i2c: Add support for nested i2c bus locking

This patch adds the 'level' field into the i2c_adapter structure, which is 
used to represent the 'logical' level of nesting for the purposes of 
lockdep. This field is then used in the i2c_transfer() function, to 
acquire the per-adapter bus_lock with correct nesting level.

Signed-off-by: Jiri Kosina <jikos@jikos.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 9b5d04768c2c..08df4169b411 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -216,6 +216,7 @@ struct i2c_adapter {
         int (*client_unregister)(struct i2c_client *);
 
         /* data fields that are valid for all devices   */
+        u8 level;                       /* nesting level for lockdep */
         struct mutex bus_lock;
         struct mutex clist_lock;