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.
 

include/linux/power/charger-manager.h

@@ -18,6 +18,8 @@
 #include <linux/power_supply.h>
 
 enum data_source {
+	CM_BATTERY_PRESENT,
+	CM_NO_BATTERY,
 	CM_FUEL_GAUGE,
 	CM_CHARGER_STAT,
 };
@@ -38,11 +40,18 @@ enum polling_modes {
  *	rtc_only_wakeup() returning false.
  *	If the RTC given to CM is the only wakeup reason,
  *	rtc_only_wakeup should return true.
+ * @assume_timer_stops_in_suspend:
+ *	Assume that the jiffy timer stops in suspend-to-RAM.
+ *	When enabled, CM does not rely on jiffies value in
+ *	suspend_again and assumes that jiffies value does not
+ *	change during suspend.
  */
 struct charger_global_desc {
 	char *rtc_name;
 
 	bool (*rtc_only_wakeup)(void);
+
+	bool assume_timer_stops_in_suspend;
 };
 
 /**
@@ -50,6 +59,11 @@ struct charger_global_desc {
  * @psy_name: the name of power-supply-class for charger manager
  * @polling_mode:
  *	Determine which polling mode will be used
+ * @fullbatt_vchkdrop_ms:
+ * @fullbatt_vchkdrop_uV:
+ *	Check voltage drop after the battery is fully charged.
+ *	If it has dropped more than fullbatt_vchkdrop_uV after
+ *	fullbatt_vchkdrop_ms, CM will restart charging.
  * @fullbatt_uV: voltage in microvolt
  *	If it is not being charged and VBATT >= fullbatt_uV,
  *	it is assumed to be full.
@@ -76,6 +90,8 @@ struct charger_desc {
 	enum polling_modes polling_mode;
 	unsigned int polling_interval_ms;
 
+	unsigned int fullbatt_vchkdrop_ms;
+	unsigned int fullbatt_vchkdrop_uV;
 	unsigned int fullbatt_uV;
 
 	enum data_source battery_present;
@@ -101,6 +117,11 @@ struct charger_desc {
  * @fuel_gauge: power_supply for fuel gauge
  * @charger_stat: array of power_supply for chargers
  * @charger_enabled: the state of charger
+ * @fullbatt_vchk_jiffies_at:
+ *	jiffies at the time full battery check will occur.
+ * @fullbatt_vchk_uV: voltage in microvolt
+ *	criteria for full battery
+ * @fullbatt_vchk_work: work queue for full battery check
  * @emergency_stop:
  *	When setting true, stop charging
  * @last_temp_mC: the measured temperature in milli-Celsius
@@ -121,6 +142,10 @@ struct charger_manager {
 
 	bool charger_enabled;
 
+	unsigned long fullbatt_vchk_jiffies_at;
+	unsigned int fullbatt_vchk_uV;
+	struct delayed_work fullbatt_vchk_work;
+
 	int emergency_stop;
 	int last_temp_mC;