Log battery and charger states in human readable format

Add helpers for getting state names and use them in diagnostic logging.

datapipe.c

@@ -1019,6 +1019,46 @@ const char *usb_cable_state_repr(usb_cable_state_t state)
 	return res;
 }
 
+/** Convert charger_state_t enum to human readable string
+ *
+ * @param state charger_state_t enumeration value
+ *
+ * @return human readable representation of state
+ */
+const char *charger_state_repr(charger_state_t state)
+{
+	const char *res = "unknown";
+
+	switch( state ) {
+	case CHARGER_STATE_UNDEF: res = "undefined"; break;
+	case CHARGER_STATE_OFF:   res = "off";       break;
+	case CHARGER_STATE_ON:    res = "on";        break;
+	default: break;
+	}
+
+	return res;
+}
+
+/** Convert battery_status_t enum to human readable string
+ *
+ * @param state battery_status_t enumeration value
+ *
+ * @return human readable representation of state
+ */
+const char *battery_status_repr(battery_status_t state)
+{
+	const char *res = "unknown";
+	switch( state ) {
+	case BATTERY_STATUS_UNDEF: res = "undefined"; break;
+	case BATTERY_STATUS_FULL:  res = "full";      break;
+	case BATTERY_STATUS_OK:    res = "ok";        break;
+	case BATTERY_STATUS_LOW:   res = "low";       break;
+	case BATTERY_STATUS_EMPTY: res = "empty";     break;
+	default: break;
+	}
+	return res;
+}
+
 void datapipe_handlers_install(datapipe_handler_t *bindings)
 {
     if( !bindings )

mce.h

@@ -241,13 +241,17 @@ typedef enum {
 	BATTERY_STATUS_EMPTY = 3,	/**< Battery empty */
 } battery_status_t;
 
+const char *battery_status_repr(battery_status_t state);
+
 /** Charging status */
 typedef enum {
 	CHARGER_STATE_UNDEF = -1,	/**< Not known yet */
 	CHARGER_STATE_OFF   =  0,	/**< Not charging */
 	CHARGER_STATE_ON    =  1,	/**< Charging */
 } charger_state_t;
 
+const char *charger_state_repr(charger_state_t state);
+
 /** Camera button state */
 typedef enum {
 	CAMERA_BUTTON_UNDEF = -1,	/**< Camera button state not set */

modules/battery-upower.c

@@ -691,7 +691,9 @@ mcebat_update_cb(gpointer user_data)
 
     /* Process changes */
     if( mcebat.charger != prev.charger ) {
-        mce_log(LL_INFO, "charger: %d -> %d", prev.charger, mcebat.charger);
+        mce_log(LL_INFO, "charger: %s -> %s",
+                charger_state_repr(prev.charger),
+                charger_state_repr(mcebat.charger));
 
         /* Charger connected state */
         execute_datapipe(&charger_state_pipe, GINT_TO_POINTER(mcebat.charger),

tklock.c

@@ -973,7 +973,9 @@ static void tklock_datapipe_charger_state_cb(gconstpointer data)
     if( charger_state == prev )
         goto EXIT;
 
-    mce_log(LL_DEBUG, "charger_state = %d -> %d", prev, charger_state);
+    mce_log(LL_DEBUG, "charger_state = %s -> %s",
+            charger_state_repr(prev),
+            charger_state_repr(charger_state));
 
     /* No exception on mce startup */
     if( prev == CHARGER_STATE_UNDEF )
@@ -1001,7 +1003,9 @@ static void tklock_datapipe_battery_status_cb(gconstpointer data)
     if( battery_status == prev )
         goto EXIT;
 
-    mce_log(LL_DEBUG, "battery_status = %d -> %d", prev, battery_status);
+    mce_log(LL_DEBUG, "battery_status = %s -> %s",
+            battery_status_repr(prev),
+            battery_status_repr(battery_status));
 
 #if 0 /* At the moment there is no notification associated with
        * battery full -> no need to turn the display on */