1 files changed, 20 insertions, 4 deletions

diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 9c90886..187ca08 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -26,6 +26,7 @@
 struct pwm_export {
 	struct device child;
 	struct pwm_device *pwm;
+	struct mutex lock;
 };
 
 static struct pwm_export *child_to_pwm_export(struct device *child)
@@ -53,7 +54,8 @@ static ssize_t period_store(struct device *child,
 			    struct device_attribute *attr,
 			    const char *buf, size_t size)
 {
-	struct pwm_device *pwm = child_to_pwm_device(child);
+	struct pwm_export *export = child_to_pwm_export(child);
+	struct pwm_device *pwm = export->pwm;
 	unsigned int val;
 	int ret;
 
@@ -61,7 +63,9 @@ static ssize_t period_store(struct device *child,
 	if (ret)
 		return ret;
 
+	mutex_lock(&export->lock);
 	ret = pwm_config(pwm, pwm_get_duty_cycle(pwm), val);
+	mutex_unlock(&export->lock);
 
 	return ret ? : size;
 }
@@ -79,7 +83,8 @@ static ssize_t duty_cycle_store(struct device *child,
 				struct device_attribute *attr,
 				const char *buf, size_t size)
 {
-	struct pwm_device *pwm = child_to_pwm_device(child);
+	struct pwm_export *export = child_to_pwm_export(child);
+	struct pwm_device *pwm = export->pwm;
 	unsigned int val;
 	int ret;
 
@@ -87,7 +92,9 @@ static ssize_t duty_cycle_store(struct device *child,
 	if (ret)
 		return ret;
 
+	mutex_lock(&export->lock);
 	ret = pwm_config(pwm, val, pwm_get_period(pwm));
+	mutex_unlock(&export->lock);
 
 	return ret ? : size;
 }
@@ -105,13 +112,16 @@ static ssize_t enable_store(struct device *child,
 			    struct device_attribute *attr,
 			    const char *buf, size_t size)
 {
-	struct pwm_device *pwm = child_to_pwm_device(child);
+	struct pwm_export *export = child_to_pwm_export(child);
+	struct pwm_device *pwm = export->pwm;
 	int val, ret;
 
 	ret = kstrtoint(buf, 0, &val);
 	if (ret)
 		return ret;
 
+	mutex_lock(&export->lock);
+
 	switch (val) {
 	case 0:
 		pwm_disable(pwm);
@@ -124,6 +134,8 @@ static ssize_t enable_store(struct device *child,
 		break;
 	}
 
+	mutex_unlock(&export->lock);
+
 	return ret ? : size;
 }
 
@@ -151,7 +163,8 @@ static ssize_t polarity_store(struct device *child,
 			      struct device_attribute *attr,
 			      const char *buf, size_t size)
 {
-	struct pwm_device *pwm = child_to_pwm_device(child);
+	struct pwm_export *export = child_to_pwm_export(child);
+	struct pwm_device *pwm = export->pwm;
 	enum pwm_polarity polarity;
 	int ret;
 
@@ -162,7 +175,9 @@ static ssize_t polarity_store(struct device *child,
 	else
 		return -EINVAL;
 
+	mutex_lock(&export->lock);
 	ret = pwm_set_polarity(pwm, polarity);
+	mutex_unlock(&export->lock);
 
 	return ret ? : size;
 }
@@ -203,6 +218,7 @@ static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
 	}
 
 	export->pwm = pwm;
+	mutex_init(&export->lock);
 
 	export->child.release = pwm_export_release;
 	export->child.parent = parent;