i2c: allow binary strings as parameters to write() functions in scripting

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/i2c.hpp

@@ -95,8 +95,8 @@ class I2c {
          * @param length Size of read
          * @return length of the read or 0 if failed
          */
-        int read(unsigned char * data, int length) {
-            return mraa_i2c_read(m_i2c, data, length);
+        int read(char * data, size_t length) {
+            return mraa_i2c_read(m_i2c, (uint8_t*) data, (int) length);
         }
         /**
          * Write one byte to the bus
@@ -105,8 +105,8 @@ class I2c {
          * @param length Size of buffer to send
          * @return Result of operation
          */
-        mraa_result_t write(const unsigned char* data, int length) {
-            return mraa_i2c_write(m_i2c, data, length);
+        mraa_result_t write(char* data, size_t length) {
+            return mraa_i2c_write(m_i2c, (const unsigned char *)data, (int) length);
         }
 
         /**
@@ -116,8 +116,8 @@ class I2c {
          * @param data Value to write to register
          * @return Result of operation
          */
-        mraa_result_t writeReg(const unsigned char reg, const unsigned char data) {
-            const unsigned char buf[2] = {reg, data};
+        mraa_result_t writeReg(char reg, char data) {
+            const unsigned char buf[2] = {(unsigned char) reg, (unsigned char) data};
             return mraa_i2c_write(m_i2c, buf, 2);
         }
 
@@ -127,7 +127,7 @@ class I2c {
          * @param data The byte to send on the bus
          * @return Result of operation
          */
-        mraa_result_t write(const unsigned char data) {
+        mraa_result_t write(char data) {
             return mraa_i2c_write_byte(m_i2c, data);
         }
     private:

api/mraa/spi.hpp

@@ -75,8 +75,8 @@ class Spi {
          * @param data the byte to send
          * @return data received on the miso line
          */
-        unsigned char write(uint8_t data) {
-            return (unsigned char) mraa_spi_write(m_spi, data);
+        unsigned char write(char data) {
+            return (unsigned char) mraa_spi_write(m_spi, (uint8_t) data);
         }
         /**
          * Write buffer of bytes to SPI device
@@ -85,8 +85,8 @@ class Spi {
          * @param length size of buffer to send
          * @return char* data received on the miso line. Same length as passed in
          */
-        unsigned char* write(uint8_t* data, int length) {
-            return (unsigned char*) mraa_spi_write_buf(m_spi, data, length);
+        unsigned char* write(char* data, size_t length) {
+            return (unsigned char*) mraa_spi_write_buf(m_spi, (uint8_t *) data, (int) length);
         }
         /**
          * Change the SPI lsb mode

examples/python/rgblcd.py

@@ -30,7 +30,8 @@ x = mraa.I2c(0)
 x.address(0x62)
 x.writeReg(0,0)
 x.writeReg(1,0)
-x.writeReg(0x08,0xAA)
-x.writeReg(0x04,255)
-x.writeReg(0x02,255)
 
+# Be careful that your i2c device can actually handle a 'batch' handling of
+# such data, this is not typical in arduino type devices
+s = "\x08\xAA\x04\x255\x02\x255"
+x.write(s)

src/mraa.i

@@ -1,4 +1,6 @@
 %include carrays.i
+%include stdint.i
+%array_class(char, mraaBuffer);
 
 #ifdef DOXYGEN
     %include common_doc.i
@@ -32,6 +34,8 @@
 %rename(getPlatform) mraa_get_platform_type;
 
 %typemap(in) uint8_t = char;
+%typemap(in) unsigned char* = char*;
+%apply (char *STRING, size_t LENGTH) { (char *data, size_t length) };
 
 %include "types.h"