J722SXH01EVM: 'Unsupported media bus type' when probing dummy CSI2 sensor

Tool/software:

Hi,

I am trying to add a 'dummy' sensor that just receives CSI-2 data without any configuration over I2C, based on this IMX219-based reference: https://github.com/raspberrypi/linux/pull/4226/

Background

1. Added the sensor driver source code to drivers/media/i2c/dummy_sensor.c, based on the reference driver
   1. Added sensor_get_frame_desc function based on the TI IMX219 driver

2. Add the sensor configuration in drivers/media/i2c/Kconfig:

   ...
   	  IMX214 camera.
   
   	  To compile this driver as a module, choose M here: the
   	  module will be called imx214.
   
   config VIDEO_IMX219
   	tristate "Sony IMX219 sensor support"
   	select V4L2_CCI_I2C
   	help
   	  This is a Video4Linux2 sensor driver for the Sony
   	  IMX219 camera.
   
   	  To compile this driver as a module, choose M here: the
   	  module will be called imx219.
   
   config VIDEO_IMX258
   	tristate "Sony IMX258 sensor support"
   	help
   ...

    

3. Enable the compilation of the sensor driver in drivers/media/i2c/Makefile:

   ...
   obj-$(CONFIG_VIDEO_S5C73M3) += s5c73m3/
   obj-$(CONFIG_VIDEO_S5K5BAF) += s5k5baf.o
   obj-$(CONFIG_VIDEO_DUMMY_SENSOR) += dummy_sensor.o
   obj-$(CONFIG_VIDEO_S5K6A3) += s5k6a3.o
   obj-$(CONFIG_VIDEO_SAA6588) += saa6588.o
   ...

4. Enable the kernel module for the sensor in arch/arm64/configs/defconfig:

   ...
   CONFIG_CORESIGHT_CTI=m
   CONFIG_MEMTEST=y
   CONFIG_VIDEO_DUMMY_SENSOR=m
   

5. Create a device tree overlay for the sensor and add it to arch/arm64/boot/dts/ti:

   // SPDX-License-Identifier: GPL-2.0-only
   // Definitions for Dummy CSI2 sensor
   /dts-v1/;
   /plugin/;
   
   /{
   	compatible = "brcm,bcm2835";
   
   	fragment@0 {
   		target-path = "/";
   		__overlay__ {
   			sensor: sensor {
   				compatible = "raspberrypi,dummy-csi2-sensor";
   				status = "okay";
   
   				port {
   					sensor_0: endpoint {
   						remote-endpoint = <&csi2rx0_in_sensor>;
                           bus-type = <5>; /* CSI2 DPHY */
   					};
   				};
   			};
   		};
   	};
   
   	fragment@1 {
   		target = <&csi0_port0>;
   		__overlay__ {
   			status = "okay";
   
   			port {
   				csi2rx0_in_sensor: endpoint {
   					remote-endpoint = <&sensor_0>;
                       bus-type = <5>;
   					clock-lanes = <0>;
   				};
   			};
   		};
   	};
   
   	fragment@2 {
   		target = <&csi2rx0_in_sensor>;
   		__overlay__ {
   			data-lanes = <1>;
   		};
   	};
   
       fragment@3 {
           target = <&ti_csi2rx0>;
           __overlay__ {
               status = "okay";
           };
       };
   
       fragment@4 {
           target = <&dphy0>;
           __overlay__ {
               status = "okay";
           };
       };
   
   	fragment@5 {
   		target = <&csi2rx0_in_sensor>;
   		__dormant__ {
   			data-lanes = <1 2>;
   		};
   	};
   
   	fragment@6 {
   		target = <&csi2rx0_in_sensor>;
   		__dormant__ {
   			data-lanes = <1 2 3 4>;
   		};
   	};
   
   	fragment@7 {
   		target = <&csi2rx0_in_sensor>;
   		__dormant__ {
   			clock-noncontinuous;
   		};
   	};
   
   	fragment@8 {
   		target = <&sensor_0>;
   		__overlay__ {
   			data-lanes = <1>;
   		};
   	};
   
   	fragment@9 {
   		target = <&sensor_0>;
   		__dormant__ {
   			data-lanes = <1 2>;
   		};
   	};
   
   	fragment@10 {
   		target = <&sensor_0>;
   		__dormant__ {
   			data-lanes = <1 2 3 4>;
   		};
   	};
   
   	fragment@11 {
   		target = <&sensor_0>;
   		__dormant__ {
   			clock-noncontinuous;
   		};
   	};
   
   	__overrides__ {
   		2lanes = <0>, "-2+3-6+7";
   		4lanes = <0>, "-2+4-6+8";
   		noncontinuous = <0>, "+5+9";
   	};
   };

6. Add the device tree overlay to arch/arm64/boot/dts/ti/Makefile:

   ...
   # Boards with J722s SoC
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm.dtb
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-csi2-ov5640.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-csi2-quad-rpi-cam-imx219.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-csi2-quad-tevi-ov5640.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-dsi-rpi-7inch-panel.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-fpdlink-fusion.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-microtips-mf101hie-panel.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-v3link-fusion.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-pwm.dtbo
   dtb-$(CONFIG_ARCH_K3) += k3-j722s-evm-dummy.dtbo
   ...

Problem

When I build, install, and boot the kernel with these updates, I get the following error:

root@j722s-evm:~# dmesg | grep csi
[ 8.853457] cdns-csi2rx 30101000.csi-bridge: Unsupported media bus type: 0x2
[ 8.891400] cdns-csi2rx: probe of 30101000.csi-bridge failed with error -22

The error is thrown when the cdns-csi2rx.c driver is probed, in csi2rx_parse_dt:

}

	if (v4l2_ep.bus_type != V4L2_MBUS_CSI2_DPHY) {
		dev_err(csi2rx->dev, "Unsupported media bus type: 0x%x\n",
			v4l2_ep.bus_type);
		of_node_put(ep);
		return -EINVAL;
	}

Digging into the v4l2 functions, I can't find where/why the media bus type is being initialized to 0x2. 

How can I property initialize it to V4L2_MBUS_CSI2_DPHY?

Thank you,

Jin