Hi Laurent,
Thanks for your feedback.
On 2019-03-07 02:13:18 +0200, Laurent Pinchart wrote:
> Hi Niklas,
>
> Thank you for the patch.
>
> On Sat, Feb 16, 2019 at 11:57:58PM +0100, Niklas Söderlund wrote:
> > Allow the hardware to to do proper field detection for interlaced field
> > formats by implementing s_std() and g_std(). Depending on which video
> > standard is selected the driver needs to setup the hardware to correctly
> > identify fields.
>
> I don't think this belongs to the CSI-2 receiver. Standards are really
> an analog concept, and should be handled by the analog front-end. At the
> CSI-2 level there's no concept of analog standard anymore.
I agree it should be handled by the analog front-end. This is patch just
lets the user propagate the information in the pipeline. The driver
could instead find its source subdevice in the media graph and ask which
standard it's supplying.
I wrestled a bit with this and went with this approach as it then works
the same as with other format information, such as dimensions and pixel
format. If the driver acquires the standard by itself why should it no
the same for the format? I'm willing to change this but I would like to
understand where the divider for format propagating in kernel and
user-space is :-)
Also what if there are subdevices between rcar-csi2 and the analog
front-end which do not support the g_std operation?
>
> > Later versions of the datasheet have also been updated to make it clear
> > that FLD register should be set to 0 when dealing with none interlaced
> > field formats.
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> > ---
> > drivers/media/platform/rcar-vin/rcar-csi2.c | 33 +++++++++++++++++++--
> > 1 file changed, 30 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > index f3099f3e536d808a..664d3784be2b9db9 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > @@ -361,6 +361,7 @@ struct rcar_csi2 {
> > struct v4l2_subdev *remote;
> >
> > struct v4l2_mbus_framefmt mf;
> > + v4l2_std_id std;
> >
> > struct mutex lock;
> > int stream_count;
> > @@ -389,6 +390,22 @@ static void rcsi2_write(struct rcar_csi2 *priv, unsigned int reg, u32 data)
> > iowrite32(data, priv->base + reg);
> > }
> >
> > +static int rcsi2_s_std(struct v4l2_subdev *sd, v4l2_std_id std)
> > +{
> > + struct rcar_csi2 *priv = sd_to_csi2(sd);
> > +
> > + priv->std = std;
> > + return 0;
> > +}
> > +
> > +static int rcsi2_g_std(struct v4l2_subdev *sd, v4l2_std_id *std)
> > +{
> > + struct rcar_csi2 *priv = sd_to_csi2(sd);
> > +
> > + *std = priv->std;
> > + return 0;
> > +}
> > +
> > static void rcsi2_standby_mode(struct rcar_csi2 *priv, int on)
> > {
> > if (!on) {
> > @@ -475,7 +492,7 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp)
> > static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > {
> > const struct rcar_csi2_format *format;
> > - u32 phycnt, vcdt = 0, vcdt2 = 0;
> > + u32 phycnt, vcdt = 0, vcdt2 = 0, fld = 0;
> > unsigned int i;
> > int mbps, ret;
> >
> > @@ -507,6 +524,15 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > vcdt2 |= vcdt_part << ((i % 2) * 16);
> > }
> >
> > + if (priv->mf.field != V4L2_FIELD_NONE) {
> > + fld = FLD_FLD_EN4 | FLD_FLD_EN3 | FLD_FLD_EN2 | FLD_FLD_EN;
> > +
> > + if (priv->std & V4L2_STD_525_60)
> > + fld |= FLD_FLD_NUM(2);
> > + else
> > + fld |= FLD_FLD_NUM(1);
> > + }
> > +
> > phycnt = PHYCNT_ENABLECLK;
> > phycnt |= (1 << priv->lanes) - 1;
> >
> > @@ -519,8 +545,7 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > rcsi2_write(priv, PHTC_REG, 0);
> >
> > /* Configure */
> > - rcsi2_write(priv, FLD_REG, FLD_FLD_NUM(2) | FLD_FLD_EN4 |
> > - FLD_FLD_EN3 | FLD_FLD_EN2 | FLD_FLD_EN);
> > + rcsi2_write(priv, FLD_REG, fld);
> > rcsi2_write(priv, VCDT_REG, vcdt);
> > if (vcdt2)
> > rcsi2_write(priv, VCDT2_REG, vcdt2);
> > @@ -662,6 +687,8 @@ static int rcsi2_get_pad_format(struct v4l2_subdev *sd,
> > }
> >
> > static const struct v4l2_subdev_video_ops rcar_csi2_video_ops = {
> > + .s_std = rcsi2_s_std,
> > + .g_std = rcsi2_g_std,
> > .s_stream = rcsi2_s_stream,
> > };
> >
>
> --
> Regards,
>
> Laurent Pinchart
--
Regards,
Niklas Söderlund
