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>

1 files changed, 12 insertions, 2 deletions

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;
 }