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| author |   Wolfram Sang <wsa@the-dreams.de> | 2016-04-03 20:44:44 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2016-04-11 18:54:59 +0200 |
| commit | e28b124564e648d933337a0708dae1323c518af7 (patch) | |
| tree | 616a6cfaedc904c000f72c725009fc8a0c4642f7 /include/uapi/linux/i2c.h | |
| parent | Linux 4.6-rc3 (diff) | |
| download | linux-dev-e28b124564e648d933337a0708dae1323c518af7.tar.xz linux-dev-e28b124564e648d933337a0708dae1323c518af7.zip | |
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 <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'include/uapi/linux/i2c.h')
| -rw-r--r-- | include/uapi/linux/i2c.h | 13 |
1 files 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 */ }; |