Add support for more boards e.g. iMX7d

Add more board variants to support their respective namings of GPIO pins
for input button

Bug: 63540960

Change-Id: Iaa1c4a03f55e74c6d95cc2334bdb1237671f8e08

app/src/main/java/com/example/androidthings/doorbell/BoardDefaults.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2016, The Android Open Source Project
+ *
+ * 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.
+ */
+
+package com.example.androidthings.doorbell;
+
+import android.os.Build;
+
+import com.google.android.things.pio.PeripheralManagerService;
+
+import java.util.List;
+
+@SuppressWarnings("WeakerAccess")
+public class BoardDefaults {
+    private static final String DEVICE_EDISON_ARDUINO = "edison_arduino";
+    private static final String DEVICE_EDISON = "edison";
+    private static final String DEVICE_JOULE = "joule";
+    private static final String DEVICE_RPI3 = "rpi3";
+    private static final String DEVICE_IMX6UL_PICO = "imx6ul_pico";
+    private static final String DEVICE_IMX6UL_VVDN = "imx6ul_iopb";
+    private static final String DEVICE_IMX7D_PICO = "imx7d_pico";
+    private static String sBoardVariant = "";
+
+    /**
+     * Return the GPIO pin that the Button is connected on.
+     */
+    public static String getGPIOForButton() {
+        switch (getBoardVariant()) {
+            case DEVICE_RPI3:
+                return "BCM21";
+            case DEVICE_IMX7D_PICO:
+                return "GPIO_174";
+            default:
+                throw new IllegalStateException("Unknown Build.DEVICE " + Build.DEVICE);
+        }
+    }
+
+    private static String getBoardVariant() {
+        if (!sBoardVariant.isEmpty()) {
+            return sBoardVariant;
+        }
+        sBoardVariant = Build.DEVICE;
+        // For the edison check the pin prefix
+        // to always return Edison Breakout pin name when applicable.
+        if (sBoardVariant.equals(DEVICE_EDISON)) {
+            PeripheralManagerService pioService = new PeripheralManagerService();
+            List<String> gpioList = pioService.getGpioList();
+            if (gpioList.size() != 0) {
+                String pin = gpioList.get(0);
+                if (pin.startsWith("IO")) {
+                    sBoardVariant = DEVICE_EDISON_ARDUINO;
+                }
+            }
+        }
+        return sBoardVariant;
+    }
+}

app/src/main/java/com/example/androidthings/doorbell/DoorbellActivity.java

@@ -51,7 +51,7 @@ public class DoorbellActivity extends Activity {
     /*
      * Driver for the doorbell button;
      */
-    private ButtonInputDriver mButton;
+    private ButtonInputDriver mButtonInputDriver;
 
     /**
      * A {@link Handler} for running Camera tasks in the background.
@@ -73,12 +73,6 @@ public class DoorbellActivity extends Activity {
      */
     private HandlerThread mCloudThread;
 
-    /**
-     * The GPIO pin to activate to listen for button presses.
-     */
-    private final String BUTTON_GPIO_PIN = "BCM21";
-
-
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -104,17 +98,26 @@ public void onCreate(Bundle savedInstanceState) {
         mCloudHandler = new Handler(mCloudThread.getLooper());
 
         // Initialize the doorbell button driver
-        try {
-            mButton = new ButtonInputDriver(BUTTON_GPIO_PIN,
-                Button.LogicState.PRESSED_WHEN_LOW, KeyEvent.KEYCODE_ENTER);
-        } catch (IOException e) {
-            Log.e(TAG, "button driver error", e);
-        }
+        initPIO();
+
         // Camera code is complicated, so we've shoved it all in this closet class for you.
         mCamera = DoorbellCamera.getInstance();
         mCamera.initializeCamera(this, mCameraHandler, mOnImageAvailableListener);
     }
 
+    private void initPIO() {
+        try {
+            mButtonInputDriver = new ButtonInputDriver(
+                    BoardDefaults.getGPIOForButton(),
+                    Button.LogicState.PRESSED_WHEN_LOW,
+                    KeyEvent.KEYCODE_ENTER);
+            mButtonInputDriver.register();
+        } catch (IOException e) {
+            mButtonInputDriver = null;
+            Log.w(TAG, "Could not open GPIO pins", e);
+        }
+    }
+
     @Override
     protected void onDestroy() {
         super.onDestroy();
@@ -123,7 +126,7 @@ protected void onDestroy() {
         mCameraThread.quitSafely();
         mCloudThread.quitSafely();
         try {
-            mButton.close();
+            mButtonInputDriver.close();
         } catch (IOException e) {
             Log.e(TAG, "button driver error", e);
         }