Possibility of using One Wire again

[DocHardinger]

Context

OpenWrt 22.03.

Motivation

Would be nice to use One Wire again in OpenWrt 22.03.

Description

In 18.06. One Wire is working. But in newer version of OpenWrt w1-gpio-custom has been removed. So would be great to find another solutin to use One Wire again.

Alternatives Considered

Find a way to use One Wire again

[greenbreakfast]

We'll look into this, thanks for the suggestion!

[greenbreakfast]

Note: before we go ahead with implementation, we should first do:

• Proof of concept that this is possible
• A brief description of what would changes this would entail

EDIT Sep 13, 2023:

Now that #62 enables loading device tree overlays at run time. Let's make a dt overlay package for enabling one wire on GPIO19

Example device tree overlay file for one-wire on Raspberry Pi: https://github.com/raspberrypi/linux/blob/rpi-5.15.y/arch/arm/boot/dts/overlays/w1-gpio-pullup-overlay.dts

@jempatel please work on this one next

[greenbreakfast]

Hi @jempatel
You mentioned on slack you couldn't get one-wire working in the v0.3.4 firmware. I setup a circuit and was able to read data from a DS18B20 sensor.

I followed the circuit setup from https://docs.onion.io/omega2-starter-kit/starter-kit-temp-sensor.html
And the setup and communication communication commands from: https://docs.onion.io/omega2-docs/communicating-with-1w-devices.html

root@Omega-F11D:/# insmod w1-gpio-custom bus0=0,19,0
[  114.622438] Custom GPIO-based W1 driver version 0.1.1
root@Omega-F11D:/# [  114.667490] w1_master_driver w1_bus_master1: Attaching one wire slave 28.00000f9ca41e crc d6

root@Omega-F11D:/# ll /sys/devices/w1_bus_master1/w1_master_slave_count
-r--r--r--    1 root     root          4096 Jun 28 20:22 /sys/devices/w1_bus_master1/w1_master_slave_count
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/w1_master_slave_count
1
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/w1_master_slaves
28-00000f9ca41e
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/w1_slave
9f 01 4b 46 7f ff 01 10 40 : crc=40 YES
9f 01 4b 46 7f ff 01 10 40 t=25937
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/w1_slave
e5 01 4b 46 7f ff 0b 10 be : crc=be YES
e5 01 4b 46 7f ff 0b 10 be t=30312

Could you push changes to openwrt-22.03 that enable one-wire, and I'll try them out on the same circuit?

[jempatel]

Hi @jempatel You mentioned on slack you couldn't get one-wire working in the v0.3.4 firmware. I setup a circuit and was able to read data from a DS18B20 sensor.

I followed the circuit setup from https://docs.onion.io/omega2-starter-kit/starter-kit-temp-sensor.html And the setup and communication communication commands from: https://docs.onion.io/omega2-docs/communicating-with-1w-devices.html

root@Omega-F11D:/# insmod w1-gpio-custom bus0=0,19,0
[  114.622438] Custom GPIO-based W1 driver version 0.1.1
root@Omega-F11D:/# [  114.667490] w1_master_driver w1_bus_master1: Attaching one wire slave 28.00000f9ca41e crc d6

root@Omega-F11D:/# ll /sys/devices/w1_bus_master1/w1_master_slave_count
-r--r--r--    1 root     root          4096 Jun 28 20:22 /sys/devices/w1_bus_master1/w1_master_slave_count
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/w1_master_slave_count
1
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/w1_master_slaves
28-00000f9ca41e
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/w1_slave
9f 01 4b 46 7f ff 01 10 40 : crc=40 YES
9f 01 4b 46 7f ff 01 10 40 t=25937
root@Omega-F11D:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/w1_slave
e5 01 4b 46 7f ff 0b 10 be : crc=be YES
e5 01 4b 46 7f ff 0b 10 be t=30312

Could you push changes to openwrt-22.03 that enable one-wire, and I'll try them out on the same circuit?

Thanks @greenbreakfast , the issue was with the jumper cable at my end, with the new jumper cable, it works fine. I am testing new changes at my end now.

[greenbreakfast]

@jempatel wanted to check in and see how's it going with one-wire
Is there a roadblock currently? Do you need any help?

[jempatel]

@jempatel wanted to check in and see how's it going with one-wire Is there a roadblock currently? Do you need any help?

Hi @greenbreakfast, Its done

I was applying changes to load dtbo without rebooting omega2 after package installation. It's tested and usable now, Changes are pushed into MR: https://github.com/OnionIoT/OpenWRT-Packages/pull/75/files

[greenbreakfast]

Thanks @jempatel, I tried it out on the beta firmware and it worked great!

Can you please add some basic documentation to: https://github.com/OnionIoT/documentation/blob/main/docs/hardware-interfaces/one-wire.md

@DocHardinger Please try it out and let us know how it goes!

