frameworks/native: document native types and enums

Change-Id: Id94b610f27b87426abb30e13484cbd16990aa995
diff --git a/include/android/looper.h b/include/android/looper.h
index 74c0383..718f703 100644
--- a/include/android/looper.h
+++ b/include/android/looper.h
@@ -14,6 +14,14 @@
  * limitations under the License.
  */
 
+/**
+ * @addtogroup Looper
+ * @{
+ */
+
+/**
+ * @file looper.h
+ */
 
 #ifndef ANDROID_LOOPER_H
 #define ANDROID_LOOPER_H
@@ -22,6 +30,7 @@
 extern "C" {
 #endif
 
+struct ALooper;
 /**
  * ALooper
  *
@@ -35,7 +44,6 @@
  *
  * A thread can have only one ALooper associated with it.
  */
-struct ALooper;
 typedef struct ALooper ALooper;
 
 /**
@@ -44,13 +52,14 @@
  */
 ALooper* ALooper_forThread();
 
+/** Option for for ALooper_prepare(). */
 enum {
     /**
-     * Option for ALooper_prepare: this looper will accept calls to
-     * ALooper_addFd() that do not have a callback (that is provide NULL
-     * for the callback).  In this case the caller of ALooper_pollOnce()
-     * or ALooper_pollAll() MUST check the return from these functions to
-     * discover when data is available on such fds and process it.
+     * This looper will accept calls to ALooper_addFd() that do not
+     * have a callback (that is provide NULL for the callback).  In
+     * this case the caller of ALooper_pollOnce() or ALooper_pollAll()
+     * MUST check the return from these functions to discover when
+     * data is available on such fds and process it.
      */
     ALOOPER_PREPARE_ALLOW_NON_CALLBACKS = 1<<0
 };
@@ -64,9 +73,9 @@
  */
 ALooper* ALooper_prepare(int opts);
 
+/** Result from ALooper_pollOnce() and ALooper_pollAll(). */
 enum {
     /**
-     * Result from ALooper_pollOnce() and ALooper_pollAll():
      * The poll was awoken using wake() before the timeout expired
      * and no callbacks were executed and no other file descriptors were ready.
      */
@@ -176,10 +185,12 @@
  *
  * Returns ALOOPER_POLL_ERROR if an error occurred.
  *
- * Returns a value >= 0 containing an identifier if its file descriptor has data
- * and it has no callback function (requiring the caller here to handle it).
- * In this (and only this) case outFd, outEvents and outData will contain the poll
- * events and data associated with the fd, otherwise they will be set to NULL.
+ * Returns a value >= 0 containing an identifier (the same identifier
+ * `ident` passed to ALooper_addFd()) if its file descriptor has data
+ * and it has no callback function (requiring the caller here to
+ * handle it).  In this (and only this) case outFd, outEvents and
+ * outData will contain the poll events and data associated with the
+ * fd, otherwise they will be set to NULL.
  *
  * This method does not return until it has finished invoking the appropriate callbacks
  * for all file descriptors that were signalled.
@@ -254,3 +265,5 @@
 #endif
 
 #endif // ANDROID_LOOPER_H
+
+/** @} */