1 files changed, 34 insertions, 25 deletions

diff --git a/drivers/hwmon/ams/ams-input.c b/drivers/hwmon/ams/ams-input.c
index 48dbf7d6a66d..8a712392cd38 100644
--- a/drivers/hwmon/ams/ams-input.c
+++ b/drivers/hwmon/ams/ams-input.c
@@ -27,6 +27,8 @@ static unsigned int invert;
 module_param(invert, bool, S_IWUSR | S_IRUGO);
 MODULE_PARM_DESC(invert, "Invert input data on X and Y axis");
 
+static DEFINE_MUTEX(ams_input_mutex);
+
 static void ams_idev_poll(struct input_polled_dev *dev)
 {
         struct input_dev *idev = dev->input;
@@ -50,13 +52,11 @@ static void ams_idev_poll(struct input_polled_dev *dev)
 }
 
 /* Call with ams_info.lock held! */
-static void ams_input_enable(void)
+static int ams_input_enable(void)
 {
         struct input_dev *input;
         s8 x, y, z;
-
-        if (ams_info.idev)
-                return;
+        int error;
 
         ams_sensors(&x, &y, &z);
         ams_info.xcalib = x;
@@ -65,7 +65,7 @@ static void ams_input_enable(void)
 
         ams_info.idev = input_allocate_polled_device();
         if (!ams_info.idev)
-                return;
+                return -ENOMEM;
 
         ams_info.idev->poll = ams_idev_poll;
         ams_info.idev->poll_interval = 25;
@@ -84,14 +84,18 @@ static void ams_input_enable(void)
         set_bit(EV_KEY, input->evbit);
         set_bit(BTN_TOUCH, input->keybit);
 
-        if (input_register_polled_device(ams_info.idev)) {
+        error = input_register_polled_device(ams_info.idev);
+        if (error) {
                 input_free_polled_device(ams_info.idev);
                 ams_info.idev = NULL;
-                return;
+                return error;
         }
+
+        joystick = 1;
+
+        return 0;
 }
 
-/* Call with ams_info.lock held! */
 static void ams_input_disable(void)
 {
         if (ams_info.idev) {
@@ -99,6 +103,8 @@ static void ams_input_disable(void)
                 input_free_polled_device(ams_info.idev);
                 ams_info.idev = NULL;
         }
+
+        joystick = 0;
 }
 
 static ssize_t ams_input_show_joystick(struct device *dev,
@@ -110,39 +116,42 @@ static ssize_t ams_input_show_joystick(struct device *dev,
 static ssize_t ams_input_store_joystick(struct device *dev,
         struct device_attribute *attr, const char *buf, size_t count)
 {
-        if (sscanf(buf, "%d\n", &joystick) != 1)
+        unsigned long enable;
+        int error = 0;
+
+        if (strict_strtoul(buf, 0, &enable) || enable > 1)
                 return -EINVAL;
 
-        mutex_lock(&ams_info.lock);
+        mutex_lock(&ams_input_mutex);
 
-        if (joystick)
-                ams_input_enable();
-        else
-                ams_input_disable();
+        if (enable != joystick) {
+                if (enable)
+                        error = ams_input_enable();
+                else
+                        ams_input_disable();
+        }
 
-        mutex_unlock(&ams_info.lock);
+        mutex_unlock(&ams_input_mutex);
 
-        return count;
+        return error ? error : count;
 }
 
 static DEVICE_ATTR(joystick, S_IRUGO | S_IWUSR,
         ams_input_show_joystick, ams_input_store_joystick);
 
-/* Call with ams_info.lock held! */
 int ams_input_init(void)
 {
-        int result;
-
-        result = device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
-
-        if (!result && joystick)
+        if (joystick)
                 ams_input_enable();
-        return result;
+
+        return device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
 }
 
-/* Call with ams_info.lock held! */
 void ams_input_exit(void)
 {
-        ams_input_disable();
         device_remove_file(&ams_info.of_dev->dev, &dev_attr_joystick);
+
+        mutex_lock(&ams_input_mutex);
+        ams_input_disable();
+        mutex_unlock(&ams_input_mutex);
 }