From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v7 01/13] dt-bindings: connector: analog: add tv norms property References: <20190815115747.24018-1-m.felsch@pengutronix.de> <20190815115747.24018-2-m.felsch@pengutronix.de> <76aeaa4e-4a29-5abe-1af6-fc82958e9530@xs4all.nl> <20190819080904.ch3e3by5seha5ca7@pengutronix.de> From: Hans Verkuil Message-ID: <14e1593c-0d90-f242-9ab9-598a1005dbb8@xs4all.nl> Date: Mon, 19 Aug 2019 10:39:59 +0200 MIME-Version: 1.0 In-Reply-To: <20190819080904.ch3e3by5seha5ca7@pengutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit To: Marco Felsch Cc: mchehab@kernel.org, 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 List-ID: On 8/19/19 10:09 AM, Marco Felsch wrote: > 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 >>> Reviewed-by: Rob Herring >>> --- >>> [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. It's a bit of both, actually. But in the context of S-Video and Composite connectors it is a video standard. In the context of a tuner/modulator it would be a TV standard. I.e. there is no difference between PAL_B and PAL_[GHIDJ] when it comes to S-Video and Composite connectors, but in the context of a tuner/modulator these defines give additional information about transmission bands, etc. That said, I think video-standards is too vague, but so is tv-standards. How about sdtv-standards? I think that makes a lot of sense since this is really just for SDTV. So tvnorms.h becomes sdtv-standards.h. > >> '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 >>> + */ >>> + >>> +#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. Move it to display: that matches where the documentation is. Note that this means that _DT_BINDINGS_MEDIA_TVNORMS_H also becomes _DT_BINDINGS_DISPLAY_TVNORMS_H (or DISPLAY_SDTV_STANDARDS_H). Regards, Hans > > [1] drivers/gpu/drm/radeon/radeon_mode.h. > > Regards, > Marco > >> Regards, >> >> Hans >> >