Adding custom entry to i2c@c240000 in device tree source

[ajellisuk]

Hello

I am trying to add support for an ADV748x IC to my application using a TX2 NX,

I tried creating my own dtsi file which contains the following block of code:

i2c@c240000 {
			video-receiver@71 {
				compatible = "adi,adv7481";
				reg = <0x70 0x71 0x72 0x73 0x74 0x75
		   			   0x60 0x61 0x62 0x63 0x64 0x65>;
			
				reg-names = "main", "dpll", "cp", "hdmi", "edid", "repeater",
					    "infoframe", "cbus", "cec", "sdp", "txa", "txb";

				#address-cells = <1>;
				#size-cells = <0>;
								
				port@7 {
				reg = <7>;

					adv7482_ain7: endpoint {
				
					};
				};

				port@8 {
					reg = <8>;

					adv7481_hdmi: endpoint {
						remote-endpoint = <&hdmi_in_con>;
					};	
				};

				port@a {
					reg = <10>;
					adv7481_out0: endpoint {
						bus-width = <4>;
						clock-lanes = <0>;
						data-lanes = <1 2 3 4>;
						remote-endpoint = <&adv_csi_in2>;
					};
				};

				port@b {
					reg = <11>;

					adv7482_txb: endpoint {
						clock-lanes = <0>;
						data-lanes = <1>;
						//remote-endpoint = <&csi20_in>;
					};
				};
			};
		};

When I loaded the driver, I noted that no device nodes, and endpoints were created.

I decompiled the resultant device tree and noted the my entry for video-receiver@71 in i2c@c240000 was missing. I added my entry for video-receiver@71, and recompiled the device tree, and after rebooting and then loading the driver noted that the device driver was creating endpoints.

My question is what to I need to do with the device tree source for the TX2 NX to make sure that it includes my entry for video-receiver@71? If I add spurious charactors to my code, the device tree fails with an error as expected, so I know it’s including my dtsi file and parsing it.

Thanks in advance

Andrew

[ShaneCCC]

It’s could be didn’t include your dts to correct file.

[ajellisuk]

Thanks for your reply.

I have delibrately put some spurious characters inside my dtsi file in the i2c@c240000, and as expected the build failed. This proves that my dtsi file is being included, but it is then being overridden later on.

I have uploaded my dtsi file for reference.

my_adv_7481.dtsi (2.5 KB)

[ShaneCCC]

Which file to include your dts?

[ajellisuk]

My dts file is included in:

hardware/nvidia/platform/t18x/lanai/kernel-dts/tegra186-p3636-0001-p3509-0000-a01.dts

[ShaneCCC]

Could you check the dmesg | grep -i kernel to check which dts should be

[ajellisuk]

[ 0.181283] DTS File Name: arch/arm64/boot/dts/…/…/…/…/…/…/hardware/nvidia/platform/t18x/lanai/kernel-dts/tegra186-p3636-0001-p3509-0000-a01.dts

[ShaneCCC]

You may need to remove nvcsi/vi in others dts file it also the in the plugin manager dts file to avoid it been overrides.

[ajellisuk]

To provide an update, and hopefully to benefit anyone else who may come across this post, I have resolved the issue.

There were a couple of problems. The first one was the line in
tegra186-p3636-0001-p3509-0000-a01.dts:

include “common/tegra186-super-module-e2614-p3509-0000-a00.dtsi”

The above dtsi was overwrinting my dtsi file.

The second problem was inside my dtsi file. My entry for i2c@c240000 was inside host1x so it was not being spliced into i2c@c240000 and therefore not being parsed by the driver.