aio: added configuration within platform data.

* Allows for different bit shifting for each platform.
* New functions added for obtaining this information
* mraa_adc_raw_bits
* mraa_adc_supported_bits

* Update board information to include this. AIO module changed to allow
* use of the new board data

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>

api/mraa/aio.h

@@ -44,9 +44,6 @@ extern "C" {
 #include "common.h"
 #include "gpio.h"
 
-#define ADC_RAW_RESOLUTION_BITS         (12)
-#define ADC_SUPPORTED_RESOLUTION_BITS   (10)
-
 /**
  * Opaque pointer definition to the internal struct _aio. This context refers
  * to one single AIO pin on the board.

api/mraa/common.h

@@ -164,6 +164,8 @@ typedef struct {
     unsigned int spi_bus_count; /**< Usable spi Count */
     mraa_spi_bus_t spi_bus[6];       /**< Array of spi */
     unsigned int def_spi_bus; /**< Position in array of defult spi bus */
+    unsigned int adc_raw; /**< ADC raw bit value */
+    unsigned int adc_supported; /**< ADC supported bit value */
     mraa_pininfo_t* pins;     /**< Pointer to pin array */
     /*@}*/
 } mraa_board_t;
@@ -193,6 +195,20 @@ mraa_result_t mraa_init();
  */
 mraa_boolean_t mraa_pin_mode_test(int pin, mraa_pinmodes_t mode);
 
+/**
+ * Check the board's  bit size when reading the value
+ *
+ * @return raw bits being read from kernel module. zero if no ADC
+ */
+unsigned int mraa_adc_raw_bits();
+
+/**
+ * Return value that the raw value should be shifted to. Zero if no ADC
+ *
+ * @return return actual bit size the adc value should be understood as.
+ */
+unsigned int mraa_adc_supported_bits();
+
 #ifdef __cplusplus
 }
 #endif