Device-tree/model file changes

Joshua Park

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Sep 30, 2020, 8:22:54 PM9/30/20

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Hi all,

I'm trying to edit the /proc/device-tree/model file in the debian-10.3-iot-armhf-2020-04-06 version file system. I have tried as root and changed the permissions of the file and its parent directories but the file remains unwritable. Can anyone tell me how I am supposed to edit this file?

Dennis Lee Bieber

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Oct 1, 2020, 1:54:53 AM10/1/20

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On Wed, 30 Sep 2020 17:22:54 -0700 (PDT), in
gmane.comp.hardware.beagleboard.user Joshua Park

You don't... It doesn't exist as a file, just a virtual name in the
file system. When you read it, the OS generates the data it gives to you.
https://tldp.org/LDP/Linux-Filesystem-Hierarchy/html/proc.html

I suspect you need to edit the appropriate device tree source file,
compile it into a DTB, and install that DTB where ever u-boot is looking...

debian@beaglebone:~$ cat /proc/device-tree/model
TI AM335x BeagleBone Blackdebian@beaglebone:~$
debian@beaglebone:~$ grep -i "TI AM335x BeagleBone Black"
/opt/source/dtb-4.19-ti/src/arm/*.dts
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-audio.dts: model = "TI
AM335x BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-bbb-exp-c.dts: model = "TI
AM335x BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-bbb-exp-r.dts: model = "TI
AM335x BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-bbbmini.dts: model = "TI
AM335x BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack.dts: model = "TI AM335x
BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-roboticscape.dts: model =
"TI AM335x BeagleBone Black RoboticsCape";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-uboot.dts: model = "TI
AM335x BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-uboot-univ.dts: model =
"TI AM335x BeagleBone Black";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-wireless.dts: model = "TI
AM335x BeagleBone Black Wireless";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-wireless-roboticscape.dts:
model = "TI AM335x BeagleBone Black Wireless RoboticsCape";
/opt/source/dtb-4.19-ti/src/arm/am335x-boneblack-wl1835mod.dts: model = "TI
AM335x BeagleBone Black";
debian@beaglebone:~$

--
Dennis L Bieber

Joshua Park

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Oct 1, 2020, 10:25:50 AM10/1/20

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Ok, so what I think I need to do is make a custom DTB for my board. To build one do I just create a DTS file in the /opt/source/dtb-5.4-ti/src and run make /src/<ARCH>/custom.dts? Also to install the DTB for u-boot, I need to move the file into /boot/dtbs/$(uname -r) for debian as stated here https://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0#u-boot_dtb_search_order right?

Dennis Lee Bieber

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Oct 1, 2020, 1:45:52 PM10/1/20

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On Thu, 1 Oct 2020 07:25:50 -0700 (PDT), in

gmane.comp.hardware.beagleboard.user Joshua Park
<joshua.park0312-Re5...@public.gmane.org> wrote:

>Ok, so what I think I need to do is make a custom DTB for my board. To
>build one do I just create a DTS file in the /opt/source/dtb-5.4-ti/src and

>run *make /src/<ARCH>/custom.dts? *Also to install the DTB for u-boot, I

>need to move the file into /boot/dtbs/$(uname -r) for debian as stated here
>https://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0#u-boot_dtb_search_order
> right?

You are now beyond what I can find by Google and on-board file
searches.

--
Dennis L Bieber

Joshua Park

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Oct 1, 2020, 1:47:56 PM10/1/20

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Ok, thanks for your help.

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