Re: [PATCH 16/22] [media] tvp5150: add querystd

[Marco Felsch <m.felsch@pengutronix.de>]

Hi Mauro,

On 18-08-01 11:22, Mauro Carvalho Chehab wrote:
> Em Wed, 1 Aug 2018 15:21:25 +0200
> Marco Felsch <m.felsch@pengutronix.de> escreveu:
> 
> > Hi Mauro,
> > 
> > On 18-07-30 15:09, Mauro Carvalho Chehab wrote:
> > > Em Thu, 28 Jun 2018 18:20:48 +0200
> > > Marco Felsch <m.felsch@pengutronix.de> escreveu:
> > >   
> > > > From: Philipp Zabel <p.zabel@pengutronix.de>
> > > > 
> > > > Add the querystd video_op and make it return V4L2_STD_UNKNOWN while the
> > > > TVP5150 is not locked to a signal.
> > > > 
> > > > Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
> > > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > > > ---
> > > >  drivers/media/i2c/tvp5150.c | 10 ++++++++++
> > > >  1 file changed, 10 insertions(+)
> > > > 
> > > > diff --git a/drivers/media/i2c/tvp5150.c b/drivers/media/i2c/tvp5150.c
> > > > index 99d887936ea0..1990aaa17749 100644
> > > > --- a/drivers/media/i2c/tvp5150.c
> > > > +++ b/drivers/media/i2c/tvp5150.c
> > > > @@ -796,6 +796,15 @@ static v4l2_std_id tvp5150_read_std(struct v4l2_subdev *sd)
> > > >  	}
> > > >  }
> > > >  
> > > > +static int tvp5150_querystd(struct v4l2_subdev *sd, v4l2_std_id *std_id)
> > > > +{
> > > > +	struct tvp5150 *decoder = to_tvp5150(sd);
> > > > +
> > > > +	*std_id = decoder->lock ? tvp5150_read_std(sd) : V4L2_STD_UNKNOWN;  
> > > 
> > > This patch requires rework. What happens when a device doesn't have
> > > IRQ enabled? Perhaps it should, instead, read some register in order
> > > to check for the locking status, as this would work on both cases.  
> > 
> > If IRQ isn't enabled, decoder->lock is set to always true during
> > probe(). So this case should be fine.
> 
> Not sure if tvp5150_read_std() will do the right thing. If it does,
> the above could simply be:
> 	std_id = tvp5150_read_std(sd);
> 
> But, as there are 3 variants of this chipset, it sounds safer to check
> if the device is locked before calling tvp5150_read_std().

Yes, I'm with you.

> 
> IMHO, the best would be to have a patch like the one below.
> 
> Regards,
> Mauro
> 
> [PATCH] media: tvp5150: implement decoder lock when irq is not used
> 
> When irq is used, the lock is set via IRQ code. When it isn't,
> the driver just assumes it is always locked. Instead, read the
> lock status from the status register.

Yes, that is a better solution.

> 
> Compile-tested only.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> 
> diff --git a/drivers/media/i2c/tvp5150.c b/drivers/media/i2c/tvp5150.c
> index 75e5ffc6573d..e07020d4053d 100644
> --- a/drivers/media/i2c/tvp5150.c
> +++ b/drivers/media/i2c/tvp5150.c
> @@ -811,11 +811,24 @@ static v4l2_std_id tvp5150_read_std(struct v4l2_subdev *sd)
>  	}
>  }
>  
> +static int query_lock(struct v4l2_subdev *sd)
> +{
> +	struct tvp5150 *decoder = to_tvp5150(sd);
> +	int status;
> +
> +	if (decoder->irq)
> +		return decoder->lock;
> +
> +	regmap_read(map, TVP5150_INT_STATUS_REG_A, &status);
> +
> +	return (status & 0x06) == 0x06;

Typo? It should be 0x80, as described in the datasheet (SLES209E) or
just use the TVP5150_INT_A_LOCK_STATUS define. This avoid datasheet
cross check during reading.

> +}
> +
>  static int tvp5150_querystd(struct v4l2_subdev *sd, v4l2_std_id *std_id)
>  {
>  	struct tvp5150 *decoder = to_tvp5150(sd);
>  
> -	*std_id = decoder->lock ? tvp5150_read_std(sd) : V4L2_STD_UNKNOWN;
> +	*std_id = query_lock(sd) ? tvp5150_read_std(sd) : V4L2_STD_UNKNOWN;
>  
>  	return 0;
>  }
> @@ -1247,7 +1260,7 @@ static int tvp5150_s_stream(struct v4l2_subdev *sd, int enable)
>  		tvp5150_enable(sd);
>  
>  		/* Enable outputs if decoder is locked */
> -		val = decoder->lock ? decoder->oe : 0;
> +		val = query_lock(sd) ? decoder->oe : 0;
>  		int_val = TVP5150_INT_A_LOCK;
>  		v4l2_subdev_notify_event(&decoder->sd, &tvp5150_ev_fmt);
>  	}
> @@ -1816,8 +1829,6 @@ static int tvp5150_probe(struct i2c_client *c,
>  						IRQF_ONESHOT, "tvp5150", core);
>  		if (res)
>  			return res;
> -	} else {
> -		core->lock = true;
>  	}
>  
>  	res = v4l2_async_register_subdev(sd);
> 
> 
>