Optimize device tranactions using i2c transfers versus multiple
possibly racey i2c_smbus_* function calls, and only one transaction
for distance measurement. Falls back to smbus method if i2c
functionality isn't available.
Signed-off-by: NMatt Ranostay <mranostay@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>