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.
Signed-off-by: Wolfram Sang <wsa+rene...@sang-engineering.com>
---
include/uapi/linux/i2c.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index 009e27bb9abe19..1c683cb319e4b7 100644
--- a/include/uapi/linux/i2c.h
+++ b/include/uapi/linux/i2c.h
@@ -71,6 +71,9 @@ 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 */
--
2.11.0
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