extcon: arizona: Wait for any running HPDETs to complete on jack removal

As the HPDET can't be aborted mid way through we should not allow any new
insertion to be processed until the previous HPDET has finished. It is very
unlikely but with low enough debounce settings you could start a new HPDET
before the old one has completed, which results in an erroneous reading.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/extcon-arizona.c

@@ -51,6 +51,9 @@
 #define HPDET_DEBOUNCE 500
 #define DEFAULT_MICD_TIMEOUT 2000
 
+#define ARIZONA_HPDET_WAIT_COUNT 15
+#define ARIZONA_HPDET_WAIT_DELAY_MS 20
+
 #define QUICK_HEADPHONE_MAX_OHM 3
 #define MICROPHONE_MIN_OHM      1257
 #define MICROPHONE_MAX_OHM      30000
@@ -1049,6 +1052,40 @@ static void arizona_hpdet_work(struct work_struct *work)
 	mutex_unlock(&info->lock);
 }
 
+static int arizona_hpdet_wait(struct arizona_extcon_info *info)
+{
+	struct arizona *arizona = info->arizona;
+	unsigned int val;
+	int i, ret;
+
+	for (i = 0; i < ARIZONA_HPDET_WAIT_COUNT; i++) {
+		ret = regmap_read(arizona->regmap, ARIZONA_HEADPHONE_DETECT_2,
+				&val);
+		if (ret) {
+			dev_err(arizona->dev,
+				"Failed to read HPDET state: %d\n", ret);
+			return ret;
+		}
+
+		switch (info->hpdet_ip_version) {
+		case 0:
+			if (val & ARIZONA_HP_DONE)
+				return 0;
+			break;
+		default:
+			if (val & ARIZONA_HP_DONE_B)
+				return 0;
+			break;
+		}
+
+		msleep(ARIZONA_HPDET_WAIT_DELAY_MS);
+	}
+
+	dev_warn(arizona->dev, "HPDET did not appear to complete\n");
+
+	return -ETIMEDOUT;
+}
+
 static irqreturn_t arizona_jackdet(int irq, void *data)
 {
 	struct arizona_extcon_info *info = data;
@@ -1155,6 +1192,15 @@ static irqreturn_t arizona_jackdet(int irq, void *data)
 					"Removal report failed: %d\n", ret);
 		}
 
+		/*
+		 * If the jack was removed during a headphone detection we
+		 * need to wait for the headphone detection to finish, as
+		 * it can not be aborted. We don't want to be able to start
+		 * a new headphone detection from a fresh insert until this
+		 * one is finished.
+		 */
+		arizona_hpdet_wait(info);
+
 		regmap_update_bits(arizona->regmap,
 				   ARIZONA_JACK_DETECT_DEBOUNCE,
 				   ARIZONA_MICD_CLAMP_DB | ARIZONA_JD1_DB,