From e28b124564e648d933337a0708dae1323c518af7 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Sun, 3 Apr 2016 20:44:44 +0200 Subject: [PATCH] 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: Andy Shevchenko Signed-off-by: Wolfram Sang --- include/uapi/linux/i2c.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h index b0a7dd61eb35..adcbef4bff61 100644 --- a/include/uapi/linux/i2c.h +++ b/include/uapi/linux/i2c.h @@ -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 */ }; -- 2.39.5