Commit 521a72e1 authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

i2c: add a message flag for DMA safe buffers 



I2C has no requirement that the buffer of a message needs to be DMA
safe. In case it is, it can now be flagged, so drivers wishing to
do DMA can use the buffer directly.

Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 14911c6f

include/uapi/linux/i2c.h

+3 −0
Original line number Diff line number Diff line
@@ -72,6 +72,9 @@ struct i2c_msg { 
#define I2C_M_RD		0x0001	/* read data, from slave to master */

					/* I2C_M_RD is guaranteed to be 0x0001! */

#define I2C_M_TEN		0x0010	/* this is a ten bit chip address */

#define I2C_M_DMA_SAFE		0x0200	/* the buffer of this message is DMA safe */

					/* makes only sense in kernelspace */

					/* userspace buffers are copied anyway */

#define I2C_M_RECV_LEN		0x0400	/* length will be first received byte */

#define I2C_M_NO_RD_ACK		0x0800	/* if I2C_FUNC_PROTOCOL_MANGLING */

#define I2C_M_IGNORE_NAK	0x1000	/* if I2C_FUNC_PROTOCOL_MANGLING */