ds2760_battery: Fix integer overflow for time_to_empty_now
Daniel Mack [Fri, 24 Jul 2009 13:08:11 +0000 (15:08 +0200)]
On the device we're currently developing, battery sizes of ~2.8Ah and
current flow of ~600mA are typical.

With that values, the life_sec computation overflows due to the
multiplication by 3600.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
Cc: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>

drivers/power/ds2760_battery.c

index 1bb8498..6f1dba5 100644 (file)
@@ -211,9 +211,9 @@ static int ds2760_battery_read_status(struct ds2760_device_info *di)
        if (di->rem_capacity > 100)
                di->rem_capacity = 100;
 
-       if (di->current_uA)
-               di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
-                                3600L) / di->current_uA;
+       if (di->current_uA >= 100L)
+               di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L)
+                                       / (di->current_uA / 100L);
        else
                di->life_sec = 0;