hwmon: (gpio-fan) Add missing mutex locks

set_fan_speed() is expected to be called with fan_data->lock being locked.
Add locking for proper synchronization.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20250210145934.761280-3-alexander.stein@ew.tq-group.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Author: tq-steina

drivers/hwmon/gpio-fan.c

@@ -393,7 +393,12 @@ static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
 	if (state >= fan_data->num_speed)
 		return -EINVAL;
 
+	mutex_lock(&fan_data->lock);
+
 	set_fan_speed(fan_data, state);
+
+	mutex_unlock(&fan_data->lock);
+
 	return 0;
 }
 
@@ -489,7 +494,11 @@ MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
 
 static void gpio_fan_stop(void *data)
 {
+	struct gpio_fan_data *fan_data = data;
+
+	mutex_lock(&fan_data->lock);
 	set_fan_speed(data, 0);
+	mutex_unlock(&fan_data->lock);
 }
 
 static int gpio_fan_probe(struct platform_device *pdev)
@@ -562,7 +571,9 @@ static int gpio_fan_suspend(struct device *dev)
 
 	if (fan_data->gpios) {
 		fan_data->resume_speed = fan_data->speed_index;
+		mutex_lock(&fan_data->lock);
 		set_fan_speed(fan_data, 0);
+		mutex_unlock(&fan_data->lock);
 	}
 
 	return 0;
@@ -572,8 +583,11 @@ static int gpio_fan_resume(struct device *dev)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 
-	if (fan_data->gpios)
+	if (fan_data->gpios) {
+		mutex_lock(&fan_data->lock);
 		set_fan_speed(fan_data, fan_data->resume_speed);
+		mutex_unlock(&fan_data->lock);
+	}
 
 	return 0;
 }