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

Mauro Carvalho Chehab
2018-08-02T09:49:00Z

Em Thu, 2 Aug 2018 10:01:01 +0200
Marco Felsch <m.felsch@pengutronix.de> escreveu:

> Hi Mauro,
>
> On 18-08-01 12:50, Mauro Carvalho Chehab wrote:
> > Em Wed, 1 Aug 2018 16:49:26 +0200
> > Marco Felsch <m.felsch@pengutronix.de> escreveu:
> >
> > > 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.
> >
> > Yes, it is a typo, but at the other line... I meant to use the register
> > 0x88, e. g.:
> >
> > regmap_read(decoder->regmap, TVP5150_STATUS_REG_1, &status);
>
> During my development I tried this status register too, as descibed on
> the community website [1]. But that wasn't that good, because the look
> will be lost very often. Bit7 of Interrupt Status Reg A (0xc0) is more
> robust for that kind of work, since it covers the whole signal.
>
> [1] http://e2e.ti.com/support/data_converters/videoconverters/f/918/p/ \
> 617120/2273276?keyMatch=tvp5150%20lock%20lost&tisearch=Search-EN-Support

Bit 4 is not reliable for such purpose, but, on my tests, when video is
present, bits 1, 2 and 3 are present when there is a proper signal.
Basically, all the times I issued a std query ioctl, it reads 0x1e.

When the signal is removed, I get a 0x00.

Here, reading int status reg A returns 0x40 with or without signal,
probably because IRQ is not enabled. See, for USB devices like em28xx,
we don't have direct access to tvp5051 IRQ line. If the IRQ lines is
somewhat wired to em28xx, it could be possible that the em28xx would
handle it, but we would need to know a way to setup em28xx to handle irqs.
I don't know if this is possible, and, if so, how em28xx would be
notifying such interrupts via some URB packet.

> >
> > I ran some tests here: the int status reg is not updated.
> >
> > Also, after thinking a little bit, I opted to not use the query_lock()
> > at s_stream. It makes no sense there without adding a status polling
> > logic. I also opted to remove initializing decoder->lock to true, as
> > this is very counter-intuitive. Instead, I'm adding a test at s_stream
> > if decoder->irq is set. This makes easier to understand the code.
>
> Yes, you're right.
>
> > Btw, on my tests here, I noticed a problem with S-Video... at least with
> > AV-350 grabber, composite is only working when S-Video is connected.
>
> Unfortunately I have only a custom board with one composite connection.
>
> >
> > This bug also happens before your patchset, so this is not a regression
> > caused by your patches.
> >
> > Anyway, patch enclosed. I added it together with my patch series at:
> >
> > https://git.linuxtv.org/mchehab/experimental.git/log/?h=tvp5150-2
>
> Did you drop the DT of_graph support patch? It was there on your first
> tvp5150 branch.

Yes. As discussed, I'm waiting for a replacement patch from you. So,
after testing, I removed it, in order to make simpler to add your
replacement patch.

IMO, the proper mapping is one input linked to (up to) 3 connectors.

Please notice that I'm also waiting for a replacement for patch 06/22
(and a rebase for the not-yet-applied patches).

Feel free to send those patches against
https://git.linuxtv.org/mchehab/experimental.git/log/?h=tvp5150-3

(no changes on tvp5051 patches here - it is just rebased on the top of
pad-fix-3 branch)

>
> >
> > I'll keep doing more tests here.
> >
> > >
> > > > +}
> > > > +
> > > > 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);
> > > >
> > > >
> > > >
> >
> > [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.
> >
> > 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 efc441df7cac..e74af68be2eb 100644
> > --- a/drivers/media/i2c/tvp5150.c
> > +++ b/drivers/media/i2c/tvp5150.c
> > @@ -810,11 +810,25 @@ 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(decoder->regmap, TVP5150_STATUS_REG_1, &status);
> > +
> > + /* For standard detection, we need the 3 locks */
> > + return (status & 0x0e) == 0x0e;
> > +}
> > +
> > static int tvp5150_querystd(struct v4l2_subdev *sd, v4l2_std_id *std_id)
> > {
> > struct tvp5150 *decoder = to_tvp5150(sd);
>
> We should drop the decoder var here and not in the cleanup patch "media:
> tvp5150: get rid of some warnings".

I don't like the idea of merging stuff with different things together.
One patch per logical change.

> There are always two version of the
> patch that remove the 'static' warning [2,3].
>
> [2] https://www.spinics.net/lists/linux-media/msg138318.html
> [3] https://www.spinics.net/lists/linux-media/msg138363.html

I'll likely just fold the static change with the patch that added
the warning when applying mainstream, adding a notice there at the
patch's description.

>
> Regards,
> Marco
> >
> > - *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;
> > }
> > @@ -1208,7 +1222,10 @@ 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;
> > + if (decoder->irq)
> > + val = decoder->lock ? decoder->oe : 0;
> > + else
> > + val = decoder->oe;
> > int_val = TVP5150_INT_A_LOCK;
> > v4l2_subdev_notify_event(&decoder->sd, &tvp5150_ev_fmt);
> > }
> > @@ -1777,8 +1794,6 @@ 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);
> >
> >
> >
> > Thanks,
> > Mauro
> >
>

Thanks,
Mauro