power: ab8500_bm: Low battery IRQ is now handled correctly

This patch fixes the problem with reporting 0% capacity once the low
battery IRQ has been triggered. We will allow single dips in
battery voltage without reporting 0% capacity

ST-Ericsson ID: ER320113
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: I6e6a25c36c697c7401ac89a2c8569690d672c3b6
Signed-off-by: Johan Palsson <johan.palsson@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/13035
Reviewed-by: QATOOLS
Reviewed-by: Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com>

1 files changed, 55 insertions, 9 deletions

diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c
index 542f304005b..8fcd08d4aee 100644
--- a/drivers/power/ab8500_fg.c
+++ b/drivers/power/ab8500_fg.c
@@ -35,6 +35,8 @@
 
 #define NBR_AVG_SAMPLES			20
 
+#define LOW_BAT_CHECK_INTERVAL		(2 * HZ)
+
 #define interpolate(x, x1, y1, x2, y2) \
 	((y1) + ((((y2) - (y1)) * ((x) - (x1))) / ((x2) - (x1))));
 
@@ -101,6 +103,7 @@ struct ab8500_fg_flags {
 	bool conv_done;
 	bool charging;
 	bool fully_charged;
+	bool low_bat_delay;
 	bool low_bat;
 	bool bat_ovv;
 };
@@ -130,6 +133,7 @@ struct ab8500_fg_flags {
  * @fg_psy:		Structure that holds the FG specific battery properties
  * @fg_wq:		Work queue for running the FG algorithm
  * @fg_periodic_work:	Work to run the FG algorithm periodically
+ * @fg_low_bat_work:	Work to check low bat condition
  * @fg_work:		Work to run the FG algorithm instantly
  * @fg_acc_cur_work:	Work to read the FG accumulator
  * @cc_lock:		Mutex for locking the CC
@@ -158,6 +162,7 @@ struct ab8500_fg {
 	struct power_supply fg_psy;
 	struct workqueue_struct *fg_wq;
 	struct delayed_work fg_periodic_work;
+	struct delayed_work fg_low_bat_work;
 	struct work_struct fg_work;
 	struct work_struct fg_acc_cur_work;
 	struct mutex cc_lock;
@@ -877,6 +882,7 @@ static void ab8500_fg_check_capacity_limits(struct ab8500_fg *di, bool init)
 				di->bat_cap.permille);
 			di->bat_cap.prev_percent = di->bat_cap.permille / 10;
 			di->bat_cap.prev_mah = di->bat_cap.mah;
+
 			changed = true;
 		} else {
 			dev_dbg(di->dev, "capacity not allowed to go up since "
@@ -1178,6 +1184,44 @@ static void ab8500_fg_periodic_work(struct work_struct *work)
 }
 
 /**
+ * ab8500_fg_low_bat_work() - Check LOW_BAT condition
+ * @work:	pointer to the work_struct structure
+ *
+ * Work queue function for checking the LOW_BAT condition
+ */
+static void ab8500_fg_low_bat_work(struct work_struct *work)
+{
+	int vbat;
+
+	struct ab8500_fg *di = container_of(work, struct ab8500_fg,
+		fg_low_bat_work.work);
+
+	vbat = ab8500_fg_bat_voltage(di);
+
+	/* Check if LOW_BAT still fulfilled */
+	if (vbat < di->bat->fg_params->lowbat_threshold) {
+		di->flags.low_bat = true;
+		dev_warn(di->dev, "Battery voltage still LOW\n");
+
+		/*
+		 * We need to re-schedule this check to be able to detect
+		 * if the voltage increases again during charging
+		 */
+		queue_delayed_work(di->fg_wq, &di->fg_low_bat_work,
+			round_jiffies(LOW_BAT_CHECK_INTERVAL));
+	} else {
+		di->flags.low_bat = false;
+		dev_warn(di->dev, "Battery voltage OK again\n");
+	}
+
+	/* This is needed to dispatch LOW_BAT */
+	ab8500_fg_check_capacity_limits(di, false);
+
+	/* Set this flag to check if LOW_BAT IRQ still occurs */
+	di->flags.low_bat_delay = false;
+}
+
+/**
  * ab8500_fg_instant_work() - Run the FG state machine instantly
  * @work:	pointer to the work_struct structure
  *
@@ -1236,17 +1280,15 @@ static irqreturn_t ab8500_fg_lowbatf_handler(int irq, void *_di)
 {
 	struct ab8500_fg *di = _di;
 
-	if (!di->flags.low_bat) {
-		dev_dbg(di->dev, "Battery voltage is below LOW threshold\n");
-
+	if (!di->flags.low_bat_delay) {
+		dev_warn(di->dev, "Battery voltage is below LOW threshold\n");
+		di->flags.low_bat_delay = true;
 		/*
-		 * This flag is checked in ab8500_fg_capacity_level and
-		 * POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL is propagated
-		 * to the application framework
+		 * Start a timer to check LOW_BAT again after some time
+		 * This is done to avoid shutdown on single voltage dips
 		 */
-		di->flags.low_bat = true;
-
-		queue_work(di->fg_wq, &di->fg_work);
+		queue_delayed_work(di->fg_wq, &di->fg_low_bat_work,
+			round_jiffies(LOW_BAT_CHECK_INTERVAL));
 	}
 	return IRQ_HANDLED;
 }
@@ -1594,6 +1636,10 @@ static int __devinit ab8500_fg_probe(struct platform_device *pdev)
 	INIT_DELAYED_WORK_DEFERRABLE(&di->fg_periodic_work,
 		ab8500_fg_periodic_work);
 
+	/* Work to check low battery condition */
+	INIT_DELAYED_WORK_DEFERRABLE(&di->fg_low_bat_work,
+		ab8500_fg_low_bat_work);
+
 	/* Initialize OVV, and other registers */
 	ret = ab8500_fg_init_hw_registers(di);
 	if (ret) {