[Silabs] Air quality sensor app refactor (Auto-merged by platform-bot)

* [SL-ONLY] Air quality sensor app refactor (project-chip#973)

* initial consolidation into AppTask

* remove unused AppTask methods

* some cleanup

* remove correct unused button handler

* implement new API for sensor value get

* apply crtp

* apply override for InitAirQualitySensor

* rename GetAirQuality -> GetAirQualityValue to avoid confusion with common code

* add readme

* fix copy sources llvm build

* expose WriteAirQualityToAttribute to customer as non-override

* add missing header to readme file

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: miduggan24

examples/air-quality-sensor-app/silabs/BUILD.gn

@@ -66,6 +66,7 @@ if (wifi_soc) {
       "${examples_plat_dir}",
       "${chip_root}/src/lib",
       "${examples_common_plat_dir}",
+      "${examples_common_plat_dir}/customer",
       "${examples_common_plat_dir}/freertos_config",
     ]
 
@@ -90,6 +91,7 @@ if (wifi_soc) {
       "${examples_plat_dir}",
       "${chip_root}/src/lib",
       "${examples_common_plat_dir}",
+      "${examples_common_plat_dir}/customer",
       "${examples_common_plat_dir}/freertos_config",
     ]
 
@@ -123,9 +125,8 @@ silabs_executable("air_quality_sensor_app") {
 
   sources = [
     "${chip_root}/examples/air-quality-sensor-app/air-quality-sensor-common/src/air-quality-sensor-manager.cpp",
+    "${examples_common_plat_dir}/customer/CustomerAppTask.cpp",
     "src/AppTask.cpp",
-    "src/DataModelCallbacks.cpp",
-    "src/SensorManager.cpp",
   ]
 
   #TODO: This is a placeholder for the actual implementation

examples/air-quality-sensor-app/silabs/README.md

@@ -6,6 +6,12 @@ An example showing the use of CHIP on the Silicon Labs EFR32 MG24.
 
 -   [Matter Air Quality Sensor Example](#matter-air-quality-sensor-example)
     -   [Introduction](#introduction)
+    -   [Extending Base App Implementation](#extending-base-app-implementation)
+        -   [CustomerAppTask](#customerapptask)
+        -   [How to Override APIs](#how-to-override-apis)
+        -   [DataModelCallbacks and CustomerAppTask](#datamodelcallbacks-and-customerapptask)
+        -   [Sample Implementation](#sample-implementation)
+        -   [Override API Reference](#override-api-reference)
     -   [Building](#building)
         -   [Linux](#linux)
         -   [Mac OS X](#mac-os-x)
@@ -55,6 +61,148 @@ The air quality sensor example is intended to serve both as a means to explore
 the workings of Matter as well as a template for creating real products based on
 the Silicon Labs platform.
 
