i2c: Remove i2c_algorithm.algo_control()

This removes:

 - An effectively unused hook:  i2c_algorithm.algo_control.

 - The i2c_control() call, used only by i2c-dev to call that
   unused hook or set two barely supported adapter params.

   (That param setting moves into i2c-dev.c ... still iffy
   due to lack of locking, but no other changes.)

As shown by diffstat, this is a net code shrink.  It also reduces the
complexity of the I2C adapter and /dev interfaces.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 12 insertions, 31 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 5e58b5641a35..e73d58c43f38 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -931,28 +931,6 @@ int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
 }
 EXPORT_SYMBOL(i2c_master_recv);
 
-int i2c_control(struct i2c_client *client,
-        unsigned int cmd, unsigned long arg)
-{
-        int ret = 0;
-        struct i2c_adapter *adap = client->adapter;
-
-        dev_dbg(&client->adapter->dev, "i2c ioctl, cmd: 0x%x, arg: %#lx\n", cmd, arg);
-        switch (cmd) {
-                case I2C_RETRIES:
-                        adap->retries = arg;
-                        break;
-                case I2C_TIMEOUT:
-                        adap->timeout = arg;
-                        break;
-                default:
-                        if (adap->algo->algo_control!=NULL)
-                                ret = adap->algo->algo_control(adap,cmd,arg);
-        }
-        return ret;
-}
-EXPORT_SYMBOL(i2c_control);
-
 /* ----------------------------------------------------
  * the i2c address scanning function
  * Will not work for 10-bit addresses!
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index df6e14c192d6..5a15e50748de 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -354,9 +354,19 @@ static int i2cdev_ioctl(struct inode *inode, struct file *file,
                                 return -EFAULT;
                 }
                 return res;
-
+        case I2C_RETRIES:
+                client->adapter->retries = arg;
+                break;
+        case I2C_TIMEOUT:
+                client->adapter->timeout = arg;
+                break;
         default:
-                return i2c_control(client,cmd,arg);
+                /* NOTE:  returning a fault code here could cause trouble
+                 * in buggy userspace code.  Some old kernel bugs returned
+                 * zero in this case, and userspace code might accidentally
+                 * have depended on that bug.
+                 */
+                return -ENOTTY;
         }
         return 0;
 }
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 8fc4310f071b..ae477b3106a2 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -290,9 +290,6 @@ struct i2c_algorithm {
                            unsigned short flags, char read_write,
                            u8 command, int size, union i2c_smbus_data * data);
 
-        /* --- ioctl like call to set div. parameters. */
-        int (*algo_control)(struct i2c_adapter *, unsigned int, unsigned long);
-
         /* To determine what the adapter supports */
         u32 (*functionality) (struct i2c_adapter *);
 };
@@ -416,10 +413,6 @@ extern int i2c_probe(struct i2c_adapter *adapter,
                 struct i2c_client_address_data *address_data,
                 int (*found_proc) (struct i2c_adapter *, int, int));
 
-/* An ioctl like call to set div. parameters of the adapter.
- */
-extern int i2c_control(struct i2c_client *,unsigned int, unsigned long);
-
 extern struct i2c_adapter* i2c_get_adapter(int id);
 extern void i2c_put_adapter(struct i2c_adapter *adap);