Re: [PATCH v6 12/13] media: tvp5150: add support to limit tv norms on connector

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Marco,

On Tue, Aug 13, 2019 at 11:10:30AM +0200, Marco Felsch wrote:
> On 19-05-16 21:07, Laurent Pinchart wrote:
> > On Mon, Apr 15, 2019 at 02:44:12PM +0200, Marco Felsch wrote:
> > > The tvp5150 accepts NTSC(M,J,4.43), PAL (B,D,G,H,I,M,N) and SECAM video
> > > data and is able to auto-detect the input signal. The auto-detection
> > > does not work if the connector does not receive an input signal and the
> > > tvp5150 might not be configured correctly. This misconfiguration leads
> > > into wrong decoded video streams if the tvp5150 gets powered on before
> > > the video signal is present.
> > > 
> > > Limit the supported tv norms according to the actual selected connector
> > > to avoid a misconfiguration.
> > 
> > This seems a bit of a hack to me. In particular, on what grounds would
> > you specify a particular configuration in DT ? Also, this issue affects
> > non-DT systems, and should be solved globally.
> 
> Why is this a hack? Imagine a hardware which supports PAL signals only.
> Then it should be forbidden for the user space to configure it to SECAM
> or any NTSC. Since the hardware makes the limitation it should be
> abstracted on DT level.

What part of the hardware would be the limiting factor here ? Clearly
not the TVP5150 as it supports all TV norms, and also not the connector,
as the connector hardware doesn't care about TV norms.

> > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > > ---
> > > [1] https://patchwork.kernel.org/cover/10794703/
> > > 
> > > v5:
> > > - probe() initialize supported tv-norms according the given connectors
> > >   if they are available.
> > > - check if media-controller is used. Don't limit the norm if it isn't
> > >   used.
> > > - add more logic to be smarter during connector changing so it is
> > >   intuitiver for the user space.
> > > 
> > > v2-v4:
> > > - nothing since the patch was squashed from series [1] into this
> > >   series.
> > > 
> > >  drivers/media/i2c/tvp5150.c | 69 +++++++++++++++++++++++++++++++++++--
> > >  1 file changed, 67 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/media/i2c/tvp5150.c b/drivers/media/i2c/tvp5150.c
> > > index cd54715eb641..c0ee08546643 100644
> > > --- a/drivers/media/i2c/tvp5150.c
> > > +++ b/drivers/media/i2c/tvp5150.c
> > > @@ -32,6 +32,13 @@
> > >  #define TVP5150_MBUS_FMT	MEDIA_BUS_FMT_UYVY8_2X8
> > >  #define TVP5150_FIELD		V4L2_FIELD_ALTERNATE
> > >  #define TVP5150_COLORSPACE	V4L2_COLORSPACE_SMPTE170M
> > > +#define TVP5150_STD_MASK	(V4L2_STD_NTSC     | \
> > > +				 V4L2_STD_NTSC_443 | \
> > > +				 V4L2_STD_PAL      | \
> > > +				 V4L2_STD_PAL_M    | \
> > > +				 V4L2_STD_PAL_N    | \
> > > +				 V4L2_STD_PAL_Nc   | \
> > > +				 V4L2_STD_SECAM)
> > >  
> > >  MODULE_DESCRIPTION("Texas Instruments TVP5150A/TVP5150AM1/TVP5151 video decoder driver");
> > >  MODULE_AUTHOR("Mauro Carvalho Chehab");
> > > @@ -66,6 +73,7 @@ struct tvp5150 {
> > >  	/* media-ctl properties */
> > >  	struct media_pad pads[TVP5150_NUM_PADS];
> > >  	struct tvp5150_connector *connectors;
> > > +	struct tvp5150_connector *cur_connector;
> > >  	int connectors_num;
> > >  
> > >  	struct v4l2_ctrl_handler hdl;
> > > @@ -785,17 +793,28 @@ static int tvp5150_g_std(struct v4l2_subdev *sd, v4l2_std_id *std)
> > >  static int tvp5150_s_std(struct v4l2_subdev *sd, v4l2_std_id std)
> > >  {
> > >  	struct tvp5150 *decoder = to_tvp5150(sd);
> > > +	struct tvp5150_connector *cur_con = decoder->cur_connector;
> > > +	v4l2_std_id supported_norms = cur_con ?
> > > +		cur_con->base.connector.analog.supported_tvnorms : V4L2_STD_ALL;
> > >  
> > >  	if (decoder->norm == std)
> > >  		return 0;
> > >  
> > > +	/*
> > > +	 * check if requested std or group of std's is/are supported by the
> > > +	 * connector
> > > +	 */
> > > +	if ((supported_norms & std) == 0)
> > > +		return -EINVAL;
> > > +
> > >  	/* Change cropping height limits */
> > >  	if (std & V4L2_STD_525_60)
> > >  		decoder->rect.height = TVP5150_V_MAX_525_60;
> > >  	else
> > >  		decoder->rect.height = TVP5150_V_MAX_OTHERS;
> > >  
> > > -	decoder->norm = std;
> > > +	/* set only the specific supported std in case of group of std's */
> > > +	decoder->norm = supported_norms & std;
> > >  
> > >  	return tvp5150_set_std(sd, std);
> > >  }
> > > @@ -1347,6 +1366,8 @@ static int tvp5150_link_setup(struct media_entity *entity,
> > >  			  TVP5150_BLACK_SCREEN, 0);
> > >  
> > >  	if (flags & MEDIA_LNK_FL_ENABLED) {
> > > +		u32 new_norm;
> > > +
> > >  		/*
> > >  		 * S-Video connector is conneted to both ports AIP1A and AIP1B.
> > >  		 * Both links must be enabled in one-shot regardless which link
> > > @@ -1358,6 +1379,26 @@ static int tvp5150_link_setup(struct media_entity *entity,
> > >  			if (err)
> > >  				return err;
> > >  		}
> > > +
> > > +		/* Update the current connector */
> > > +		decoder->cur_connector =
> > > +			container_of(remote, struct tvp5150_connector, pad);
> > > +
> > > +		/*
> > > +		 * Do nothing if the new connector supports the same tv-norms as
> > > +		 * the old one.
> > > +		 */
> > > +		new_norm = decoder->norm &
> > > +			decoder->cur_connector->base.connector.analog.supported_tvnorms;
> > > +		if (decoder->norm == new_norm)
> > > +			return 0;
> > > +
> > > +		/*
> > > +		 * Fallback to the new connector tv-norms if we can't find any
> > > +		 * common between the current tv-norm and the new one.
> > > +		 */
> > > +		tvp5150_s_std(sd, new_norm ? new_norm :
> > > +			decoder->cur_connector->base.connector.analog.supported_tvnorms);
> > >  	}
> > >  
> > >  	return 0;
> > > @@ -1576,6 +1617,9 @@ static int tvp5150_registered(struct v4l2_subdev *sd)
> > >  				TVP5150_COMPOSITE1;
> > >  
> > >  			tvp5150_selmux(sd);
> > > +			decoder->cur_connector = &decoder->connectors[i];
> > > +			tvp5150_s_std(sd,
> > > +				decoder->connectors[i].base.connector.analog.supported_tvnorms);
> > >  		}
> > >  	}
> > >  #endif
> > > @@ -1903,6 +1947,11 @@ static int tvp5150_parse_dt(struct tvp5150 *decoder, struct device_node *np)
> > >  				ret = -EINVAL;
> > >  				goto err;
> > >  			}
> > > +			if (!(c.connector.analog.supported_tvnorms &
> > > +			    TVP5150_STD_MASK))
> > > +				dev_warn(dev,
> > > +					"Unsupported tv-norm on connector %s.\n",
> > > +					c.label);
> > >  			in++;
> > >  			break;
> > >  		case TVP5150_PAD_VID_OUT:
> > > @@ -2011,7 +2060,23 @@ static int tvp5150_probe(struct i2c_client *c,
> > >  	if (res < 0)
> > >  		goto err_cleanup_dt;
> > >  
> > > -	core->norm = V4L2_STD_ALL;	/* Default is autodetect */
> > > +	/*
> > > +	 * Iterate over all available connectors in case they are supported and
> > > +	 * successfully parsed. Fallback to default autodetect in case they
> > > +	 * aren't supported.
> > > +	 */
> > > +	if (core->connectors) {
> > > +		struct v4l2_fwnode_connector *con;
> > > +		int i;
> > > +
> > > +		for (i = 0; i < core->connectors_num; i++) {
> > > +			con = &core->connectors[i].base;
> > > +			core->norm |= con->connector.analog.supported_tvnorms;
> > > +		}
> > > +	} else {
> > > +		core->norm = V4L2_STD_ALL;
> > > +	}
> > > +
> > >  	core->detected_norm = V4L2_STD_UNKNOWN;
> > >  	core->input = TVP5150_COMPOSITE1;
> > >  	core->enable = true;

-- 
Regards,

Laurent Pinchart