+## Extending Base App Implementation
+
+### CustomerAppTask
+
+To implement custom app behavior you can override any Silicon Labs implemented
+API in the CustomerAppTask file. This example provides
+[`CustomerAppTask.h`](../../platform/silabs/customer/CustomerAppTask.h) and
+[`CustomerAppTask.cpp`](../../platform/silabs/customer/CustomerAppTask.cpp) for
+that purpose. The base implementation and the full set of overridable `*Impl()`
+APIs live in this example's source tree under
+[`include/AppTaskImpl.h`](include/AppTaskImpl.h) and
+[`src/AppTask.cpp`](src/AppTask.cpp). Any `*Impl()` you do not override keeps
+the Silicon Labs default behavior. To customize behavior, copy
+[`CustomerAppTask.h`](../../platform/silabs/customer/CustomerAppTask.h) and
+[`CustomerAppTask.cpp`](../../platform/silabs/customer/CustomerAppTask.cpp) from
+`examples/platform/silabs/customer/` into this app's `include/` and `src/`
+folders, then update the corresponding paths in `BUILD.gn`.
+
+### How to Override APIs
+
+`CustomerAppTask` derives from the base AppTask through the Curiously Recurring
+Template Pattern (CRTP). You override only the `*Impl()` methods you need, the
+base declares one `*Impl()` per overridable API. Steps:
+
+1. Find the method to override in the base API (see
+   [Override API reference](#override-api-reference) below).
+2. Declare the same method signature in `CustomerAppTask` in your
+   `CustomerAppTask.h` under `private:`. Match the base `*Impl()` signature
+   exactly — note that `*Impl()` overrides are **non-static instance methods**
+   even when the public dispatcher (e.g. `ButtonEventHandler`) is `static`.
+3. Implement the method in `CustomerAppTask.cpp`.
+4. Build. The CRTP layer automatically routes each call to your `*Impl()` if
+   present, otherwise to the Silicon Labs default.
+
+### DataModelCallbacks and CustomerAppTask
+
+What used to live in `DataModelCallbacks.cpp` now lives in `AppTask.cpp`. The
+Matter SDK's `MatterPostAttributeChangeCallback` is implemented in
+`examples/platform/silabs/BaseApplication.cpp` and forwards to
+`AppTask::DMPostAttributeChangeCallback` (defined in `AppTask.cpp`), which you
+can customize via `DMPostAttributeChangeCallbackImpl()` in `CustomerAppTask`.
+
+Forwarding into `AppTask` still goes through CRTP as in
+[How to Override APIs](#how-to-override-apis).
+
+-   **Methods that already exist in the AppTask** — Customize them by overriding
+    the matching `*Impl()` method in `CustomerAppTask`. Do not edit the
+    `AppTask.cpp` for app-specific behavior.
+
+-   **New custom data model methods** — Add them in `CustomerAppTask` directly.
+    Do not add new application logic in autogenerated sources; those edits will
+    not survive regeneration or project upgrades.
+
+### Sample Implementation
+
+The following shows a minimal example `CustomerAppTask` that overrides
+`AppInitImpl()` and `ButtonEventHandlerImpl()`.
+
+**CustomerAppTask.h**
+
+```cpp
+#pragma once
+#include "AppTaskImpl.h"
+
+/** Minimal AppTaskImpl-derived class. Override only the *Impl() methods you need **/
+class CustomerAppTask : public AppTaskImpl<CustomerAppTask>
+{
+public:
+    static CustomerAppTask & GetAppTask() { return sAppTask; }
+
+private:
+    friend class AppTaskImpl<CustomerAppTask>;
+    CHIP_ERROR AppInitImpl();
+    void ButtonEventHandlerImpl(uint8_t button, uint8_t btnAction);
+    static CustomerAppTask sAppTask;
+};
+```
+
+**CustomerAppTask.cpp**
+
+```cpp
+#include "CustomerAppTask.h"
+#include "AppTask.h"
+#include "AppEvent.h"
+#include <platform/CHIPDeviceLayer.h>
+#include <platform/silabs/platformAbstraction/SilabsPlatform.h>
+
+#define APP_FUNCTION_BUTTON 0
+
+CustomerAppTask CustomerAppTask::sAppTask;
+
+AppTask & AppTask::GetAppTask()
+{
+    return CustomerAppTask::GetAppTask();
+}
+
+CHIP_ERROR CustomerAppTask::AppInitImpl()
+{
+    SILABS_LOG("CustomerAppTask: custom implementation (AppInitImpl)");
+    CHIP_ERROR err = AppTask::AppInit();
+    if (err == CHIP_NO_ERROR)
+    {
+        // Override the SDK default button handler registered in AppTask::AppInit().
+        chip::DeviceLayer::Silabs::GetPlatform().SetButtonsCb(CustomerAppTask::ButtonEventHandler);
+    }
+    return err;
+}
+
+void CustomerAppTask::ButtonEventHandlerImpl(uint8_t button, uint8_t btnAction)
+{
+    SILABS_LOG("CustomerAppTask: custom implementation (ButtonEventHandlerImpl)");
+    AppEvent aEvent           = {};
+    aEvent.Type               = AppEvent::kEventType_Button;
+    aEvent.ButtonEvent.Action = btnAction;
+
+    if (button == APP_FUNCTION_BUTTON)
+    {
+        aEvent.Handler = BaseApplication::ButtonHandler;
+        AppTask::GetAppTask().PostEvent(&aEvent);
+    }
+}
+```
+
+### Override API Reference
+
+`CHIP_ERROR StartAppTask()` is declared on `AppTask` only. It is not an
+`*Impl()` hook: platform code (for example `MatterConfig`) calls
+`AppTask::GetAppTask().StartAppTask()` with static type `AppTask &`, which runs
+the implementation in `AppTask.cpp` (creating the FreeRTOS app task via
+`BaseApplication::StartAppTask(...)`). To change startup behavior, edit
+`AppTask::StartAppTask()` or `BaseApplication::StartAppTask` in your product
+sources.
+
+The base API and default AppTask behavior for this example are maintained under
+[`include/`](include/AppTaskImpl.h) and [`src/`](src/AppTask.cpp). Use them as
+the reference for overridable methods and app configuration.
+
+| File                                             | Purpose                                                                                                                                              |
+| ------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------- |
+| [`include/AppTaskImpl.h`](include/AppTaskImpl.h) | Declarations of every overridable `*Impl()` method. Copy the signatures you need from here into `CustomerAppTask.h`.                                 |
+| [`src/AppTask.cpp`](src/AppTask.cpp)             | Silicon Labs default implementation of AppTask. This is what runs for any `*Impl()` you do not override. Use as reference when customizing behavior. |
+
 ## Building
 
