Re: [PATCH v1 1/2] arm64: dts: imx8mp: Add CSIS DT nodes

[Adam Ford <aford173@gmail.com>]

On Mon, Apr 17, 2023 at 5:11 AM Alexander Stein
<alexander.stein@ew.tq-group.com> wrote:
>
> Am Montag, 17. April 2023, 10:15:10 CEST schrieb Laurent Pinchart:
> > Hi Marco,
> >
> > On Mon, Apr 17, 2023 at 10:01:17AM +0200, Marco Felsch wrote:
> > > On 23-04-17, Laurent Pinchart wrote:
> > > > On Mon, Apr 17, 2023 at 08:50:59AM +0200, Marco Felsch wrote:
> > > > > Hi Laurent,
> > > > >
> > > > > your patch LGTM just one nit/idea, please see below.
> > > > >
> > > > > On 23-04-17, Laurent Pinchart wrote:
> > > > > > Add DT nodes for the two CSI-2 receivers of the i.MX8MP.
> > > > > >
> > > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > > > ---
> > > > > >
> > > > > >  arch/arm64/boot/dts/freescale/imx8mp.dtsi | 60
> > > > > >  +++++++++++++++++++++++
> > > > > >  1 file changed, 60 insertions(+)
> > > > > >
> > > > > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> > > > > > b/arch/arm64/boot/dts/freescale/imx8mp.dtsi index
> > > > > > 2dd60e3252f3..2a374a4c14a2 100644
> > > > > > --- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> > > > > > +++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
> > > > > > @@ -1239,6 +1239,66 @@ ldb_lvds_ch1: endpoint {
> > > > > >
> > > > > >                               };
> > > > > >
> > > > > >                       };
> > > > > >
> > > > > > +                     mipi_csi_0: csi@32e40000 {
> > > > > > +                             compatible = "fsl,imx8mp-
> mipi-csi2", "fsl,imx8mm-mipi-csi2";
> > > > > > +                             reg = <0x32e40000 0x10000>;
> > > > > > +                             interrupts = <GIC_SPI 17
> IRQ_TYPE_LEVEL_HIGH>;
> > > > > > +                             clock-frequency =
> <500000000>;
> > > > > > +                             clocks = <&clk
> IMX8MP_CLK_MEDIA_APB_ROOT>,
> > > > > > +                                      <&clk
> IMX8MP_CLK_MEDIA_CAM1_PIX_ROOT>,
> > > > > > +                                      <&clk
> IMX8MP_CLK_MEDIA_MIPI_PHY1_REF_ROOT>,
> > > > > > +                                      <&clk
> IMX8MP_CLK_MEDIA_AXI_ROOT>;
> > > > > > +                             clock-names = "pclk",
> "wrap", "phy", "axi";
> > > > > > +                             assigned-clocks = <&clk
> IMX8MP_CLK_MEDIA_CAM1_PIX>;
> > > > > > +                             assigned-clock-parents =
> <&clk IMX8MP_SYS_PLL2_1000M>;
> > > > > > +                             assigned-clock-rates =
> <500000000>;
> > > > > > +                             power-domains =
> <&media_blk_ctrl
> > > > > > IMX8MP_MEDIABLK_PD_MIPI_CSI2_1>;
> > > > > > +                             status = "disabled";
> > > > > > +
> > > > > > +                             ports {
> > > > > > +                                     #address-cells =
> <1>;
> > > > > > +                                     #size-cells = <0>;
> > > > > > +
> > > > > > +                                     port@0 {
> > > > > > +                                             reg =
> <0>;
> > > > >
> > > > > If we would add:
> > > > >                                                 mipi_csi_0_in:
> endpoint {};
> > > > >
> > > > > here we could refernce it from overlays/board dts files more easily.
> > > >
> > > > Isn't there an unwritten rule (or consensus) that an endpoint should
> > > > always have a remote-endpoint property ?
> > >
> > > I don't know if there is one.
> > >
> > > > While ports describe hardware properties of a device and should always
> > > > be there regardless of connections, endpoints describe connections and
> > > > I don't think they should be instantiated with a valid
> > > > remote-endpoint.
> > >
> > > I know, therefore I mentioned it as idea to make it 'easier' to add
> > > camera nodes.
> >
> > As a middleground, would it be useful to have a label for the port ?
> > Something like
> >
> >       mipi_csi_0: csi@32e40000 {
> >               ports {
> >                       mipi_csi_0_port_0: port@0 {
> >                       };
> >               };
> >       };
> >
> > An overlay could then reference that and create the endpoint. I'm not
> > entirely sure how useful that would be though, as the overlay would need
> > to enable the CSI node anyway. Compare
> >
> > --------
> > &mipi_csi_0 {
> >       status = "okay";
> > };
> >
> > &mipi_csi_0_port_0 {
> >       mipi_csi_0_in: endpoint {
> >               remote-endpoint = <&imx327_out>;
> >       };
> > };
> > --------
> >
> > with
> >
> > --------
> > &mipi_csi_0 {
> >       status = "okay";
> >
> >       ports {
> >               port@0 {
> >                       mipi_csi_0_in: endpoint {
> >                               remote-endpoint = <&imx327_out>;
> >                       };
> >               };
> >       };
> > };
> > --------
> >
> > I have a slight preference for the latter as it groups all the CSI0 data
> > in a single overlay target, but if the former is generally preferred,
> > I'm fine with that too.
>
> The former is more compact, but also raises the following dtc warnings while
> creating the .dtbo:
> Warning (graph_endpoint): /fragment@4/__overlay__: graph endpoint node name
> should be 'endpoint'
> Warning (graph_endpoint): /fragment@4/__overlay__: graph connection to node '/
> fragment@1/__overlay__/ports/port@1/endpoint' is not bidirectional
>
> for the following snippet:
>
> &mipi_csi_0_out {
>         remote-endpoint = <&isp1_in>;
> };
>
> I'm not sure if there is a chance to fix at all.

