From 521a72e1f2e8141d78e7699eaacda24e308ed428 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Sat, 4 Nov 2017 21:20:01 +0100 Subject: [PATCH] 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: Jonathan Cameron Signed-off-by: Wolfram Sang Signed-off-by: Wolfram Sang --- 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 fe64803..f71a175 100644 --- a/include/uapi/linux/i2c.h +++ b/include/uapi/linux/i2c.h @@ -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 */ -- 2.7.4