i2c: Document the message size limit

i2c_master_send & i2c_master_recv do not support more than 64 kb
transfer, since msg.len is u16.

Signed-off-by: Zhangfei Gao <zgao6@marvell.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index 0a74603eb671..3219ee0dbfef 100644
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -318,8 +318,9 @@ Plain I2C communication
 These routines read and write some bytes from/to a client. The client
 contains the i2c address, so you do not have to include it. The second
 parameter contains the bytes to read/write, the third the number of bytes
-to read/write (must be less than the length of the buffer.) Returned is
-the actual number of bytes read/written.
+to read/write (must be less than the length of the buffer, also should be
+less than 64k since msg.len is u16.) Returned is the actual number of bytes
+read/written.
 
         int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msg,
                          int num);