Add support for LinkPi SmartHUB power port

[Kwiboo]

Description
LinkPi SmartHUB is a 12-port USB3.0 HUB utilizing four RTS5411 USB3.0 4-port HUB controllers, a FT232R USB UART IC and a STM32F103RB MCU for port power control. Maximum output power of each USB port is up to 15W.

Add a LinkPiSmartHUBPowerPort resource and a LinkPiSmartHUBPowerDriver with an accompanying linkpismarthub agent to support power on/off the ports of the LinkPi SmartHUB using a simple line-based protocol over a serial port.

Known commands:

• onoff <port> <1|0> - switch port power on/off
• state - get current power state of all ports
• SetOWP <1|0> <1|0> ... - set the power-on state of all ports
• GetOWP - get the power-on state of all ports

Responses are in JSON format, e.g.:

> onoff 5 1
< {"Cmd":"OnOffResp","SeqNum":1,"ret":0}
> state
< {"Cmd":"StateResp","SeqNum":2,"state":[0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0]}
> SetOWP 0 0 0 0 0 0 0 0 0 0 0 1
< {"Cmd":"SetOWPResp","SeqNum":3,"ret":0}
> GetOWP
< {"Cmd":"GetOWPResp","SeqNum":4,"owp":[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]}

A version announcement is continuously sent every second:

< {"Cmd":"VerResp","ver":"SmartHUB_<ver>","uid":"<uid>"}

Please note that the port name printed on the hub does not match the internal port index used with the commands.

Links

Information on the LinkPi SmartHUB is hard to find, following links mention it:

• https://www.yuque.com/linkpi/encoder/lpx01gqitlpfiy2q#nnyqE
• https://www.yuque.com/linkpi/encoder/rlzly3ger34w5hks

Checklist

• Documentation for the feature
• Tests for the feature
• The arguments and description in doc/configuration.rst have been updated
• PR has been tested

[codecov]

Codecov Report

❌ Patch coverage is 86.86869% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.0%. Comparing base (3912486) to head (b1bdb6c).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
labgrid/remote/exporter.py	0.0%	7 Missing ⚠️
labgrid/remote/client.py	0.0%	3 Missing ⚠️
labgrid/driver/powerdriver.py	97.4%	1 Missing ⚠️
labgrid/resource/suggest.py	0.0%	1 Missing ⚠️
labgrid/resource/udev.py	93.3%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #1729     +/-   ##
========================================
+ Coverage    45.8%   46.0%   +0.2%     
========================================
  Files         182     183      +1     
  Lines       14718   14816     +98     
========================================
+ Hits         6743    6829     +86     
- Misses       7975    7987     +12     

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3.11	46.0% <86.8%> (+0.2%)	⬆️
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3.13	46.0% <86.8%> (+0.2%)	⬆️
3.14	46.0% <86.8%> (+0.2%)	⬆️

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[Emantor]

How do we handle the case when two users want to switch different ports simultenously? Is the serial.open() already going to fail, what does the error message look like?

[Kwiboo]

I was able to trigger an error reading power status for two different ports after a few tries of parallel labgrid-client power get.

Something like following or something similar could possible happen:

Selected role main from configuration file
INFO         StepLogger:  → LinkPiSmartHUBPowerDriver.get()
INFO         StepLogger:  ⚠ LinkPiSmartHUBPowerDriver.get() [0.255s] exception=SerialException('device reports readiness to read but returned no data (device disconnected or multiple access on port?)')
Traceback (most recent call last):
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/remote/client.py", line 2304, in main
    args.func(session)
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/remote/client.py", line 980, in power
    res = getattr(drv, action)()
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/binding.py", line 102, in wrapper
    return func(self, *_args, **_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/step.py", line 215, in wrapper
    _result = func(*_args, **_kwargs)
              ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/driver/powerdriver.py", line 107, in get
    return self.proxy.get(self.port.path, self.port.index)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/util/agentwrapper.py", line 29, in __call__
    return self.wrapper.call(self.name, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/labgrid/lib/python3.12/site-packages/labgrid/util/agentwrapper.py", line 107, in call
    raise AgentException(e)
labgrid.util.agentwrapper.AgentException: SerialException('device reports readiness to read but returned no data (device disconnected or multiple access on port?)')

In above scenario there was likely two simultaneous serial.open() but only one could serial.readline() and succeeded or in worst case possible returned wrong power status.

[Kwiboo]

I was also able to trigger similar error using labgrid-client power cycle:

Selected role main from configuration file
INFO         StepLogger:  → LinkPiSmartHUBPowerDriver.cycle()
INFO         StepLogger:   → LinkPiSmartHUBPowerDriver.off()
INFO         StepLogger:   ← LinkPiSmartHUBPowerDriver.off() [0.138s]
INFO         StepLogger:   → LinkPiSmartHUBPowerDriver.on()
INFO         StepLogger:   ⚠ LinkPiSmartHUBPowerDriver.on() [1.006s] exception=SerialException('device reports readiness to read but returned no data (device disconnected or multiple access on port?)')
INFO         StepLogger:  ⚠ LinkPiSmartHUBPowerDriver.cycle() [3.145s] exception=SerialException('device reports readiness to read but returned no data (device disconnected or multiple access on port?)')