extcon: arizona: Suppress duplicate JACKDET reports

In cases where we see a brief (dis)connection of the jack detection signals
we may see a noop jack insertion or removal where the jack has returned to
the original state by the time the interrupt is serviced. Suppress these
events in order to save work and avoid confusing the rest of the code.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/extcon/extcon-arizona.c

@@ -39,6 +39,8 @@
 #define ARIZONA_ACCDET_MODE_HPL 1
 #define ARIZONA_ACCDET_MODE_HPR 2
 
+#define HPDET_DEBOUNCE 250
+
 struct arizona_extcon_info {
 	struct device *dev;
 	struct arizona *arizona;
@@ -46,6 +48,8 @@ struct arizona_extcon_info {
 	struct regulator *micvdd;
 	struct input_dev *input;
 
+	u16 last_jackdet;
+
 	int micd_mode;
 	const struct arizona_micd_config *micd_modes;
 	int micd_num_modes;
@@ -871,11 +875,12 @@ static irqreturn_t arizona_jackdet(int irq, void *data)
 	struct arizona_extcon_info *info = data;
 	struct arizona *arizona = info->arizona;
 	unsigned int val, present, mask;
+	bool cancelled;
 	int ret, i;
 
-	pm_runtime_get_sync(info->dev);
+	cancelled = cancel_delayed_work_sync(&info->hpdet_work);
 
-	cancel_delayed_work_sync(&info->hpdet_work);
+	pm_runtime_get_sync(info->dev);
 
 	mutex_lock(&info->lock);
 
@@ -896,7 +901,18 @@ static irqreturn_t arizona_jackdet(int irq, void *data)
 		return IRQ_NONE;
 	}
 
-	if ((val & mask) == present) {
+	val &= mask;
+	if (val == info->last_jackdet) {
+		dev_dbg(arizona->dev, "Suppressing duplicate JACKDET\n");
+		if (cancelled)
+			schedule_delayed_work(&info->hpdet_work,
+					      msecs_to_jiffies(HPDET_DEBOUNCE));
+
+		goto out;
+	}
+	info->last_jackdet = val;
+
+	if (info->last_jackdet == present) {
 		dev_dbg(arizona->dev, "Detected jack\n");
 		ret = extcon_set_cable_state_(&info->edev,
 					      ARIZONA_CABLE_MECHANICAL, true);
@@ -913,7 +929,7 @@ static irqreturn_t arizona_jackdet(int irq, void *data)
 			arizona_start_mic(info);
 		} else {
 			schedule_delayed_work(&info->hpdet_work,
-					      msecs_to_jiffies(250));
+					      msecs_to_jiffies(HPDET_DEBOUNCE));
 		}
 
 		regmap_update_bits(arizona->regmap,
@@ -953,6 +969,7 @@ static irqreturn_t arizona_jackdet(int irq, void *data)
 		     ARIZONA_JD1_FALL_TRIG_STS |
 		     ARIZONA_JD1_RISE_TRIG_STS);
 
+out:
 	mutex_unlock(&info->lock);
 
 	pm_runtime_mark_last_busy(info->dev);
@@ -1012,6 +1029,7 @@ static int arizona_extcon_probe(struct platform_device *pdev)
 	mutex_init(&info->lock);
 	info->arizona = arizona;
 	info->dev = &pdev->dev;
+	info->last_jackdet = ~(ARIZONA_MICD_CLAMP_STS | ARIZONA_JD1_STS);
 	INIT_DELAYED_WORK(&info->hpdet_work, arizona_hpdet_work);
 	platform_set_drvdata(pdev, info);