Enable Modbus Climate / HVAC on/off to use the coil instead of the register(s)

[illia-piskurov]

Proposed change

The changes are necessary to add support for a range of devices such as the Haier range of air conditioners. For example, the Modbus Haier YCJ-A002 uses coil to turn on and off:

Also, there has already been an attempt and need for another person to add this functionality at this point: #121680

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes Allow Modbus Climate / HVAC on/off to use coil instead of register(s) #121680
• This PR is related to issue:
• Link to documentation pull request: Added documentation for hvac_onoff_coil (Enable Modbus Climate / HVAC on/off to use the coil instead of the registers) home-assistant.io#37082

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• I have followed the perfect PR recommendations
• The code has been formatted using Ruff (ruff format homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• [] The manifest file has all fields filled out correctly.
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• [] New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• [] For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[illia-piskurov]

Now I haven't written tests and documentation yet, because I want more experienced people to tell me if the code I wrote will work in this form. It has already been working for half a year in my production.

[crug80]

Preliminary review.
If I have correctly understood the need, this code is not able to check possible conflicts among the actual configuration (using the registers) and the new one (with coils).
As it is, an user can set a register value for both of the parameters, causing 2 simultaneous writes. the first one will use the function code 0x06 or 0x10 and in case coil is enable, it will fail. The second one will use the function code 0x1.
You have the same behaviour for a reading.

[illia-piskurov]

Preliminary review. If I have correctly understood the need, this code is not able to check possible conflicts among the actual configuration (using the registers) and the new one (with coils). As it is, an user can set a register value for both of the parameters, causing 2 simultaneous writes. the first one will use the function code 0x06 or 0x10 and in case coil is enable, it will fail. The second one will use the function code 0x1. You have the same behaviour for a reading.

I think that the old configurations will not be broken because I have not changed anything in the existing code for the registers. I used vol.Exclusive to make it impossible to specify a register and a coil at the same time.

[crug80]

I think that the old configurations will not be broken because I have not changed anything in the existing code for the registers. I used vol.Exclusive to make it impossible to specify a register and a coil at the same time.

My bad, I didn't see Exclusive.
Please add and run local tests to encourage a full review.

[illia-piskurov]

I think that the old configurations will not be broken because I have not changed anything in the existing code for the registers. I used vol.Exclusive to make it impossible to specify a register and a coil at the same time.

My bad, I didn't see Exclusive. Please add and run local tests to encourage a full review.

Added tests

[crug80]

Please:

1. align the PR with current dev branch (possible conflicts)
2. write the documentation and link it to the PR
3. Uncheck the following fields. No changes on those files in this PR
   

[illia-piskurov]

Please:

1. align the PR with current dev branch (possible conflicts)
2. write the documentation and link it to the PR
3. Uncheck the following fields. No changes on those files in this PR
   

Docs: home-assistant/home-assistant.io#37082

[illia-piskurov]

Please:

1. align the PR with current dev branch (possible conflicts)
2. write the documentation and link it to the PR
3. Uncheck the following fields. No changes on those files in this PR
   

All done

[crug80]

It seems missing a test to validate the climate update using on/off by coil.

[illia-piskurov]

It seems missing a test to validate the climate update using on/off by coil.

Done

[bdraco]

Thanks @illia-piskurov