charger-manager: Poll battery health in normal state

Charger-Manager needs to check battery health in normal state
as well as suspend-to-RAM state. When the battery is fully charged,
Charger-Manager needs to determine when the chargers restart charging.

This patch allows Charger-Manager to monitor battery health in normal
state and handle operation for chargers after battery is fully charged.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

Documentation/power/charger-manager.txt

@@ -44,6 +44,12 @@ Charger Manager supports the following:
 	Normally, the platform will need to resume and suspend some devices
 	that are used by Charger Manager.
 
+* Support for premature full-battery event handling
+	If the battery voltage drops by "fullbatt_vchkdrop_uV" after
+	"fullbatt_vchkdrop_ms" from the full-battery event, the framework
+	restarts charging. This check is also performed while suspended by
+	setting wakeup time accordingly and using suspend_again.
+
 2. Global Charger-Manager Data related with suspend_again
 ========================================================
 In order to setup Charger Manager with suspend-again feature
@@ -55,7 +61,7 @@ if there are multiple batteries. If there are multiple batteries, the
 multiple instances of Charger Manager share the same charger_global_desc
 and it will manage in-suspend monitoring for all instances of Charger Manager.
 
-The user needs to provide all the two entries properly in order to activate
+The user needs to provide all the three entries properly in order to activate
 in-suspend monitoring:
 
 struct charger_global_desc {
@@ -74,6 +80,11 @@ bool (*rtc_only_wakeup)(void);
 	same struct. If there is any other wakeup source triggered the
 	wakeup, it should return false. If the "rtc" is the only wakeup
 	reason, it should return true.
+
+bool assume_timer_stops_in_suspend;
+	: if true, Charger Manager assumes that
+	the timer (CM uses jiffies as timer) stops during suspend. Then, CM
+	assumes that the suspend-duration is same as the alarm length.
 };
 
 3. How to setup suspend_again
@@ -111,6 +122,16 @@ enum polling_modes polling_mode;
 	  CM_POLL_CHARGING_ONLY: poll this battery if and only if the
 				 battery is being charged.
 
+unsigned int fullbatt_vchkdrop_ms;
+unsigned int fullbatt_vchkdrop_uV;
+	: If both have non-zero values, Charger Manager will check the
+	battery voltage drop fullbatt_vchkdrop_ms after the battery is fully
+	charged. If the voltage drop is over fullbatt_vchkdrop_uV, Charger
+	Manager will try to recharge the battery by disabling and enabling
+	chargers. Recharge with voltage drop condition only (without delay
+	condition) is needed to be implemented with hardware interrupts from
+	fuel gauges or charger devices/chips.
+
 unsigned int fullbatt_uV;
 	: If specified with a non-zero value, Charger Manager assumes
 	that the battery is full (capacity = 100) if the battery is not being
@@ -122,6 +143,8 @@ unsigned int polling_interval_ms;
 	this battery every polling_interval_ms or more frequently.
 
 enum data_source battery_present;
+	: CM_BATTERY_PRESENT: assume that the battery exists.
+	CM_NO_BATTERY: assume that the battery does not exists.
 	CM_FUEL_GAUGE: get battery presence information from fuel gauge.
 	CM_CHARGER_STAT: get battery presence from chargers.