i2c.hpp: Add C++ wrapper around I2c

* maa_i2c_context bcomes an opaque pointer
* C++ wrapper class I2c created
* swig now uses C++ wrapper I2c to generate API

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

api/aio.hpp

@@ -23,6 +23,7 @@
  */
 
 #pragma once
+
 /** @file
  *
  * This file defines the aio C++ interface for libmaa

api/i2c.h

@@ -42,29 +42,23 @@ extern "C" {
 #include "gpio.h"
 
 /**
- * A structure representing an i2c device /dev/i2c-*
+ * Opaque pointer definition to the internal struct _i2c
  */
-typedef struct {
-    /*@{*/
-    int hz; /**< frequency of communication */
-    int fh; /**< the file handle to the /dev/i2c-* device */
-    int addr; /**< the address of the i2c slave */
-    /*@}*/
-} maa_i2c_context;
+typedef struct _i2c* maa_i2c_context;
 
 /** Initialise i2c context, using board defintions
  *
  * @param bus i2c bus to use
  * @return maa_i2c_context i2c context ready for other calls.
  */
-maa_i2c_context* maa_i2c_init(int bus);
+maa_i2c_context maa_i2c_init(int bus);
 
 /** Initialise i2c context, passing in spi bus to use.
  *
  * @param bus The i2c bus to use i.e. /dev/i2c-2 would be "2"
  * @return maa_i2c_context i2c context ready for other calls.
  */
-maa_i2c_context* maa_i2c_init_raw(unsigned int bus);
+maa_i2c_context maa_i2c_init_raw(unsigned int bus);
 
 /** Sets the frequency of the i2c context
  *
@@ -73,7 +67,7 @@ maa_i2c_context* maa_i2c_init_raw(unsigned int bus);
  *
  *  @return maa_result_t the maa result.
  */
-maa_result_t maa_i2c_frequency(maa_i2c_context* dev, int hz);
+maa_result_t maa_i2c_frequency(maa_i2c_context dev, int hz);
 
 /** Read from an i2c context
  *
@@ -83,7 +77,7 @@ maa_result_t maa_i2c_frequency(maa_i2c_context* dev, int hz);
  *
  *  @return maa_result_t the maa result.
  */
-maa_result_t maa_i2c_read(maa_i2c_context* dev, char *data, int length);
+maa_result_t maa_i2c_read(maa_i2c_context dev, const char *data, int length);
 
 /** Read a single byte from the i2c context
  *
@@ -91,7 +85,7 @@ maa_result_t maa_i2c_read(maa_i2c_context* dev, char *data, int length);
  *
  *  @return byte the result of the read or -1 if failed.
  */
-int maa_i2c_read_byte(maa_i2c_context* dev);
+int maa_i2c_read_byte(maa_i2c_context dev);
 
 /** Write to an i2c context
  *
@@ -101,7 +95,7 @@ int maa_i2c_read_byte(maa_i2c_context* dev);
  *
  *  @return maa_result_t the maa result.
  */
-maa_result_t maa_i2c_write(maa_i2c_context* dev, const char *data, int length);
+maa_result_t maa_i2c_write(maa_i2c_context dev, char *data, int length);
 
 /** Write a single byte to an i2c context
  *
@@ -110,7 +104,7 @@ maa_result_t maa_i2c_write(maa_i2c_context* dev, const char *data, int length);
  *
  *  @return maa_result_t the maa result.
  */
-maa_result_t maa_i2c_write_byte(maa_i2c_context* dev, int data);
+maa_result_t maa_i2c_write_byte(maa_i2c_context dev, int data);
 
 /** Sets the i2c context address.
  *
@@ -121,7 +115,7 @@ maa_result_t maa_i2c_write_byte(maa_i2c_context* dev, int data);
  *
  *  @return maa_result_t the maa result.
  */
-maa_result_t maa_i2c_address(maa_i2c_context* dev, int address);
+maa_result_t maa_i2c_address(maa_i2c_context dev, int address);
 
