pipa: Add Xiaomi Pen support to Xiaomi Peripheral Manager

Change-Id: I2698b754dd062d581f059456670639c71658f3fc

peripheralmanager/Android.bp

@@ -14,4 +14,14 @@ android_app {
     static_libs: [
         "androidx.core_core",
     ],
+    required: [
+        "xiaomi-pen"
+    ],
+}
+
+cc_binary {
+    name: "xiaomi-pen",
+    srcs: [
+        "xiaomi-pen.cpp",
+    ],
 }

peripheralmanager/src/org/lineageos/xiaomiperipheralmanager/BootCompletedReceiver.java

@@ -20,5 +20,6 @@ public class BootCompletedReceiver extends BroadcastReceiver {
     public void onReceive(final Context context, Intent intent) {
         if (DEBUG) Log.d(TAG, "Received boot completed intent");
         KeyboardUtils.setup(context);
+        PenUtils.setup(context);
     }
 }

peripheralmanager/src/org/lineageos/xiaomiperipheralmanager/PenUtils.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2023 The LineageOS Project
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.lineageos.xiaomiperipheralmanager;
+
+import android.content.Context;
+import android.hardware.input.InputManager;
+import android.hardware.input.InputManager.InputDeviceListener;
+import android.os.SystemProperties;
+import android.util.Log;
+import android.view.InputDevice;
+
+public class PenUtils {
+
+    private static final String TAG = "XiaomiPeripheralManagerPenUtils";
+    private static final boolean DEBUG = false;
+
+    private static final int penVendorId = 6421;
+    private static final int penProductId = 19841;
+
+    private static InputManager mInputManager;
+
+    public static void setup(Context context) {
+        mInputManager = (InputManager) context.getSystemService(Context.INPUT_SERVICE);
+        refreshPenMode();
+        mInputManager.registerInputDeviceListener(mInputDeviceListener, null);
+    }
+
+    private static void enablePenMode() {
+        Log.d(TAG, "enablePenMode: Enable Pen Mode");
+        SystemProperties.set("persist.sys.parts.pen", "18");
+    }
+
+    private static void disablePenMode() {
+        Log.d(TAG, "disablePenMode: Disable Pen Mode");
+        SystemProperties.set("persist.sys.parts.pen", "0");
+    }
+
+    private static void refreshPenMode() {
+        for (int id : mInputManager.getInputDeviceIds()) {
+            if (isDeviceXiaomiPen(id)) {
+                if (DEBUG) Log.d(TAG, "refreshPenMode: Found Xiaomi Pen");
+                enablePenMode();
+                return;
+            }
+        }
+        if (DEBUG) Log.d(TAG, "refreshPenMode: No Xiaomi Pen found");
+        disablePenMode();
+    }
+
+    private static boolean isDeviceXiaomiPen(int id) {
+        InputDevice inputDevice = mInputManager.getInputDevice(id);
+        return inputDevice.getVendorId() == penVendorId &&
+                inputDevice.getProductId() == penProductId;
+    }
+
+    private static InputDeviceListener mInputDeviceListener = new InputDeviceListener() {
+            @Override
+            public void onInputDeviceAdded(int id) {
+                refreshPenMode();
+            }
+            @Override
+            public void onInputDeviceRemoved(int id) {
+                refreshPenMode();
+            }
+            @Override
+            public void onInputDeviceChanged(int id) {
+                refreshPenMode();
+            }
+        };
+}

peripheralmanager/xiaomi-pen.cpp

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2023 The LineageOS Project
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <iostream>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+
+#define SET_CUR_VALUE 0
+#define TOUCH_PEN_MODE 20
+#define TOUCH_MAGIC 't'
+#define TOUCH_IOC_SETMODE _IO(TOUCH_MAGIC, SET_CUR_VALUE)
+#define TOUCH_DEV_PATH "/dev/xiaomi-touch"
+#define TOUCH_ID 0
+
+int main(int argc, char **argv) {
+    if(argc != 2) {
+        fprintf(stderr, "Usage: %s <value>\n", argv[0]);
+        return -1;
+    }
+    int fd = open(TOUCH_DEV_PATH, O_RDWR);
+    int arg[3] = {TOUCH_ID, TOUCH_PEN_MODE, atoi(argv[1])};
+    ioctl(fd, TOUCH_IOC_SETMODE, &arg);
+    close(fd);
+}

rootdir/etc/init.device.rc

@@ -7,3 +7,6 @@
 on boot
     # WiFi country code
     setprop ro.boot.wificountrycode US
+
+on property:persist.sys.parts.pen=*
+    exec /system/bin/xiaomi-pen ${persist.sys.parts.pen}