OMAP: DSS2: Taal: Add locks to protect taal data access

Avoid potential race conditions in sysfs access to taal data.
Signed-off-by: NJani Nikula <ext-jani.1.nikula@nokia.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@nokia.com>

drivers/video/omap2/displays/panel-taal.c

@@ -364,6 +364,8 @@ static ssize_t taal_num_errors_show(struct device *dev,
 	u8 errors;
 	int r;
 
+	mutex_lock(&td->lock);
+
 	if (td->enabled) {
 		dsi_bus_lock();
 		r = taal_dcs_read_1(DCS_READ_NUM_ERRORS, &errors);
@@ -372,6 +374,8 @@ static ssize_t taal_num_errors_show(struct device *dev,
 		r = -ENODEV;
 	}
 
+	mutex_unlock(&td->lock);
+
 	if (r)
 		return r;
 
@@ -386,6 +390,8 @@ static ssize_t taal_hw_revision_show(struct device *dev,
 	u8 id1, id2, id3;
 	int r;
 
+	mutex_lock(&td->lock);
+
 	if (td->enabled) {
 		dsi_bus_lock();
 		r = taal_get_id(&id1, &id2, &id3);
@@ -394,6 +400,8 @@ static ssize_t taal_hw_revision_show(struct device *dev,
 		r = -ENODEV;
 	}
 
+	mutex_unlock(&td->lock);
+
 	if (r)
 		return r;
 
@@ -443,6 +451,8 @@ static ssize_t store_cabc_mode(struct device *dev,
 	if (i == ARRAY_SIZE(cabc_modes))
 		return -EINVAL;
 
+	mutex_lock(&td->lock);
+
 	if (td->enabled) {
 		dsi_bus_lock();
 		if (!td->cabc_broken)
@@ -452,6 +462,8 @@ static ssize_t store_cabc_mode(struct device *dev,
 
 	td->cabc_mode = i;
 
+	mutex_unlock(&td->lock);
+
 	return count;
 }