i2c: Emulate SMBus block read over I2C

Let the I2C bus drivers emulate the SMBus Block Read and Block Process
Call transactions if they wish. This requires to define a new message
flag, which i2c-core will use to let the underlying I2C bus driver
know that the first received byte will specify the length of the read
message.

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 568dd1007b53..563c9651dd37 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -366,6 +366,7 @@ struct i2c_msg {
 #define I2C_M_REV_DIR_ADDR      0x2000
 #define I2C_M_IGNORE_NAK        0x1000
 #define I2C_M_NO_RD_ACK         0x0800
+#define I2C_M_RECV_LEN          0x0400 /* length will be first received byte */
         __u16 len;              /* msg length                           */
         __u8 *buf;              /* pointer to msg data                  */
 };