gpiod: first initialized without readme file

Tested on android-studio bumblebee including kotlin base activity, and
c++ base JNI layer api using libgpiod static libraries.

Support platform:
  - arm64-v8
  - armeabi-v7a

Signed-off-by: Wig Cheng <[email protected]>

.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

app/.gitignore

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+/build

app/build.gradle

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+plugins {
+    id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
+}
+
+android {
+    compileSdk 31
+
+    defaultConfig {
+        applicationId "com.example.gpiod"
+        minSdk 28
+        targetSdk 31
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables {
+            useSupportLibrary true
+        }
+
+        externalNativeBuild {
+            cmake {
+                cppFlags ''
+                abiFilters 'armeabi-v7a', 'arm64-v8a'
+            }
+            ndk {
+                // Specifies the ABI configurations of your native
+                // libraries Gradle should build and package with your app.
+                abiFilters 'armeabi-v7a', 'arm64-v8a'
+            }
+        }
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+    buildFeatures {
+        compose true
+    }
+    composeOptions {
+        kotlinCompilerExtensionVersion compose_version
+    }
+    packagingOptions {
+        resources {
+            excludes += '/META-INF/{AL2.0,LGPL2.1}'
+        }
+    }
+    externalNativeBuild {
+        cmake {
+            path file('src/main/cpp/CMakeLists.txt')
+            version '3.18.1'
+        }
+    }
+}
+
+dependencies {
+
+    implementation 'androidx.core:core-ktx:1.7.0'
+    implementation "androidx.compose.ui:ui:$compose_version"
+    implementation "androidx.compose.material:material:$compose_version"
+    implementation "androidx.compose.ui:ui-tooling-preview:$compose_version"
+    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
+    implementation 'androidx.activity:activity-compose:1.3.1'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
+    androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_version"
+    debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"
+}

app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

app/src/androidTest/java/com/example/gpiod/ExampleInstrumentedTest.kt

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+package com.example.gpiod
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.example.gpiod", appContext.packageName)
+    }
+}

app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.gpiod">
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.Gpiod">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:label="@string/app_name"
+            android:theme="@style/Theme.Gpiod">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

app/src/main/cpp/CMakeLists.txt

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+
+# For more information about using CMake with Android Studio, read the
+# documentation: https://d.android.com/studio/projects/add-native-code.html
+
+# Sets the minimum version of CMake required to build the native library.
+
+cmake_minimum_required(VERSION 3.18.1)
+
+# Declares and names the project.
+
+project("JNIGpiod")
+
+# Creates and names a library, sets it as either STATIC
+# or SHARED, and provides the relative paths to its source code.
+# You can define multiple libraries, and CMake builds them for you.
+# Gradle automatically packages shared libraries with your APK.
+
+add_library( # Sets the name of the library.
+             JNIGpiod
+
+             # Sets the library as a shared library.
+             SHARED
+
+             # Provides a relative path to your source file(s).
+             JNIGpiod.cpp )
+
+# Searches for a specified prebuilt library and stores the path as a
+# variable. Because CMake includes system libraries in the search path by
+# default, you only need to specify the name of the public NDK library
+# you want to add. CMake verifies that the library exists before
+# completing its build.
+
+find_library( # Sets the name of the path variable.
+              log-lib
+
+              # Specifies the name of the NDK library that
+              # you want CMake to locate.
+              log )
+
+# Specifies libraries CMake should link to your target library. You
+# can link multiple libraries, such as libraries you define in this
+# build script, prebuilt third-party libraries, or system libraries.
+
+include_directories(${ANDROID_ABI}/)
+add_library(gpiod STATIC IMPORTED)
+set_target_properties(gpiod PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/${ANDROID_ABI}/libgpiod.a)
+
+
+target_link_libraries( # Specifies the target library.
+                       JNIGpiod
+                       gpiod
+                       # Links the target library to the log library
+                       # included in the NDK.
+                       ${log-lib} )

app/src/main/cpp/JNIGpiod.cpp

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+// Write C++ code here.
+//
+// Do not forget to dynamically load the C++ library into your application.
+//
+// For instance,
+//
+// In MainActivity.java:
+//    static {
+//       System.loadLibrary("gpiod");
+//    }
+//
+// Or, in MainActivity.kt:
+//    companion object {
+//      init {
+//         System.loadLibrary("gpiod")
+//      }
+//    }
+
+#define LOG_TAG    "gpiod-lib_JNI"
+#include <cstring>
+#include <jni.h>
+#include <cinttypes>
+#include <string>
+#include <gpiod.h>
+#include <android/log.h>
+
+extern "C"
+JNIEXPORT jint JNICALL
+Java_com_example_gpiod_MainActivity_getGpioTotalBank(JNIEnv *env, jobject thiz) {
+    std::ignore = thiz;
+    struct gpiod_chip_iter *iter;
+    struct gpiod_chip *chip;
+    unsigned int total_bank = 0;
+
+    iter = gpiod_chip_iter_new();
+    gpiod_foreach_chip(iter, chip) {
+        total_bank += 1;
+    }
+
+    gpiod_chip_iter_free(iter);
+
+    return total_bank;
+}
+
+extern "C"
+JNIEXPORT jstring JNICALL
+Java_com_example_gpiod_MainActivity_getGpioInfo(JNIEnv *env, jobject thiz, jint gpiobank, jint gpioline) {
+    std::ignore = thiz;
+
+    char bank[32] = {0}, ret[4] = {0};
+    sprintf(bank, "gpiochip%d", gpiobank);
+    __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "GPIO gpiobank is %d", gpiobank);
+    __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "GPIO gpioline is %d", gpioline);
+
+    jint value = gpiod_ctxless_get_value((char *)bank, gpioline, 0, "gpioget");
+
+    sprintf(ret, "%d", value);
+
+    return env->NewStringUTF(ret);
+}
+
+extern "C"
+JNIEXPORT jstring JNICALL
+Java_com_example_gpiod_MainActivity_setGpioInfo(JNIEnv *env, jobject thiz, jint gpiobank, jint gpioline, jint gpio_value) {
+
+    std::ignore = thiz;
+
+    char bank[32] = {0}, ret_str[32] = {0};
+    sprintf(bank, "/dev/gpiochip%d", gpiobank);
+
+    int ret = gpiod_ctxless_set_value(bank, gpioline, gpio_value, 0, "gpioset", NULL, NULL);
+
+    if(ret)
+        sprintf(ret_str, "Set Failed !");
+    else
+        sprintf(ret_str, "Set Successed !");
+
+    __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "set gpio ret = %d", ret);
+    return env->NewStringUTF(ret_str);
+}
+
+
+extern "C"
+JNIEXPORT jstring JNICALL
+Java_com_example_gpiod_MainActivity_stringFromJNI(JNIEnv *env, jobject thiz) {
+    // TODO: implement stringFromJNI()
+    return env->NewStringUTF("Test");
+}