Hi Frieder,
On Tue, May 25, 2021 at 11:59:40AM +0200, Frieder Schrempf wrote:
> On 19.05.21 02:16, Laurent Pinchart wrote:
> > On Mon, May 17, 2021 at 12:21:17PM +0200, Frieder Schrempf wrote:
> >> On 16.05.21 04:42, Laurent Pinchart wrote:
> >>> Sample code from NXP, as well as experiments on i.MX8MM with RAW10
> >>> capture with an OV5640 sensor connected over CSI-2, showed that the
> >>> TWO_8BIT_SENSOR field of the CSICR3 register needs to be set for formats
> >>> larger than 8 bits. Do so, even if the reference manual doesn't clearly
> >>> describe the effect of the field.
> >>>
> >>> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >>
> >> For the ADV7280-M I also have the diffs below applied. Do you think
> >> setting BIT_MIPI_DOUBLE_CMPNT is specific to MEDIA_BUS_FMT_UYVY8_2X8?
> >
> > Do you need MEDIA_BUS_FMT_UYVY8_2X8 ? Neither MEDIA_BUS_FMT_UYVY8_1X16
> > nor MEDIA_BUS_FMT_UYVY8_2X8 match exactly how YUV 4:2:2 data is
> > transmitted over CSI-2. V4L2 uses MEDIA_BUS_FMT_UYVY8_1X16 as a
> > convention.
>
> I just use MEDIA_BUS_FMT_UYVY8_2X8 as the ADV7280 driver sets it. But
> if the convention is to use MEDIA_BUS_FMT_UYVY8_1X16 for YUV422, then
> maybe the ADV driver needs to be fixed.
That would be the ideal situation. We need to be careful about not
breaking backward compatibility, but apart from that,
MEDIA_BUS_FMT_UYVY8_1X16 is the way to go.
I started writing a documentation patch, and found it it's already
documented :-) Documentation/userspace-api/media/v4l/subdev-formats.rst
states:
The media bus pixel codes document parallel formats. Should the
pixel data be transported over a serial bus, the media bus pixel
code that describes a parallel format that transfers a sample on a
single clock cycle is used. For instance, both
MEDIA_BUS_FMT_BGR888_1X24 and MEDIA_BUS_FMT_BGR888_3X8 are used on
parallel busses for transferring an 8 bits per sample BGR data,
whereas on serial busses the data in this format is only referred to
using MEDIA_BUS_FMT_BGR888_1X24. This is because there is
effectively only a single way to transport that format on the serial
busses.
> >> In the RM it mentions YUV422 in the description of
> >> BIT_MIPI_DOUBLE_CMPNT and without setting it, the colors are all
> >> wrong.
> >
> > That's interesting. I've tested YUV 4:2:2 with an OV5640 sensor, and I
> > don't recall having to set the MIPI_DOUBLE_CMPNT field. I'll try to
> > retest.
> >
> >> I know this is not really related to this patch. I'm just wondering
> >> how to properly support my setup.
> >
> > It's hard to tell :-( The MIPI_CSI2_ISP_CONFIG PIXEL_MODE and PARALLEL
> > fields are not well documented, and neither is the CSI_CR18
> > MIPI_DOUBLE_CMPNT field. While the CSIS and the CSI bridge are
> > documented, how they're integrated isn't described. So far, I can only
> > guess.
> >
> >> --- a/drivers/staging/media/imx/imx7-mipi-csis.c
> >> +++ b/drivers/staging/media/imx/imx7-mipi-csis.c
> >> @@ -346,6 +346,11 @@ struct csis_pix_format {
> >>
> >> static const struct csis_pix_format mipi_csis_formats[] = {
> >> /* YUV formats. */
> >> + {
> >> + .code = MEDIA_BUS_FMT_UYVY8_2X8,
> >> + .data_type = MIPI_CSI2_DATA_TYPE_YUV422_8,
> >> + .width = 8,
> >> + },
> >> {
> >> .code = MEDIA_BUS_FMT_UYVY8_1X16,
> >> .data_type = MIPI_CSI2_DATA_TYPE_YUV422_8,
> >>
> >> --- a/drivers/staging/media/imx/imx7-mipi-csis.c
> >> +++ b/drivers/staging/media/imx/imx7-mipi-csis.c
> >> @@ -504,7 +504,7 @@ static void __mipi_csis_set_format(struct csi_state *state)
> >> /* Color format */
> >> val = mipi_csis_read(state, MIPI_CSIS_ISP_CONFIG_CH(0));
> >> val &= ~(MIPI_CSIS_ISPCFG_ALIGN_32BIT | MIPI_CSIS_ISPCFG_FMT_MASK);
> >> - val |= MIPI_CSIS_ISPCFG_FMT(state->csis_fmt->data_type);
> >> + val |= MIPI_CSIS_ISPCFG_FMT(state->csis_fmt->data_type) | MIPI_CSIS_ISPCFG_PIXEL_MODE_DUAL;
> >> mipi_csis_write(state, MIPI_CSIS_ISP_CONFIG_CH(0), val);
> >>
> >> /* Pixel resolution */
> >>
> >> --- a/drivers/staging/media/imx/imx7-media-csi.c
> >> +++ b/drivers/staging/media/imx/imx7-media-csi.c
> >> @@ -492,7 +492,8 @@ static void imx7_csi_configure(struct imx7_csi *csi)
> >> case MEDIA_BUS_FMT_UYVY8_1X16:
> >> case MEDIA_BUS_FMT_YUYV8_2X8:
> >> case MEDIA_BUS_FMT_YUYV8_1X16:
> >> - cr18 |= BIT_MIPI_DATA_FORMAT_YUV422_8B;
> >> + cr3 |= BIT_TWO_8BIT_SENSOR;
> >> + cr18 |= BIT_MIPI_DATA_FORMAT_YUV422_8B | BIT_MIPI_DOUBLE_CMPNT;
> >
> > I notice that you set both PIXEL_MODE_DUAL and MIPI_DOUBLE_CMPNT. Have
> > you tried setting neither ?
>
> Yes, but as soon as I don't set PIXEL_MODE_DUAL, I get overflow errors
> from the MIPI CSI2 controller and it doesn't work at all.
What PIXEL_MODE_DUAL and MIPI_DOUBLE_CMPNT do exactly is not totally
clear, we'll have to iron it out to ensure drivers can pick the right
settings automatically.
> > Have you also tried using MEDIA_BUS_FMT_UYVY8_1X16 ? The difference
> > between MEDIA_BUS_FMT_UYVY8_2X8 and MEDIA_BUS_FMT_UYVY8_1X16 in this
> > driver is the width value passed to v4l2_get_link_freq(). With
> > MEDIA_BUS_FMT_UYVY8_2X8 you'll end up with a computed link frequency
> > equal to half of the actual value, and thus a wrong Ths_settle value. It
> > shuold have no other influence though.
>
> The link frequency calculation doesn't work for me at the moment, as
> the ADV driver doesn't provide any of the controls V4L2_CID_LINK_FREQ
> or V4L2_CID_PIXEL_RATE. So for now I just hardcoded the Ths_settle
> value.
--
Regards,
Laurent Pinchart
