power: supply: ds2781: use kobj_to_dev()

Use kobj_to_dev() instead of open-coding it
Signed-off-by: dongjian <dongjian@yulong.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/ds2781_battery.c

@@ -626,7 +626,7 @@ static ssize_t ds2781_read_param_eeprom_bin(struct file *filp,
 				struct bin_attribute *bin_attr,
 				char *buf, loff_t off, size_t count)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct power_supply *psy = to_power_supply(dev);
 	struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
 
@@ -639,7 +639,7 @@ static ssize_t ds2781_write_param_eeprom_bin(struct file *filp,
 				struct bin_attribute *bin_attr,
 				char *buf, loff_t off, size_t count)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct power_supply *psy = to_power_supply(dev);
 	struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
 	int ret;
@@ -671,7 +671,7 @@ static ssize_t ds2781_read_user_eeprom_bin(struct file *filp,
 				struct bin_attribute *bin_attr,
 				char *buf, loff_t off, size_t count)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct power_supply *psy = to_power_supply(dev);
 	struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
 
@@ -685,7 +685,7 @@ static ssize_t ds2781_write_user_eeprom_bin(struct file *filp,
 				struct bin_attribute *bin_attr,
 				char *buf, loff_t off, size_t count)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct power_supply *psy = to_power_supply(dev);
 	struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
 	int ret;