---

For reference, here's what I did:

opkg update
opkg install onion-dt-overlay-w1-gpio

I connected a DS18B20+ sensor to GPIO19 and got this kernel message:

[  151.107321] w1_master_driver w1_bus_master1: Attaching one wire slave 28.00000f9ca41e crc d6

Then I read the sensor data:

root@Omega-f195:/# cat /sys/devices/w1_bus_master1/w1_master_slave_count
1
root@Omega-f195:/# cat /sys/devices/w1_bus_master1/w1_master_slaves
28-00000f9ca41e
root@Omega-f195:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e
cat: read error: Is a directory
root@Omega-f195:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/
alarms       eeprom       hwmon/       resolution   uevent
conv_time    ext_power    id           subsystem/   w1_slave
driver/      features     name         temperature

root@Omega-f195:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/w1_slave
80 01 4b 46 7f ff 10 10 c6 : crc=c6 YES
80 01 4b 46 7f ff 10 10 c6 t=24000
root@Omega-f195:/# cat /sys/devices/w1_bus_master1/28-00000f9ca41e/w1_slave
d1 01 4b 46 7f ff 0f 10 6c : crc=6c YES
d1 01 4b 46 7f ff 0f 10 6c t=29062

[DocHardinger]

Great! Will check this out on the weekend

[DocHardinger]

I get these results in kernel log, but maybe there is something wrong with the hardware:

[ 1268.018639] kmodloader: loading kernel modules from /etc/modules.d/*
[ 1268.063866] Driver for 1-wire Dallas network protocol.
[ 1268.088888] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 1268.242423] kmodloader: loading kernel modules from /etc/modules.d/*
[ 1268.280732] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 1268.388775] OF: overlay: WARNING: memory leak will occur if overlay removed, property: /symbols/onewire
[ 1268.399520] gpio-499 (onewire): enforced open drain please flag it properly in DT/ACPI DSDT/board file
[ 1271.210541] w1_master_driver w1_bus_master1: w1_search: max_slave_count 64 reached, will continue next search.
[ 1322.330413] w1_master_driver w1_bus_master1: Attaching one wire slave 00.800000000000 crc 8c
[ 1322.385030] w1_master_driver w1_bus_master1: Family 0 for 00.800000000000.8c is not registered.
[ 1385.929988] w1_master_driver w1_bus_master1: Attaching one wire slave 00.400000000000 crc 46
[ 1385.986902] w1_master_driver w1_bus_master1: Family 0 for 00.400000000000.46 is not registered.
[ 1436.689212] w1_master_driver w1_bus_master1: Attaching one wire slave 00.c00000000000 crc ca
[ 1436.744394] w1_master_driver w1_bus_master1: Family 0 for 00.c00000000000.ca is not registered.
[ 1513.128770] w1_master_driver w1_bus_master1: Attaching one wire slave 00.200000000000 crc 23
[ 1513.183644] w1_master_driver w1_bus_master1: Family 0 for 00.200000000000.23 is not registered.
[ 1576.728458] w1_master_driver w1_bus_master1: Attaching one wire slave 00.a00000000000 crc af
[ 1576.784910] w1_master_driver w1_bus_master1: Family 0 for 00.a00000000000.af is not registered.
[ 1614.648265] w1_master_driver w1_bus_master1: Attaching one wire slave 00.600000000000 crc 65
[ 1614.702914] w1_master_driver w1_bus_master1: Family 0 for 00.600000000000.65 is not registered.
[ 1655.128157] w1_master_driver w1_bus_master1: Attaching one wire slave 00.e00000000000 crc e9
[ 1655.183430] w1_master_driver w1_bus_master1: Family 0 for 00.e00000000000.e9 is not registered.
[ 1718.127609] w1_master_driver w1_bus_master1: Attaching one wire slave 00.100000000000 crc 9d
[ 1718.181770] w1_master_driver w1_bus_master1: Family 0 for 00.100000000000.9d is not registered.
[ 1757.247532] w1_master_driver w1_bus_master1: Attaching one wire slave 00.900000000000 crc 11
[ 1757.301931] w1_master_driver w1_bus_master1: Family 0 for 00.900000000000.11 is not registered.
[ 1832.487417] w1_master_driver w1_bus_master1: Attaching one wire slave 00.500000000000 crc db
[ 1832.546157] w1_master_driver w1_bus_master1: Family 0 for 00.500000000000.db is not registered.
[ 1884.447198] w1_master_driver w1_bus_master1: Attaching one wire slave 00.d00000000000 crc 57
[ 1884.501606] w1_master_driver w1_bus_master1: Family 0 for 00.d00000000000.57 is not registered.

Ok my fault, i connected the sensor to GPIO 11. So its just searching for devices on GPIO19. Is it possible to change the GPIO which one wire is using, like in older firmware using insmod w1-gpio-custom bus0=0,11,0 ? Especially because we are using GPIO19 for Hardware PWM...

[greenbreakfast]

Yep, we can make that change. What GPIO would you prefer?

I would avoid GPIO11 since the bootloader will always program it to output high (https://docs.onion.io/omega2-docs/using-gpios.html#reset-led-pins)

[DocHardinger]

What about GPIO41?

[greenbreakfast]

@DocHardinger I'd like to keep this useful to both Omega2 and Omega2S users, so I'd prefer GPIOs that are pinned out on the Omega2 through-hole models as well: https://docs.onion.io/omega2-docs/omega2p.html#the-pins-1

What do you think about GPIOs 0, 1, 2, or 3?

[DocHardinger]

Sounds good!

[DocHardinger]

GPIO 2 is perfect for us!

[greenbreakfast]

Closing this issue - I've made a new issue (#76) to track changing the GPIO for the one-wire bus master.

EDIT: forgot to mention, documentation for using one-wire available at https://documentation.onioniot.com/device-tree-overlay/one-wire-devices
More news on the new documentation site coming soon