fan_control: add FindClusterOnEndpoint wrapper

[dietolive-tw]

fan_control: add FindClusterOnEndpoint wrapper

The flow_measurement and relative_humidity_measurement integration.cpp files provide a namespace-level FindClusterOnEndpoint() wrapper so application code can access the codegen cluster instance and call methods like SetPercentCurrent() directly. fan_control was missing this wrapper.

The upstream CodegenIntegration.h declares FindClusterOnEndpoint(), but the matching CodegenIntegration.cpp is excluded from the esp-matter build by CMakeLists.txt (EXCLUDE_SRCS_LIST for Codegen*.cpp). Without this wrapper in integration.cpp (the file actually compiled), app code that calls FindClusterOnEndpoint gets a link error.

Add it following the flow_measurement pattern.

Refs: pattern from clusters/flow_measurement/integration.cpp

Description

fan_control was missing the namespace-level FindClusterOnEndpoint()
wrapper that flow_measurement and relative_humidity_measurement
already provide in their integration.cpp files.

The upstream CodegenIntegration.h declares FindClusterOnEndpoint(),
but the matching CodegenIntegration.cpp is excluded from the esp-matter
build by CMakeLists.txt (EXCLUDE_SRCS_LIST for Codegen*.cpp).
Without this wrapper in integration.cpp (the file actually compiled),
application code that calls FanControl::FindClusterOnEndpoint() gets
a link error.

This matters for FanControl specifically because of the
PercentCurrent attribute.
FanControlCluster::ApplyFanModeSideEffects() (in connectedhomeip)
updates mFanMode and mPercentSetting for all modes but only updates
mPercentCurrent for kOff. For non-Off modes the spec leaves
PercentCurrent to the application, which must call
SetPercentCurrent() on the cluster instance — and that requires
FindClusterOnEndpoint().

PercentCurrent is non-writable, so writing it via
esp_matter::attribute::update() desyncs the two stores: it writes
the esp-matter storage, but ReadAttribute reads from the codegen
mPercentCurrent. The codegen SetPercentCurrent() is the only
correct path, and this wrapper is what makes it reachable from
application code.

Changes

• components/esp_matter/data_model_provider/clusters/fan_control/integration.cpp
  • Add FindClusterOnEndpoint(EndpointId) (matches flow_measurement pattern)

FanControlCluster * FindClusterOnEndpoint(EndpointId endpointId)
{
    auto it = gServers.find(endpointId);
    if (it == gServers.end() || !it->second.server.IsConstructed()) {
        return nullptr;
    }
    return &it->second.server.Cluster();
}

Note: fan_control uses it->second.server.IsConstructed() /
it->second.server.Cluster() (the server member), whereas the
measurement clusters use it->second.IsConstructed() /
it->second.Cluster() directly. The wrapper matches the existing access
pattern already used by SetDefaultDelegate() in the same file.

Related

• Pattern source: components/esp_matter/data_model_provider/clusters/flow_measurement/integration.cpp
• Pattern source: components/esp_matter/data_model_provider/clusters/relative_humidity_measurement/integration.cpp
• Build exclusion: components/esp_matter/data_model_provider/CMakeLists.txt (EXCLUDE_SRCS_LIST for Codegen*.cpp)
• Related upstream code: connectedhomeip/src/app/clusters/fan-control-server/FanControlCluster.cpp (ApplyFanModeSideEffects)

Testing

• Pattern matches existing flow_measurement/integration.cpp and
  relative_humidity_measurement/integration.cpp — no behavior change for
  apps that do not call the new wrapper.
• Access pattern (it->second.server.*) matches the existing
  SetDefaultDelegate() in the same file, so the existing gServers map
  layout is respected.
• Build verified with an out-of-tree ESP-IDF + esp-matter example that
  calls FanControl::SetPercentCurrent(); without this wrapper the link
  step fails with an undefined reference to
  FindClusterOnEndpoint(EndpointId), with it the link succeeds and the
  PercentCurrent attribute reads back the value set via the codegen path
  (verified against Apple Home's fan speed UI).

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

[CLAassistant]

All committers have signed the CLA.

[shubhamdp]

@dietolive-tw could you please sign the CLA.