Re: [PATCH 13/22] [media] tvp5150: disable output while signal not locked

Marco Felsch
2018-07-31T06:02:40Z

Hi Mauro,

thanks for your feedback.

On 18-07-30 15:00, Mauro Carvalho Chehab wrote:
> Em Thu, 28 Jun 2018 18:20:45 +0200
> Marco Felsch <m.felsch@pengutronix.de> escreveu:
>
> > From: Philipp Zabel <p.zabel@pengutronix.de>
> >
> > To avoid short frames on stream start, keep output pins at high impedance
> > while we are not properly locked onto the input signal.
> >
> > Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > ---
> > drivers/media/i2c/tvp5150.c | 39 ++++++++++++++++++++++++++-----------
> > 1 file changed, 28 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/media/i2c/tvp5150.c b/drivers/media/i2c/tvp5150.c
> > index d8bdbedd8826..27cfd08be3d2 100644
> > --- a/drivers/media/i2c/tvp5150.c
> > +++ b/drivers/media/i2c/tvp5150.c
> > @@ -60,6 +60,7 @@ struct tvp5150 {
> > v4l2_std_id detected_norm;
> > u32 input;
> > u32 output;
> > + u32 oe;
> > int enable;
> > bool lock;
> >
> > @@ -799,14 +800,20 @@ static irqreturn_t tvp5150_isr(int irq, void *dev_id)
> > {
> > struct tvp5150 *decoder = dev_id;
> > struct regmap *map = decoder->regmap;
> > - unsigned int active = 0, status = 0;
> > + unsigned int mask, active = 0, status = 0;
> > +
> > + mask = TVP5150_MISC_CTL_YCBCR_OE | TVP5150_MISC_CTL_SYNC_OE |
> > + TVP5150_MISC_CTL_CLOCK_OE;
> >
> > regmap_read(map, TVP5150_INT_STATUS_REG_A, &status);
> > if (status) {
> > regmap_write(map, TVP5150_INT_STATUS_REG_A, status);
> >
> > - if (status & TVP5150_INT_A_LOCK)
> > + if (status & TVP5150_INT_A_LOCK) {
> > decoder->lock = !!(status & TVP5150_INT_A_LOCK_STATUS);
> > + regmap_update_bits(map, TVP5150_MISC_CTL, mask,
> > + decoder->lock ? decoder->oe : 0);
> > + }
> >
> > return IRQ_HANDLED;
> > }
> > @@ -872,10 +879,26 @@ static int tvp5150_enable(struct v4l2_subdev *sd)
> > /* Disable autoswitch mode */
> > tvp5150_set_std(sd, std);
> >
> > - if (decoder->mbus_type == V4L2_MBUS_PARALLEL)
> > + /*
> > + * Enable the YCbCr and clock outputs. In discrete sync mode
> > + * (non-BT.656) additionally enable the the sync outputs.
> > + */
> > + switch (decoder->mbus_type) {
> > + case V4L2_MBUS_PARALLEL:
> > /* 8-bit 4:2:2 YUV with discrete sync output */
> > regmap_update_bits(decoder->regmap, TVP5150_DATA_RATE_SEL,
> > 0x7, 0x0);
> > + decoder->oe = TVP5150_MISC_CTL_YCBCR_OE |
> > + TVP5150_MISC_CTL_CLOCK_OE |
> > + TVP5150_MISC_CTL_SYNC_OE;
> > + break;
> > + case V4L2_MBUS_BT656:
> > + decoder->oe = TVP5150_MISC_CTL_YCBCR_OE |
> > + TVP5150_MISC_CTL_CLOCK_OE;
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> >
> > return 0;
> > };
> > @@ -1190,14 +1213,8 @@ static int tvp5150_s_stream(struct v4l2_subdev *sd, int enable)
> > if (enable) {
> > tvp5150_enable(sd);
> >
> > - /*
> > - * Enable the YCbCr and clock outputs. In discrete sync mode
> > - * (non-BT.656) additionally enable the the sync outputs.
> > - */
> > - val = TVP5150_MISC_CTL_YCBCR_OE | TVP5150_MISC_CTL_CLOCK_OE;
> > - if (decoder->mbus_type == V4L2_MBUS_PARALLEL)
> > - val |= TVP5150_MISC_CTL_SYNC_OE;
> > -
> > + /* Enable outputs if decoder is locked */
> > + val = decoder->lock ? decoder->oe : 0;
>
> Hmm... this only works if the tvp5150 has the interrupts enabled.
>
> The code should be, instead:
>
> if (c->irq)
> val = decoder->lock ? decoder->oe : 0;
> else
> val = decoder->oe;

The previous patch "[media] tvp5150: Add sync lock interrupt handling"
adds the look mechanism. As you can see the lock will be always true
if there is no interrupt support during probe():

core->irq = c->irq;
tvp5150_reset(sd, 0); /* Calls v4l2_ctrl_handler_setup() */
if (c->irq) {
res = devm_request_threaded_irq(&c->dev, c->irq,
NULL,
tvp5150_isr,
IRQF_TRIGGER_HIGH |
IRQF_ONESHOT,
"tvp5150", core);
if (res)
return res;
} else {
core->lock = true;
}

I'am with you that your s_stream version looks a bit nicer but adds the
check again.

Regards,
Marco

>
> > int_val = TVP5150_INT_A_LOCK;
> > }
> >
>
>
>
> Thanks,
> Mauro
>

--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |