[SOLVED] NanoPi NEO3 device tree overlay

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1

I am trying to get a ds18b20 1-wire temperature sensor working on my NEO3.
After I add the following line to “/boot/armbianEnv.txt” :-

overlays=w1-gpio

and reboot, I cannot SSH into the NEO3. The Network interface is down.

Watching the debug console, everything is going fine until:-

[   10.711832] OF: /onewire@0: could not get #gpio-cells for /ethernet@ff540000
[   10.712508] w1-gpio onewire@0: gpio_request_nable_pin) failed
[   10.717827] dwmmc_rockchip ff500000.mmc: error -110 requesting status
[  OK  ] Finished DietPi-PreBoot.
[  OK  ] Reached target Network (Pre).
[   10.771070] mmcblk0: recovery failed!
[   10.771551] blk_update_request: I/O error, dev mmcblk0, sector 1106512 op 0x0:(READ) flags 0x8070
         Starting Raise network interfaces...
[   10.785656] dwmmc_rockchip ff500000.mmc: error -110 requesting status
[   10.786339] mmcblk0: recovery failed!
[   10.786839] bk_update_request: I/O error, dev mmcblk0, sector 774352 op 0x0:([   10.800951] dwmms
[   10.801575] mmcblk0: recovery failed!
[   10.802160] blk_update_request: I/O error, dev mmcblk0, sector 1231280 opg 4 prio class 0
[   10.817067] dwmmc_rockchip ff500000.mmc: error -110 requesting status
[   10.817697] mmcblk0: recovery failed!
[   10.818292] blk_update_request: I/O error, dev mmcblk0, sector 1106512 opx0 phys_seg 1 prio clas0
[   10.832020] dwmmc_rockchip ff500000.mmc: error -110 requesting status
[   10.832653] mmcblk0: recovery failed!

There is more of the same, then output stops.

Remove the overlays line and everything boots fine.

Any ideas?

Also, what is the parameter for the “param_w1_pin=”
I am using GPIO Header Pin 7, which is GPIO2_A2

I have updated the “fdtfile=” line in “/boot/armbianEnv.txt” to:-

fdtfile=rockchip/rk3328-nanopi-neo3-rev02.dtb

after doing this, pwmchip0 has turned up under /sys/class/pwm/
I think this can control the fan. I’ll check this out when I get a 2-pin JST ZHN connector.

Any help appreciated.

Regards,
John

2

Hi John,

I’m looking for similar solution for NEO3 however currently got some other projects to finalize. You may check and try this one:
https://github.com/friendlyarm/WiringNP
It looks quite old (6 years) but some updates were made last year. Not sure is GPIO on NEO3 same as on NEO2 but it might be a good starting point.

Let us know results - would be nice to know it is working :slight_smile:

Mike

3

The NEO3 device tree is not available anymore with recent kernel, so with last DietPi update we switched back to a compatible NanoPi R2 one. But that may affect GPIO support: https://forum.armbian.com/topic/20133-nanopi-neo3-dtb-gone-since-linux-dtb-current-rockchip64-22021

Generally, instead of WiringPi, I’d try to use libgpiod for controlling GPIO nowadays:

apt install gpiod
4

I have solved my problem of the w1-gpio overlay not working.
I think the w1-gpio pin assigned in the supplied overlay is messing up access of the SD card.

I found some helpful information from this post:
https://forum.pine64.org/showthread.php?tid=6987&pid=100639#pid100639

I copied the overlay code, modified it to use GPIO2_A2 (pin 7 on the 26pin header), compiled it and copied the new dtbo file to “/boot/dtb/rockchip/overlay/” . Added the “overlays=w1-gpio” line to “/boot/armbianEnv.txt” and rebooted.
Success. I was able to read the ds18b20.

The steps I took:
Overlay file: rockchip-w1-gpio.dts

/dts-v1/;
/plugin/;

/ {
compatible = "rockchip,rk3328";

    fragment@0 {
            target-path = "/";
            __overlay__ {

                    w1: onewire@0 {
                            compatible = "w1-gpio";
                            pinctrl-names = "default";
                            gpios = <&gpio2 2 0>;
                            status = "okay";
                    };
            };
    };

};

You will probably need to install the device-tree-compiler.

sudo apt install device-tree-compiler

Compile the overlay:

dtc -I dts -O dtb -o rockchip-w1-gpio.dtbo  rockchip-w1-gpio.dts

Copy the compiled overlay:

sudo cp rockchip-w1-gpio.dtbo /boot/dtb/rockchip/overlay/

This will overwrite the existing “rockchip-w1-gpio.dtbo” file. If you wish to keep the original, move it to another directory or rename it.

Add the “overlays=w1-gpio” line (without quotes) to “/boot/armbianEnv.txt” and reboot.

Check that all went well by :

ls /sys/bus/w1/devices/

You should see a directory starting with “28-” . This is your ds18b20.

Read the temperature:

cat /sys/bus/w1/devices/28-xxxxxxxxxxxx/temperature

(substitute the 28-xxxxxxxxxxxx with your directory name.)

However. I came to realise that the newly created overlay will be overwritten on the next kernal update. There must be a way around this.

Further research I came across this page:
https://docs.armbian.com/User-Guide_Armbian_overlays/

This explained about a “/boot/overlay-user/” directory that is for user provided overlays.

Create the “/boot/overlay-user/” directory:

sudo mkdir /boot/overlay-user

Copy (or move) the “rockchip-w1-gpio.dbto” file from “/boot/rockchip/overlay/” to “/boot/overlay-user/” directory.

You will then need to edit “/boot/armbianEnv.txt” and add “user_overlays=rockchip-w1-gpio” (without quotes).
Comment out or remove the “overlays=w1-gpio” line, save and reboot.

You should be able to read the ds18b20 temperature as above.

I probably should have persevered to find out the correct syntax for “param_w1_pin=” but then I wouldn’t have learnt about device tree overlays etc. ( I think it might be “param_w1_pin=PC2” (GPIO2_A2))

I have upgraded to the latest DietPi and every thing is OK, although the “pwmchip0” directory has disappeared but I think I can create a device tree overlay that will bring it back. (See, the lessons are paying off.)

I have been using “python-periphery” for turning LEDs on and off but will look into libgpiod.
python-periphery:
https://github.com/vsergeev/python-periphery

pip3 install python-periphery

Regards,
John

5

Wow that is great. I’ll forward this to Armbian to have their overlay updated, or added as specific for the NanoPi NEO3.