Once there is consensus on how this should be generically plumbed,
please keep me in the loop, so I can add the corresponding imx8m Nano
trees as well.  I've tested Laurent's work for a while on the Nano
that I have.  I was going to push DT updates for Nano, then I saw this
conversation, so I decided to hold off for now.

adam
>
> Best regards,
> Alexander
>
> >
> > > > > > +                                     };
> > > > > > +
> > > > > > +                                     port@1 {
> > > > > > +                                             reg =
> <1>;
> > > > > > +                                     };
> > > > > > +                             };
> > > > > > +                     };
> > > > > > +
> > > > > > +                     mipi_csi_1: csi@32e50000 {
> > > > > > +                             compatible = "fsl,imx8mp-
> mipi-csi2", "fsl,imx8mm-mipi-csi2";
> > > > > > +                             reg = <0x32e50000 0x10000>;
> > > > > > +                             interrupts = <GIC_SPI 80
> IRQ_TYPE_LEVEL_HIGH>;
> > > > > > +                             clock-frequency =
> <266000000>;
> > > > > > +                             clocks = <&clk
> IMX8MP_CLK_MEDIA_APB_ROOT>,
> > > > > > +                                      <&clk
> IMX8MP_CLK_MEDIA_CAM2_PIX_ROOT>,
> > > > > > +                                      <&clk
> IMX8MP_CLK_MEDIA_MIPI_PHY1_REF_ROOT>,
> > > > > > +                                      <&clk
> IMX8MP_CLK_MEDIA_AXI_ROOT>;
> > > > > > +                             clock-names = "pclk",
> "wrap", "phy", "axi";
> > > > > > +                             assigned-clocks = <&clk
> IMX8MP_CLK_MEDIA_CAM2_PIX>;
> > > > > > +                             assigned-clock-parents =
> <&clk IMX8MP_SYS_PLL2_1000M>;
> > > > > > +                             assigned-clock-rates =
> <266000000>;
> > > > > > +                             power-domains =
> <&media_blk_ctrl
> > > > > > IMX8MP_MEDIABLK_PD_MIPI_CSI2_2>;
> > > > > > +                             status = "disabled";
> > > > > > +
> > > > > > +                             ports {
> > > > > > +                                     #address-cells =
> <1>;
> > > > > > +                                     #size-cells = <0>;
> > > > > > +
> > > > > > +                                     port@0 {
> > > > > > +                                             reg =
> <0>;
> > > > > > +                                     };
> > > > > > +
> > > > > > +                                     port@1 {
> > > > > > +                                             reg =
> <1>;
> > > > > > +                                     };
> > > > > > +                             };
> > > > > > +                     };
> > > > > > +
> > > > > >
> > > > > >                       pcie_phy: pcie-phy@32f00000 {
> > > > > >
> > > > > >                               compatible = "fsl,imx8mp-
> pcie-phy";
> > > > > >                               reg = <0x32f00000 0x10000>;
>
>
> --
> TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
> Amtsgericht München, HRB 105018
> Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
> http://www.tq-group.com/
>
>