Rework powermgmt to enable code re-use on appliation and sims.

* Introduce CONFIG_BATTERY_MEASURE define, to allow targets (application)
to break powermgmt.c's assumption about the ability to read battery voltage.
There's now additionally percentage (android) and remaining time measure
(maemo). No measure at all also works (sdl app). If voltage can't be measured,
then battery_level() is king and it'll be used for power_history and runtime
estimation.

* Implement target's API in the simulator, i.e. _battery_voltage(), so it
doesn't need to implement it's own powermgmt.c and other stubs. Now
the sim behaves much more like a native target, although it still
changes the simulated battery voltage quickly,

* Other changes include include renaming battery_adc_voltage() to
_battery_voltage(), for consistency with the new target functions and
making some of the apps code aware that voltage and runtime estimation
is not always available.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31548 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 7 insertions, 3 deletions

diff --git a/apps/gui/skin_engine/skin_tokens.c b/apps/gui/skin_engine/skin_tokens.c
index 169c4a36fd..bae8ae8f8e 100644
--- a/apps/gui/skin_engine/skin_tokens.c
+++ b/apps/gui/skin_engine/skin_tokens.c
@@ -1068,9 +1068,13 @@ const char *get_token_value(struct gui_wps *gwps,
 
         case SKIN_TOKEN_BATTERY_VOLTS:
         {
-            unsigned int v = battery_voltage();
-            snprintf(buf, buf_size, "%d.%02d", v / 1000, (v % 1000) / 10);
-            return buf;
+            int v = battery_voltage();
+            if (v >= 0) {
+                snprintf(buf, buf_size, "%d.%02d", v / 1000, (v % 1000) / 10);
+                return buf;
+            } else {
+                return "?";
+            }
         }
 
         case SKIN_TOKEN_BATTERY_TIME: