Re: [PATCH 01/18] i2c: guarantee that I2C_M_RD will be 0x0001 forever

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Sun, 2016-04-03 at 20:44 +0200, Wolfram Sang wrote:
> 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.

Didn't see a comment as stated though.

> 
> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
> ---
>  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 b0a7dd61eb353a..adcbef4bff610a 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		
> 	*/
>  };

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy