mfd: Use kstrtoul_from_user in ab3550

This patch replaces the code for getting an unsigned long from a
userspace buffer by a simple call to kstroul_from_user.
This makes it easier to read and less error prone.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 11 insertions, 30 deletions

diff --git a/drivers/mfd/ab3550-core.c b/drivers/mfd/ab3550-core.c
index 3d7dce671b93..56ba1943c91d 100644
--- a/drivers/mfd/ab3550-core.c
+++ b/drivers/mfd/ab3550-core.c
@@ -879,20 +879,13 @@ static ssize_t ab3550_bank_write(struct file *file,
         size_t count, loff_t *ppos)
 {
         struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
-        char buf[32];
-        int buf_size;
         unsigned long user_bank;
         int err;
 
         /* Get userspace string and assure termination */
-        buf_size = min(count, (sizeof(buf) - 1));
-        if (copy_from_user(buf, user_buf, buf_size))
-                return -EFAULT;
-        buf[buf_size] = 0;
-
-        err = strict_strtoul(buf, 0, &user_bank);
+        err = kstrtoul_from_user(user_buf, count, 0, &user_bank);
         if (err)
-                return -EINVAL;
+                return err;
 
         if (user_bank >= AB3550_NUM_BANKS) {
                 dev_err(&ab->i2c_client[0]->dev,
@@ -902,7 +895,7 @@ static ssize_t ab3550_bank_write(struct file *file,
 
         ab->debug_bank = user_bank;
 
-        return buf_size;
+        return count;
 }
 
 static int ab3550_address_print(struct seq_file *s, void *p)
@@ -923,27 +916,21 @@ static ssize_t ab3550_address_write(struct file *file,
         size_t count, loff_t *ppos)
 {
         struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
-        char buf[32];
-        int buf_size;
         unsigned long user_address;
         int err;
 
         /* Get userspace string and assure termination */
-        buf_size = min(count, (sizeof(buf) - 1));
-        if (copy_from_user(buf, user_buf, buf_size))
-                return -EFAULT;
-        buf[buf_size] = 0;
-
-        err = strict_strtoul(buf, 0, &user_address);
+        err = kstrtoul_from_user(user_buf, count, 0, &user_address);
         if (err)
-                return -EINVAL;
+                return err;
+
         if (user_address > 0xff) {
                 dev_err(&ab->i2c_client[0]->dev,
                         "debugfs error input > 0xff\n");
                 return -EINVAL;
         }
         ab->debug_address = user_address;
-        return buf_size;
+        return count;
 }
 
 static int ab3550_val_print(struct seq_file *s, void *p)
@@ -971,21 +958,15 @@ static ssize_t ab3550_val_write(struct file *file,
         size_t count, loff_t *ppos)
 {
         struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
-        char buf[32];
-        int buf_size;
         unsigned long user_val;
         int err;
         u8 regvalue;
 
         /* Get userspace string and assure termination */
-        buf_size = min(count, (sizeof(buf)-1));
-        if (copy_from_user(buf, user_buf, buf_size))
-                return -EFAULT;
-        buf[buf_size] = 0;
-
-        err = strict_strtoul(buf, 0, &user_val);
+        err = kstrtoul_from_user(user_buf, count, 0, &user_val);
         if (err)
-                return -EINVAL;
+                return err;
+
         if (user_val > 0xff) {
                 dev_err(&ab->i2c_client[0]->dev,
                         "debugfs error input > 0xff\n");
@@ -1002,7 +983,7 @@ static ssize_t ab3550_val_write(struct file *file,
         if (err)
                 return -EINVAL;
 
-        return buf_size;
+        return count;
 }
 
 static const struct file_operations ab3550_bank_fops = {