> For S-Video and Composite connectors there are really just two formats
> to consider: 50 and 60 Hz. I.e. there is no difference between PAL
> and SECAM. Only for tuners/modulators does this matter.
> 
> So it is a good idea to add TVNORM_525_60, TVNORM_625_50 to tvnorms.h.
> 
> In the various bindings examples I would recommend that you use
> TVNORM_525_60 or TVNORM_625_50 rather than e.g. PAL_M since that's what
> you would use in practice for Composite/S-Video.

Hans, that could be true for component video, but for S-Video and
Composite, you need to tell the demod how the color sub-carrier is
encoded, and what's its frequency, or otherwise it won't work.

There are plenty of equipments in Brazil that have both NTSC/M and
PAL/M (and a few with PAL/N') output. All those formats are 60Hz.

Colors are only decoded by tvp5150 and other demods if it is set
to the right color format (PAL or NTSC) and to the right line 
frequency (60Hz) [1]. Also, some decoders are very sensitive to the
chroma sub-carrier frequency. That's the case of tvp5150.

[1] Or - when supported by the hardware - if the demod is set to
    automatic mode.

    Automatic mode usually doesn't work well with PAL/M and PAL/N'.

    The problem is related to the sub-carrier frequency: both 
    PAL/N' (used only on Paraguay) and NTSC/M have the same 
    frequency; PAL/M has a close but different frequency for the
    color sub-carrier.

    Most decoders use the frequency of the chroma sub-carrier in
    order to switch between NTSC/M nd PAL/M. So, auto-detection
    usually fails with PAL/N', as such detectors understand it
    as NTSC.

    Worse than that, it is not uncommon to have pseudo-PAL-M devices
    that were made for the US market, and received a conversion
    to PAL, with envolves adding a small board with a NTSC->PAL converter.
    As most TV sets used in this part of the world are designed to
    work both with PAL/M and PAL/N' (by using a broader notch filter),
    to make the hardware cheaper, lots of manufacturers just
    change the modulation on encoders, while keeping the NTSC XTAL.
    So, in practice, such devices, sold as "PAL/M" are actually PAL/N'.
    A significant amount of old VCRs and DVD devices found in Brazil
    are actually PAL/N'. The same applies to game consoles.

    Btw, the main reason for having analog video streams here nowadays
    is to copy old videos from VCRs and encode them digitally or to
    record games from game consoles.

> 
> Regards,
> 
> 	Hans
> 
> > 
> > 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.felsch@pengutronix.de>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > ---
> > [1] https://patchwork.kernel.org/cover/10794703/
> > 
> > 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           | 56 +++++++++++++++++++
> >  2 files changed, 60 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..346f8937a0b7 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
> > +           all tv norms are allowed. Possible video standards are defined in
> > +           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_M | TVNORM_NTSC_M)>;
> >  
> >  	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..058ab8414145
> > --- /dev/null
> > +++ b/include/dt-bindings/media/tvnorms.h
> > @@ -0,0 +1,56 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only or X11 */
> > +/*
> > + * Copyright 2019 Pengutronix, Marco Felsch <kernel@pengutronix.de>
> > + */
> > +
> > +#ifndef _DT_BINDINGS_MEDIA_TVNORMS_H
> > +#define _DT_BINDINGS_MEDIA_TVNORMS_H
> > +
> > +/* one bit for each */
> > +#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_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)
> > +
> > +#endif /* _DT_BINDINGS_MEDIA_TVNORMS_H */

Patch looks good to me.

