i2c: introduce helper function to get 8 bit address from a message

Drivers do this in various ways, let's use one standard way of doing it.
Note: I2C_M_RD is bit 0, so the code could be simplified. To be extremly
robust and to advertise good coding practices, I still use the ternary
operator and let the compilers do the optimizing job.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 200cf13b00f620dae9ea8ecbd15e71d26ffb4a3a..c30833b7b0730d1ee849af4aad40f3f86124ae11 100644 (file)
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -654,6 +654,11 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap)
        return adap->nr;
 }
 
+static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
+{
+       return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
+}
+
 /**
  * module_i2c_driver() - Helper macro for registering a modular I2C driver
  * @__i2c_driver: i2c_driver struct