[PATCH] i2c: Rework client usage count, 3 of 3

Do not limit the usage count of i2c clients to 1. In other words,
change the client usage count behavior from the old I2C_CLIENT_ALLOW_USE
to the old I2C_CLIENT_ALLOW_MULTIPLE_USE. The rationale is that no
driver actually needs the limiting behavior, and the unlimiting
behavior is slightly easier to implement.

Update the documentation to reflect this change.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/i2c/porting-clients

@@ -92,6 +92,7 @@ Technical changes:
   Drop client->id.
   Drop any 24RF08 corruption prevention you find, as this is now done
   at the i2c-core level, and doing it twice voids it.
+  Don't add I2C_CLIENT_ALLOW_USE to client->flags, it's the default now.
 
 * [Init] Limits must not be set by the driver (can be done later in
   user-space). Chip should not be reset default (although a module

drivers/i2c/i2c-core.c

@@ -497,14 +497,9 @@ int i2c_use_client(struct i2c_client *client)
 	if (ret)
 		return ret;
 
-	if (client->usage_count > 0)
-		goto busy;
 	client->usage_count++;
 
 	return 0;
- busy:
-	i2c_dec_use_client(client);
-	return -EBUSY;
 }
 
 int i2c_release_client(struct i2c_client *client)

include/linux/i2c.h

@@ -307,9 +307,7 @@ extern struct i2c_client *i2c_get_client(int driver_id, int adapter_id,
    extern struct i2c_client *i2c_get_client(int,int,struct i2c_client *);
    to make sure that client-struct is valid and that it is okay to access
    the i2c-client. 
-   returns -EACCES if client doesn't allow use (default)
-   returns -EBUSY if client doesn't allow multiple use (default) and 
-   usage_count >0 */
+   returns -ENODEV if client has gone in the meantime */
 extern int i2c_use_client(struct i2c_client *);
 extern int i2c_release_client(struct i2c_client *);