extcon: arizona: Check we report a valid impedance

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@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 18 insertions, 10 deletions

diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
index 9e4bffe610b6..4022fe207926 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;
         }