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

[Alexander Stein <alexander.stein@ew.tq-group.com>]

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.

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>;


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