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>
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index b0a7dd6..adcbef4 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 */
};