linux-kernel - [PATCH] extcon: arizona: Wait for any running HPDETs to complete on jack removal

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Date:   Tue, 24 Jan 2017 10:17:24 +0000
From:   Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
To:     <cw00.choi@...sung.com>
CC:     <myungjoo.ham@...sung.com>, <linux-kernel@...r.kernel.org>,
        <patches@...nsource.wolfsonmicro.com>
Subject: [PATCH] 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@...nsource.wolfsonmicro.com>
---
 drivers/extcon/extcon-arizona.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
index ed78b7c..218e378 100644
--- a/drivers/extcon/extcon-arizona.c
+++ b/drivers/extcon/extcon-arizona.c
@@ -1049,6 +1049,39 @@ 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 < 15; 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(20);
+	}
+
+	dev_err(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 +1188,8 @@ static irqreturn_t arizona_jackdet(int irq, void *data)
 					"Removal report failed: %d\n", ret);
 		}
 
+		arizona_hpdet_wait(info);
+
 		regmap_update_bits(arizona->regmap,
 				   ARIZONA_JACK_DETECT_DEBOUNCE,
 				   ARIZONA_MICD_CLAMP_DB | ARIZONA_JD1_DB,
-- 
2.1.4