iio: Add Freescale MMA8452Q 3-axis accelerometer driver

3-axis accelerometer sensor (2/4/8 g) with 12-bit resolution
and I2C interface

many extra features are unsupported (freefall detection, orientation
change, autosleep)

datasheet is here:
http://cache.freescale.com/files/sensors/doc/data_sheet/MMA8452Q.pdf

v2: (thanks to Jonathan Cameron)
* use ARRAY_SIZE()
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/Kconfig

@@ -65,4 +65,16 @@ config KXSD9
 	  Say yes here to build support for the Kionix KXSD9 accelerometer.
 	  Currently this only supports the device via an SPI interface.
 
+config MMA8452
+	tristate "Freescale MMA8452Q Accelerometer Driver"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes here to build support for the Freescale MMA8452Q 3-axis
+	  accelerometer.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called mma8452.
+
 endmenu

drivers/iio/accel/Makefile

@@ -6,6 +6,7 @@
 obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
 obj-$(CONFIG_KXSD9)	+= kxsd9.o
+obj-$(CONFIG_MMA8452)	+= mma8452.o
 
 obj-$(CONFIG_IIO_ST_ACCEL_3AXIS) += st_accel.o
 st_accel-y := st_accel_core.o