iio: accel: mma9551: split driver to expose mma955x api

Freescale has the MMA955xL family of devices that use the
same communication protocol (based on i2c messages):
http://www.freescale.com/files/sensors/doc/data_sheet/MMA955xL.pdf.

To support more devices from this family, we need to split the
mma9551 driver so we can export the common functions that will
be used by other mma955x drivers.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Reviewed-by: Vlad Dogaru <vlad.dogaru@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/Kconfig

@@ -111,9 +111,14 @@ config KXCJK1013
 	  To compile this driver as a module, choose M here: the module will
 	  be called kxcjk-1013.
 
+config MMA9551_CORE
+	tristate
+
 config MMA9551
 	tristate "Freescale MMA9551L Intelligent Motion-Sensing Platform Driver"
 	depends on I2C
+	select MMA9551_CORE
+
 	help
 	  Say yes here to build support for the Freescale MMA9551L
 	  Intelligent Motion-Sensing Platform Driver.

drivers/iio/accel/Makefile

@@ -9,7 +9,9 @@ obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
 obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
 obj-$(CONFIG_KXSD9)	+= kxsd9.o
 obj-$(CONFIG_MMA8452)	+= mma8452.o
-obj-$(CONFIG_MMA9551)	+= mma9551.o
+
+obj-$(CONFIG_MMA9551_CORE)	+= mma9551_core.o
+obj-$(CONFIG_MMA9551)		+= mma9551.o
 
 obj-$(CONFIG_IIO_ST_ACCEL_3AXIS) += st_accel.o
 st_accel-y := st_accel_core.o