 -   Download the

examples/air-quality-sensor-app/silabs/include/AirQualityConfig.h

@@ -46,6 +46,10 @@
 // <i> Default: 300
 #define EXTREMELY_POOR_THRESHOLD 300
 
+// <o SENSOR_TIMER_PERIOD_MS> Sensor sampling period in milliseconds
+// <i> Default: 30000 (30 seconds)
+#define SENSOR_TIMER_PERIOD_MS 30000
+
 // <<< end of configuration section >>>
 
 #endif // SL_MATTER_AIR_QUALITY_CONFIG_H

examples/air-quality-sensor-app/silabs/include/AppTask.h

@@ -23,6 +23,7 @@
  * Includes
  *********************************************************/
 
+#include <cstdint>
 #include <stdbool.h>
 #include <stdint.h>
 
@@ -32,9 +33,8 @@
 
 #include "AppEvent.h"
 #include "BaseApplication.h"
-#include "SensorManager.h"
+#include <app/ConcreteAttributePath.h>
 #include <ble/BLEEndPoint.h>
-#include <cmsis_os2.h>
 #include <lib/core/CHIPError.h>
 #include <platform/CHIPDeviceLayer.h>
 
@@ -59,7 +59,7 @@ class AppTask : public BaseApplication
 public:
     AppTask() = default;
 
-    static AppTask & GetAppTask() { return sAppTask; }
+    static AppTask & GetAppTask();
 
     /**
      * @brief AppTask task main loop function
@@ -71,10 +71,15 @@ class AppTask : public BaseApplication
     CHIP_ERROR StartAppTask();
 
     /**
-     * @brief Request an update of the Air Quality Senor LCD UI
+     * @brief Request an update of the Air Quality Sensor LCD UI
      */
     void UpdateAirQualitySensorUI();
 
+    /**
+     * @brief Update the Air Quality cluster attribute
+     */
+    static void WriteAirQualityToAttribute(intptr_t context);
+
     /**
      * @brief Event handler when a button is pressed
      * Function posts an event for button processing
@@ -85,24 +90,25 @@ class AppTask : public BaseApplication
      */
     static void ButtonEventHandler(uint8_t button, uint8_t btnAction);
 
-private:
-    static AppTask sAppTask;
+    void DMPostAttributeChangeCallback(const chip::app::ConcreteAttributePath & attributePath, uint8_t type, uint16_t size,
+                                       uint8_t * value);
 
     /**
-     * @brief Override of BaseApplication::AppInit() virtual method, called by BaseApplication::Init()
+     * @brief Read the current raw air quality sensor value into @p air_quality.
      *
-     * @return CHIP_ERROR
+     * Calls `AirQualitySensor::GetAirQuality` when `USE_AIR_QUALITY_SENSOR` is set,
+     * otherwise steps through a simulated table. On error @p air_quality is left untouched and
+     * the caller skips scheduling a cluster update for that tick.
      */
-    CHIP_ERROR AppInit() override;
+    CHIP_ERROR GetAirQualityValue(int32_t & air_quality);
 
-    /**
-     * @brief PB0 Button event processing function
-     *        Press and hold will trigger a factory reset timer start
-     *        Press and release will restart BLEAdvertising if not commisionned
-     *
-     * @param aEvent button event being processed
-     */
-    static void ButtonHandler(AppEvent * aEvent);
+    // Reads new generated sensor value, stores it, and updates local Air Quality attribute
+    static void SensorTimerEventHandler(void * arg);
+
+protected:
+    /** Override of `BaseApplication::AppInit()`. */
+    CHIP_ERROR AppInit() override;
 
