misc: tsl2550: replace simple_strtoul to kstrtoul

The function simple_strtoul performs no error checking
in scenarios where the input value overflows the intended
output variable.

We can replace the use of the simple_strtoul with the safer
alternatives kstrtoul.

Signed-off-by: Hongbo Li <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Hongbo Li

drivers/misc/tsl2550.c

@@ -185,10 +185,10 @@ static ssize_t tsl2550_store_power_state(struct device *dev,
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct tsl2550_data *data = i2c_get_clientdata(client);
-	unsigned long val = simple_strtoul(buf, NULL, 10);
+	unsigned long val;
 	int ret;
 
-	if (val > 1)
+	if (kstrtoul(buf, 10, &val) || val > 1)
 		return -EINVAL;
 
 	mutex_lock(&data->update_lock);
@@ -217,10 +217,10 @@ static ssize_t tsl2550_store_operating_mode(struct device *dev,
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct tsl2550_data *data = i2c_get_clientdata(client);
-	unsigned long val = simple_strtoul(buf, NULL, 10);
+	unsigned long val;
 	int ret;
 
-	if (val > 1)
+	if (kstrtoul(buf, 10, &val) || val > 1)
 		return -EINVAL;
 
 	if (data->power_state == 0)