On Fri Dec 13, 2024 at 12:02 PM CET, Vladimir Zapolskiy wrote:
> On 12/9/24 14:32, Bryan O'Donoghue wrote:
> > On 09/12/2024 12:01, Luca Weiss wrote:
> >> Currently the Qualcomm CAMSS driver only supports D-PHY while the
> >> hardware on most SoCs also supports C-PHY. Until this support is added,
> >> check for D-PHY to make it somewhat explicit that C-PHY won't work.
> >>
> >> Signed-off-by: Luca Weiss <luca.weiss@xxxxxxxxxxxxx>
> >> ---
> >> drivers/media/platform/qcom/camss/camss.c | 9 +++++++++
> >> 1 file changed, 9 insertions(+)
> >>
> >> diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> >> index 9fb31f4c18adee886cd0bcf84438a8f27635e07f..b99af35074cdf6fa794a0d2f0d54ecf12ac354d9 100644
> >> --- a/drivers/media/platform/qcom/camss/camss.c
> >> +++ b/drivers/media/platform/qcom/camss/camss.c
> >> @@ -1855,6 +1855,15 @@ static int camss_of_parse_endpoint_node(struct device *dev,
> >> if (ret)
> >> return ret;
> >>
> >> + /*
> >> + * Most SoCs support both D-PHY and C-PHY standards, but currently only
> >> + * D-PHY is supported in the driver.
> >> + */
> >> + if (vep.bus_type != V4L2_MBUS_CSI2_DPHY) {
> >> + dev_err(dev, "Unsupported bus type %d\n", vep.bus_type);
> >> + return -EINVAL;
> >> + }
> >> +
>
> Looks like it would break all old board dtbs, which is not just bad, but NAK.
>
> V4L2_MBUS_UNKNOWN shall be properly handled without the risk of regressions.
Please see drivers/media/v4l2-core/v4l2-fwnode.c around line 218.
The code there sets bus_type if it's UNKNOWN
if (bus_type == V4L2_MBUS_UNKNOWN)
vep->bus_type = V4L2_MBUS_CSI2_DPHY;
So setting "bus-type" in dt is not necessary, even if it makes things
more explicit from dt side. I don't think we'll ever get UNKNOWN here in
camss.
Regards
Luca
>
> >> csd->interface.csiphy_id = vep.base.port;
> >>
> >> mipi_csi2 = &vep.bus.mipi_csi2;
> >>
> >
> > Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> >
>
> --
> Best wishes,
> Vladimir
