powermgmt: Small cleanups to battery capacity code

- Don't include the 'battery capacity' setting unless the
  target allows changing it.
- Clean up the preprocessor conditionals used to check for
  variable battery capacity support.
- Don't use a variable for battery capacity unless it is
  actually needed.

Change-Id: I3d8a338f107014f2c5098bc0a44ef0cfb4df9356

apps/menus/settings_menu.c

@@ -259,7 +259,7 @@ static int usbcharging_callback(int action,
 MENUITEM_SETTING(usb_charging, &global_settings.usb_charging, usbcharging_callback);
 #endif /* HAVE_USB_CHARGING_ENABLE */
 MAKE_MENU(battery_menu, ID2P(LANG_BATTERY_MENU), 0, Icon_NOICON,
-#if defined(BATTERY_CAPACITY_INC) && BATTERY_CAPACITY_INC > 0
+#if BATTERY_CAPACITY_INC > 0
             &battery_capacity,
 #endif
 #if BATTERY_TYPES_COUNT > 1

apps/plugins/battery_bench.c

@@ -567,7 +567,12 @@ enum plugin_status plugin_start(const void* parameter)
                 ,MODEL_NAME,rb->rbversion);
 
             rb->fdprintf(fd, "# Battery type: %d mAh      Buffer Entries: %d\n",
-                rb->global_settings->battery_capacity, (int)BUF_ELEMENTS);
+#if BATTERY_CAPACITY_INC > 0
+                         rb->global_settings->battery_capacity,
+#else
+                         BATTERY_CAPACITY_DEFAULT,
+#endif
+                         (int)BUF_ELEMENTS);
 
             rb->fdprintf(fd, "# Rockbox has been running for %02d:%02d:%02d\n",
                 HMS((unsigned)start_tick/HZ));

apps/settings.c

@@ -835,7 +835,7 @@ void settings_apply(bool read_disk)
     set_keypress_restarts_sleep_timer(
         global_settings.keypress_restarts_sleeptimer);
 
-#if defined(BATTERY_CAPACITY_INC) && BATTERY_CAPACITY_INC > 0
+#if BATTERY_CAPACITY_INC > 0
     /* only call if it's really exchangable */
     set_battery_capacity(global_settings.battery_capacity);
 #endif

apps/settings.h

@@ -608,10 +608,9 @@ struct user_settings
 
     /* power settings */
     int poweroff;   /* idle power off timer */
-#if BATTERY_CAPACITY_DEFAULT > 0
+#if BATTERY_CAPACITY_INC > 0
     int battery_capacity; /* in mAh */
 #endif
-
 #if BATTERY_TYPES_COUNT > 1
     int battery_type;  /* for units which can take multiple types (Ondio). */
 #endif

apps/settings_list.c

@@ -1036,13 +1036,7 @@ const struct settings_list settings[] = {
                   NULL, NULL, NULL),
 /* use this setting for user code even if there's no exchangable battery
  * support enabled */
-#if BATTERY_CAPACITY_DEFAULT > 0
-/* define min/max/inc for this file if there's only one battery */
-#ifndef BATTERY_CAPACITY_MIN
-#define BATTERY_CAPACITY_MIN BATTERY_CAPACITY_DEFAULT
-#define BATTERY_CAPACITY_MAX BATTERY_CAPACITY_DEFAULT
-#define BATTERY_CAPACITY_INC 0
-#endif
+#if BATTERY_CAPACITY_INC > 0
 #if defined(IPOD_VIDEO) && !defined(SIMULATOR)
     /* its easier to leave this one un-macro()ed for the time being */
     { F_T_INT|F_DEF_ISFUNC|F_INT_SETTING, &global_settings.battery_capacity,