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Commit e28b1245 authored by Wolfram Sang's avatar Wolfram Sang
Browse files

i2c: guarantee that I2C_M_RD will be 0x0001 forever 



There is code out there in user space and kernel space which relies on
I2C_M_RD being bit 0 to simplify their bit operations. Add a comment to
make sure this will never break. Do proper sorting of the defines while
we are here.

Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent bf162006

include/uapi/linux/i2c.h

+7 −6
Original line number Diff line number Diff line
@@ -68,14 +68,15 @@ 
struct i2c_msg {

	__u16 addr;	/* slave address			*/

	__u16 flags;

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

#define I2C_M_RD		0x0001	/* read data, from slave to master */

#define I2C_M_STOP		0x8000	/* if I2C_FUNC_PROTOCOL_MANGLING */

#define I2C_M_NOSTART		0x4000	/* if I2C_FUNC_NOSTART */

#define I2C_M_REV_DIR_ADDR	0x2000	/* if I2C_FUNC_PROTOCOL_MANGLING */

#define I2C_M_IGNORE_NAK	0x1000	/* if I2C_FUNC_PROTOCOL_MANGLING */

#define I2C_M_NO_RD_ACK		0x0800	/* if I2C_FUNC_PROTOCOL_MANGLING */

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

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

#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 */

#define I2C_M_REV_DIR_ADDR	0x2000	/* if I2C_FUNC_PROTOCOL_MANGLING */

#define I2C_M_NOSTART		0x4000	/* if I2C_FUNC_NOSTART */

#define I2C_M_STOP		0x8000	/* if I2C_FUNC_PROTOCOL_MANGLING */

	__u16 len;		/* msg length				*/

	__u8 *buf;		/* pointer to msg data			*/

};