Thanks,
Mauro

  parent reply index

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-15 12:44 [PATCH v6 00/13] TVP5150 new features Marco Felsch
2019-04-15 12:44 ` [PATCH v6 01/13] dt-bindings: connector: analog: add tv norms property Marco Felsch
2019-05-06 10:01   ` Hans Verkuil
2019-05-06 10:06     ` Hans Verkuil
2019-05-14 18:11     ` Mauro Carvalho Chehab [this message]
2019-08-09  6:00       ` Marco Felsch
2019-05-16 16:27   ` Laurent Pinchart
2019-08-09  5:58     ` Marco Felsch
2019-08-15 12:33       ` Laurent Pinchart
2019-08-15 12:50         ` Marco Felsch
2019-08-15 13:02           ` Laurent Pinchart
2019-08-15 13:35             ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 02/13] media: v4l2-fwnode: add v4l2_fwnode_connector Marco Felsch
2019-05-06  9:50   ` Hans Verkuil
2019-05-14 18:17     ` Mauro Carvalho Chehab
2019-08-09  7:20     ` Marco Felsch
2019-05-16 16:36   ` Laurent Pinchart
2019-08-09  7:55     ` Marco Felsch
2019-08-15 12:38       ` Laurent Pinchart
2019-08-15 13:04         ` Marco Felsch
2019-08-15 13:10           ` Laurent Pinchart
2019-08-15 13:37             ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 03/13] media: v4l2-fwnode: add initial connector parsing support Marco Felsch
2019-05-06 10:10   ` Hans Verkuil
2019-05-14 18:20     ` Mauro Carvalho Chehab
2019-05-16 16:51       ` Laurent Pinchart
2019-08-09 12:16         ` Marco Felsch
2019-08-15 12:48           ` Laurent Pinchart
2019-08-15 13:14             ` Marco Felsch
2019-08-09  8:59       ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 04/13] partial revert of "[media] tvp5150: add HW input connectors support" Marco Felsch
2019-04-15 12:44 ` [PATCH v6 05/13] media: tvp5150: add input source selection of_graph support Marco Felsch
2019-05-06 10:09   ` Jacopo Mondi
2019-05-14 18:25   ` Mauro Carvalho Chehab
2019-05-16 18:03     ` Laurent Pinchart
2019-08-13  8:54       ` Marco Felsch
2019-08-15 12:51         ` Laurent Pinchart
2019-08-15 13:22           ` Marco Felsch
2019-08-15 13:26             ` Laurent Pinchart
2019-04-15 12:44 ` [PATCH v6 06/13] media: dt-bindings: tvp5150: Add input port connectors DT bindings Marco Felsch
2019-05-14 18:27   ` Mauro Carvalho Chehab
2019-05-16 18:05   ` Laurent Pinchart
2019-08-13  8:56     ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 07/13] media: tvp5150: add FORMAT_TRY support for get/set selection handlers Marco Felsch
2019-05-06 13:36   ` Jacopo Mondi
2019-08-09  5:33     ` Marco Felsch
2019-05-14 18:48   ` Mauro Carvalho Chehab
2019-08-09  5:34     ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 08/13] media: tvp5150: initialize subdev before parsing device tree Marco Felsch
2019-05-14 20:20   ` Mauro Carvalho Chehab
2019-08-09  5:42     ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 09/13] media: tvp5150: add s_power callback Marco Felsch
2019-05-14 20:13   ` Mauro Carvalho Chehab
2019-08-09  5:39     ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 10/13] media: dt-bindings: tvp5150: cleanup bindings stlye Marco Felsch
2019-04-15 12:44 ` [PATCH v6 11/13] media: dt-bindings: tvp5150: add optional tvnorms documentation Marco Felsch
2019-04-15 12:44 ` [PATCH v6 12/13] media: tvp5150: add support to limit tv norms on connector Marco Felsch
2019-05-16 18:07   ` Laurent Pinchart
2019-08-13  9:10     ` Marco Felsch
2019-08-15 12:53       ` Laurent Pinchart
2019-08-15 13:26         ` Marco Felsch
2019-04-15 12:44 ` [PATCH v6 13/13] media: tvp5150: make debug output more readable Marco Felsch
2019-05-06 13:39   ` Jacopo Mondi
2019-05-14 20:18     ` Mauro Carvalho Chehab
2019-08-09  5:42       ` Marco Felsch
2019-05-06  5:47 ` [PATCH v6 00/13] TVP5150 new features Marco Felsch
2019-05-14 17:18   ` Mauro Carvalho Chehab
2019-05-14 20:20     ` Mauro Carvalho Chehab
2019-05-14 20:58       ` Marco Felsch
2019-05-14 23:41         ` Mauro Carvalho Chehab

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