[PATCH v2] charger_manager: update charge profile upon temperature zone change

[Ramakrishna Pallala <ramakrishna.pallala@intel.com>]

Battery vendors like UER suggest to program Low Charge Voltage in case
of high or low temperatures. So a battery can have different charge profile
with in the battery operating temperature limits.

Next, there could be events like drop or rise in VBUS voltage in that case
we might have to adjust the charge current to stabilize VBUS voltage.

This patch allows the Charger-Manager to adjust the charging parameters
upon events like VBUS rise or drop and allows batteries to have multiple
charge profiles for different temperature zones.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
---
 Documentation/power/charger-manager.txt |   10 ++++++++++
 drivers/power/charger-manager.c         |    6 +++++-
 include/linux/power/charger-manager.h   |    5 +++++
 3 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/Documentation/power/charger-manager.txt b/Documentation/power/charger-manager.txt
index b4f7f4b..6fa2a10 100644
--- a/Documentation/power/charger-manager.txt
+++ b/Documentation/power/charger-manager.txt
@@ -50,6 +50,15 @@ Charger Manager supports the following:
 	restarts charging. This check is also performed while suspended by
 	setting wakeup time accordingly and using suspend_again.
 
+* Support for adjusting charging parameters
+	Batteries can have different charge profiles with in the battery
+	operating temperature limits. And events like drop or rise in VBUS
+	voltage require adjustment of charge current to stabilize VBUS voltage.
+
+	Charger Manager provides a function pointer "charging_zone_changed" which
+	can be implemented by platform/core drivers and Charger Manager checks
+	this function to update the charger.
+
 * Support for uevent-notify
 	With the charger-related events, the device sends
 	notification to users with UEVENT.
@@ -169,6 +178,7 @@ char *psy_fuel_gauge;
 	: Power-supply-class name of the fuel gauge.
 
 int (*temperature_out_of_range)(int *mC);
+bool (*charging_zone_changed)(int mC);
 bool measure_battery_temp;
 	: This callback returns 0 if the temperature is safe for charging,
 	a positive number if it is too hot to charge, and a negative number
diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
index 86935ec..9f46353 100644
--- a/drivers/power/charger-manager.c
+++ b/drivers/power/charger-manager.c
@@ -424,13 +424,17 @@ static void fullbatt_vchk(struct work_struct *work)
 static bool _cm_monitor(struct charger_manager *cm)
 {
 	struct charger_desc *desc = cm->desc;
+	bool update_charger = false;
 	int temp = desc->temperature_out_of_range(&cm->last_temp_mC);
 
 	dev_dbg(cm->dev, "monitoring (%2.2d.%3.3dC)\n",
 		cm->last_temp_mC / 1000, cm->last_temp_mC % 1000);
 
+	if (desc->charging_zone_changed)
+		update_charger = desc->charging_zone_changed(cm->last_temp_mC);
+
 	/* It has been stopped or charging already */
-	if (!!temp == !!cm->emergency_stop)
+	if ((!!temp == !!cm->emergency_stop) && !update_charger)
 		return false;
 
 	if (temp) {
diff --git a/include/linux/power/charger-manager.h b/include/linux/power/charger-manager.h
index 241065c..302107d 100644
--- a/include/linux/power/charger-manager.h
+++ b/include/linux/power/charger-manager.h
@@ -90,6 +90,10 @@ struct charger_global_desc {
  *	return_value > 0: overheat
  *	return_value == 0: normal
  *	return_value < 0: cold
+ * @charging_zone_changed:
+ *	Determine whether charge profile need an update
+ *	return_value true if charge profile update required
+ *	return_value false if charge profile update is not required
  * @measure_battery_temp:
  *	true: measure battery temperature
  *	false: measure ambient temperature
@@ -114,6 +118,7 @@ struct charger_desc {
 	char *psy_fuel_gauge;
 
 	int (*temperature_out_of_range)(int *mC);
+	bool (*charging_zone_changed)(int mC);
 	bool measure_battery_temp;
 };
 
-- 
1.7.0.4