On Thu, Sep 01, 2022 at 04:04:40PM +0200, Paul Kocialkowski wrote:
> Hi Laurent,
>
> On Fri 26 Aug 22, 21:59, Laurent Pinchart wrote:
> > Hi Paul,
> >
> > Thank you for the patch.
> >
> > On Fri, Aug 26, 2022 at 08:28:02PM +0200, Paul Kocialkowski wrote:
> > > MIPI CSI-2 is supported on the A83T with a dedicated controller that
> > > covers both the protocol and D-PHY. It can be connected to the CSI
> > > interface as a V4L2 subdev through the fwnode graph.
> > >
> > > This is not done by default since connecting the bridge without a
> > > subdev attached to it will cause a failure on the CSI driver.
> >
> > No urgency, but would it be possible to fix this so that the CSI-2
> > receiver can be connected to the CSI unconditionally in DT ? The
> > connection exists at the hardware level in the SoC, and should thus
> > exist here too, regardless of whether or not a sensor is connected.
>
> Yes it's true that having the link always would be legitimate.
>
> For the context, this CSI controller can be switched between the MIPI CSI-2
> controller and a parallel sensor input (i.e. it's not dedicated to one or the
> other like on the V3).
>
> Last time I tried, having the connection between the two always there resulted
> in the unability to use a parallel sensor when no sensor is attached to the
> mipi csi-2 receiver. Probably because the async notifier never completes since
> the mipi csi-2's subdev is never registered without a sensor subdev attached.
>
> Do you see a way to handle this case properly?
It sounds like an issue in the CSI-2 receiver driver. If there's no
input device attached to it, it should register its subdev directly,
without its own async notifier.
> > > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> > > ---
> > > arch/arm/boot/dts/sun8i-a83t.dtsi | 26 ++++++++++++++++++++++++++
> > > 1 file changed, 26 insertions(+)
> > >
> > > diff --git a/arch/arm/boot/dts/sun8i-a83t.dtsi b/arch/arm/boot/dts/sun8i-a83t.dtsi
> > > index 82fdb04122ca..ecf9f3b2c0c0 100644
> > > --- a/arch/arm/boot/dts/sun8i-a83t.dtsi
> > > +++ b/arch/arm/boot/dts/sun8i-a83t.dtsi
> > > @@ -1064,6 +1064,32 @@ csi: camera@1cb0000 {
> > > status = "disabled";
> > > };
> > >
> > > + mipi_csi2: csi@1cb1000 {
> > > + compatible = "allwinner,sun8i-a83t-mipi-csi2";
> > > + reg = <0x01cb1000 0x1000>;
> > > + interrupts = <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>;
> > > + clocks = <&ccu CLK_BUS_CSI>,
> > > + <&ccu CLK_CSI_SCLK>,
> > > + <&ccu CLK_MIPI_CSI>,
> > > + <&ccu CLK_CSI_MISC>;
> > > + clock-names = "bus", "mod", "mipi", "misc";
> > > + resets = <&ccu RST_BUS_CSI>;
> > > + status = "disabled";
> > > +
> > > + ports {
> > > + #address-cells = <1>;
> > > + #size-cells = <0>;
> > > +
> > > + mipi_csi2_in: port@0 {
> > > + reg = <0>;
> > > + };
> > > +
> > > + mipi_csi2_out: port@1 {
> > > + reg = <1>;
> > > + };
> > > + };
> > > + };
> > > +
> > > hdmi: hdmi@1ee0000 {
> > > compatible = "allwinner,sun8i-a83t-dw-hdmi";
> > > reg = <0x01ee0000 0x10000>;
--
Regards,
Laurent Pinchart
