Add Onyx Nova 2 frontlight controller (#248)

based on writing to sysfs nodes.
On onyx nova 2 these are: /sys/class/backlight/{warm,white}/brightness

app/src/org/koreader/launcher/device/DeviceInfo.kt

@@ -36,6 +36,7 @@ object DeviceInfo {
     private val CREMA: Boolean
     private val CREMA_0650L: Boolean
     private val ONYX_C67: Boolean
+    private val ONYX_NOVA2: Boolean
     private val ENERGY: Boolean
     private val INKBOOK: Boolean
     private val TOLINO: Boolean
@@ -72,7 +73,8 @@ object DeviceInfo {
 
     enum class LightsDevice {
         NONE,
-        TOLINO_EPOS
+        TOLINO_EPOS,
+        ONYX_NOVA2
     }
 
     enum class BugDevice {
@@ -142,6 +144,12 @@ object DeviceInfo {
         CREMA_0650L = BRAND.contentEquals("crema") && PRODUCT.contentEquals("keplerb")
         deviceMap[EinkDevice.CREMA_0650L] = CREMA_0650L
 
+        // Onyx NOVA 2
+        ONYX_NOVA2 = (MANUFACTURER.contentEquals("onyx")
+                && PRODUCT.contentEquals("nova2")
+                && DEVICE.contentEquals("nova2"))
+        lightsMap[LightsDevice.ONYX_NOVA2] = ONYX_NOVA2
+
         // Onyx C67
         ONYX_C67 = (MANUFACTURER.contentEquals("onyx")
                 && (PRODUCT.startsWith("c67") || MODEL.contentEquals("rk30sdk"))

app/src/org/koreader/launcher/device/LightsFactory.kt

@@ -5,6 +5,7 @@ import java.util.Locale
 
 import org.koreader.launcher.device.lights.GenericController
 import org.koreader.launcher.device.lights.TolinoWarmthController
+import org.koreader.launcher.device.lights.OnyxWarmthController
 import org.koreader.launcher.utils.Logger
 
 object LightsFactory {
@@ -15,6 +16,10 @@ object LightsFactory {
                     logController("Tolino")
                     TolinoWarmthController()
                 }
+                DeviceInfo.LightsDevice.ONYX_NOVA2 -> {
+                    logController("ONYX_NOVA2")
+                    OnyxWarmthController()
+                }
                 else -> {
                     logController("Generic")
                     GenericController()

app/src/org/koreader/launcher/device/lights/OnyxWarmthController.kt

@@ -0,0 +1,106 @@
+package org.koreader.launcher.device.lights
+
+import java.io.File
+
+import android.app.Activity
+import android.util.Log
+
+import org.koreader.launcher.interfaces.LightInterface
+import org.koreader.launcher.utils.Logger
+
+class OnyxWarmthController : LightInterface {
+    companion object {
+        private const val TAG = "lights"
+        private const val BRIGHTNESS_MAX = 255
+        private const val WARMTH_MAX = 255
+        private const val MIN = 0
+        private const val WHITE_FILE = "/sys/class/backlight/white/brightness"
+        private const val WARMTH_FILE = "/sys/class/backlight/warm/brightness"
+    }
+
+    override fun hasFallback(): Boolean {
+        return false
+    }
+
+    override fun hasWarmth(): Boolean {
+        return true
+    }
+
+    override fun needsPermission(): Boolean {
+        return false
+    }
+
+    override fun getBrightness(activity: Activity): Int {
+        val brightnessFile = File(WHITE_FILE)
+        return try {
+            // .replace("\n", "") is needed, since it's automatically appended
+            // without it exception is thrown
+            // java.lang.NumberFormatException: For input string: "125\n"
+            return brightnessFile.readText().replace("\n", "").toInt()
+        } catch (e: Exception) {
+            Logger.w(TAG, Log.getStackTraceString(e))
+            0
+        }
+    }
+
+    override fun getWarmth(activity: Activity): Int {
+        val warmthFile = File(WARMTH_FILE)
+        return try {
+            // .replace("\n", "") is needed, since it's automatically appended
+            // without it exception is thrown
+            // java.lang.NumberFormatException: For input string: "125\n"
+            return warmthFile.readText().replace("\n", "").toInt()
+        } catch (e: Exception) {
+            Logger.w(TAG, Log.getStackTraceString(e))
+            0
+        }
+    }
+
+    override fun setBrightness(activity: Activity, brightness: Int) {
+        if (brightness < MIN || brightness > BRIGHTNESS_MAX) {
+            Logger.w(TAG, "brightness value of of range: $brightness")
+            return
+        }
+        Logger.v(TAG, "Setting brightness to $brightness")
+        val brightnessFile = File(WHITE_FILE)
+        try {
+            brightnessFile.writeText(brightness.toString())
+        } catch (e: Exception) {
+            Logger.w(TAG, "$e")
+        }
+    }
+
+    override fun setWarmth(activity: Activity, warmth: Int) {
+        if (warmth < MIN || warmth > WARMTH_MAX) {
+            Logger.w(TAG, "warmth value of of range: $warmth")
+            return
+        }
+        val warmthFile = File(WARMTH_FILE)
+        Logger.v(TAG, "Setting warmth to $warmth")
+        try {
+            warmthFile.writeText(warmth.toString())
+        } catch (e: Exception) {
+            Logger.w(TAG, "$e")
+        }
+    }
+
+    override fun getMinWarmth(): Int {
+        return MIN
+    }
+
+    override fun getMaxWarmth(): Int {
+        return WARMTH_MAX
+    }
+
+    override fun getMinBrightness(): Int {
+        return MIN
+    }
+
+    override fun getMaxBrightness(): Int {
+        return BRIGHTNESS_MAX
+    }
+
+    override fun enableFrontlightSwitch(activity: Activity): Int {
+        return 1
+    }
+}