linux-kernel - [PATCH 08/16] extcon: arizona: Check we report a valid impedance

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Message-Id: <1364902368-1123-8-git-send-email-broonie@opensource.wolfsonmicro.com>
Date:	Tue,  2 Apr 2013 12:32:40 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	MyungJoo Ham <myungjoo.ham@...sung.com>,
	Chanwoo Choi <cw00.choi@...sung.com>
Cc:	linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com,
	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH 08/16] extcon: arizona: Check we report a valid impedance

From: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>

Occasionally we can trigger an interrupt before we have completed
impedance measurement, although the valid bit will still be set. This
patch spins reading the impedance value until a valid value is seen.

Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
---
 drivers/extcon/extcon-arizona.c |   28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
index 9e4bffe..4022fe2 100644
--- a/drivers/extcon/extcon-arizona.c
+++ b/drivers/extcon/extcon-arizona.c
@@ -737,22 +737,30 @@ static irqreturn_t arizona_micdet(int irq, void *data)
 {
 	struct arizona_extcon_info *info = data;
 	struct arizona *arizona = info->arizona;
-	unsigned int val, lvl;
+	unsigned int val = 0, lvl;
 	int ret, i, key;
 
 	mutex_lock(&info->lock);
 
-	ret = regmap_read(arizona->regmap, ARIZONA_MIC_DETECT_3, &val);
-	if (ret != 0) {
-		dev_err(arizona->dev, "Failed to read MICDET: %d\n", ret);
-		mutex_unlock(&info->lock);
-		return IRQ_NONE;
-	}
+	for (i = 0; i < 10 && !(val & 0x7fc); i++) {
+		ret = regmap_read(arizona->regmap, ARIZONA_MIC_DETECT_3, &val);
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to read MICDET: %d\n", ret);
+			mutex_unlock(&info->lock);
+			return IRQ_NONE;
+		}
+
+		dev_dbg(arizona->dev, "MICDET: %x\n", val);
 
-	dev_dbg(arizona->dev, "MICDET: %x\n", val);
+		if (!(val & ARIZONA_MICD_VALID)) {
+			dev_warn(arizona->dev, "Microphone detection state invalid\n");
+			mutex_unlock(&info->lock);
+			return IRQ_NONE;
+		}
+	}
 
-	if (!(val & ARIZONA_MICD_VALID)) {
-		dev_warn(arizona->dev, "Microphone detection state invalid\n");
+	if (i == 10 && !(val & 0x7fc)) {
+		dev_err(arizona->dev, "Failed to get valid MICDET value\n");
 		mutex_unlock(&info->lock);
 		return IRQ_NONE;
 	}
-- 
1.7.10.4

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