-    static void AirQualitySensorActionEventHandler(AppEvent * aEvent);
+    /** Bring up the air quality sensor app: Matter manager, sensor timer, sensor driver, first reading. */
+    CHIP_ERROR InitAirQualitySensor();
 };

examples/air-quality-sensor-app/silabs/include/AppTaskImpl.h

@@ -0,0 +1,81 @@
+/*
+ *
+ *    Copyright (c) 2020-2024 Project CHIP Authors
+ *    Copyright (c) 2019-2024 Google LLC.
+ *    All rights reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#pragma once
+
+#include "AppTask.h"
+#include "CRTPHelpers.h"
+
+/**
+ * @brief CRTP base for air quality AppTask, exposing override hooks for customizable APIs.
+ *
+ * Each public method dispatches to `Derived::*Impl()`. Overrides are optional: default
+ * `*Impl()` implementations in the private section forward to `AppTask`. Override in
+ * `CustomerAppTask` only for the behaviors you want to customize.
+ *
+ * @tparam Derived The derived class type (CRTP pattern)
+ */
+template <typename Derived>
+class AppTaskImpl : public AppTask
+{
+public:
+    CHIP_ERROR AppInit() override { CRTP_OPTIONAL_DISPATCH(AppTaskImpl, Derived, AppInitImpl); }
+
+    CHIP_ERROR InitAirQualitySensor() { CRTP_OPTIONAL_DISPATCH(AppTaskImpl, Derived, InitAirQualitySensorImpl); }
+
+    CHIP_ERROR GetAirQualityValue(int32_t & air_quality)
+    {
+        CRTP_OPTIONAL_DISPATCH_ARGS(AppTaskImpl, Derived, GetAirQualityValueImpl, air_quality);
+    }
+
+    static void ButtonEventHandler(uint8_t button, uint8_t btnAction)
+    {
+        CRTP_OPTIONAL_STATIC_DISPATCH(AppTaskImpl, Derived, ButtonEventHandlerImpl, button, btnAction);
+    }
+
+    static void SensorTimerEventHandler(void * arg)
+    {
+        CRTP_OPTIONAL_STATIC_DISPATCH(AppTaskImpl, Derived, SensorTimerEventHandlerImpl, arg);
+    }
+
+    void DMPostAttributeChangeCallback(const chip::app::ConcreteAttributePath & attributePath, uint8_t type, uint16_t size,
+                                       uint8_t * value)
+    {
+        CRTP_OPTIONAL_VOID_DISPATCH(AppTaskImpl, Derived, DMPostAttributeChangeCallbackImpl, attributePath, type, size, value);
+    }
+
+private:
+    friend Derived;
+
+    CHIP_ERROR AppInitImpl() { return AppTask::AppInit(); }
+
+    CHIP_ERROR InitAirQualitySensorImpl() { return AppTask::InitAirQualitySensor(); }
+
+    CHIP_ERROR GetAirQualityValueImpl(int32_t & air_quality) { return AppTask::GetAirQualityValue(air_quality); }
+
+    void ButtonEventHandlerImpl(uint8_t button, uint8_t btnAction) { AppTask::ButtonEventHandler(button, btnAction); }
+
+    void SensorTimerEventHandlerImpl(void * arg) { AppTask::SensorTimerEventHandler(arg); }
+
+    void DMPostAttributeChangeCallbackImpl(const chip::app::ConcreteAttributePath & attributePath, uint8_t type, uint16_t size,
+                                           uint8_t * value)
+    {
+        AppTask::DMPostAttributeChangeCallback(attributePath, type, size, value);
+    }
+};

examples/air-quality-sensor-app/silabs/include/CHIPProjectConfig.h

@@ -108,3 +108,6 @@
  *
  */
 #define CHIP_CONFIG_MRP_LOCAL_ACTIVE_RETRY_INTERVAL (2000_ms32)
+
+// Temporary setting to use CustomerAppTask for apps which are not upgraded to new architecture
+#define CHIP_SILABS_APP_USE_CUSTOMER_APP_TASK