 /** De-inits an maa_i2c_context device
  *
@@ -129,7 +123,7 @@ maa_result_t maa_i2c_address(maa_i2c_context* dev, int address);
  *
  *  @return maa_result_t the maa result.
  */
-maa_result_t maa_i2c_stop(maa_i2c_context* dev);
+maa_result_t maa_i2c_stop(maa_i2c_context dev);
 
 #ifdef __cplusplus
 }

api/i2c.hpp

@@ -0,0 +1,70 @@
+/*
+ * Author: Brendan Le Foll <brendan.le.foll@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+
+/** @file
+ *
+ * This file defines the i2c C++ interface for libmaa
+ *
+ */
+
+#include "i2c.h"
+
+namespace maa {
+
+class I2c {
+    public:
+        I2c(int bus, bool raw=false) {
+            if (raw)
+                m_i2c = maa_i2c_init_raw(bus);
+            else
+                m_i2c = maa_i2c_init(bus);
+        }
+        ~I2c() {
+            maa_i2c_stop(m_i2c);
+        }
+        maa_result_t frequency(int hz) {
+            return maa_i2c_frequency(m_i2c, hz);
+        }
+        maa_result_t address(int address) {
+            return maa_i2c_address(m_i2c, address);
+        }
+        int read_byte() {
+            return maa_i2c_read_byte(m_i2c);
+        }
+        maa_result_t read(const char *data, int length) {
+            return maa_i2c_read(m_i2c, data, length);
+        }
+        maa_result_t write(char *data, int length) {
+            return maa_i2c_write(m_i2c, data, length);
+        }
+        maa_result_t write_byte(int data) {
+            return maa_i2c_write_byte(m_i2c, data);
+        }
+    private:
+        maa_i2c_context m_i2c;
+};
+
+}

examples/i2c_HMC5883L.c

@@ -83,7 +83,7 @@ main(int argc, char **argv)
     int16_t x = 0, y = 0, z = 0;
     char rx_tx_buf[MAX_BUFFER_LENGTH];
 
-    maa_i2c_context *i2c;
+    maa_i2c_context i2c;
     i2c = maa_i2c_init(0);
 
     maa_i2c_address(i2c, HMC5883L_I2C_ADDR);

src/CMakeLists.txt

@@ -7,6 +7,7 @@ set (maa_LIB_HEADERS
   ${PROJECT_SOURCE_DIR}/api/maa.h
   ${PROJECT_SOURCE_DIR}/api/gpio.h
   ${PROJECT_SOURCE_DIR}/api/i2c.h
+  ${PROJECT_SOURCE_DIR}/api/i2c.pp
   ${PROJECT_SOURCE_DIR}/api/pwm.h
   ${PROJECT_SOURCE_DIR}/api/spi.h
   ${PROJECT_SOURCE_DIR}/api/aio.h

src/i2c/i2c.c

@@ -25,7 +25,15 @@
 #include "i2c.h"
 #include "smbus.h"
 
-maa_i2c_context*
+struct _i2c {
+    /*@{*/
+    int hz; /**< frequency of communication */
+    int fh; /**< the file handle to the /dev/i2c-* device */
+    int addr; /**< the address of the i2c slave */
+    /*@}*/
+}; 
+
+maa_i2c_context
 maa_i2c_init(int bus)
 {
     int checked_pin = maa_check_i2c(bus);
@@ -46,10 +54,10 @@ maa_i2c_init(int bus)
     return maa_i2c_init_raw((unsigned int) checked_pin);
 }
 
-maa_i2c_context*
+maa_i2c_context
 maa_i2c_init_raw(unsigned int bus)
 {
-    maa_i2c_context* dev = (maa_i2c_context*) malloc(sizeof(maa_i2c_context));
+    maa_i2c_context dev = (maa_i2c_context) malloc(sizeof(struct _i2c));
     if (dev == NULL)
         return NULL;
 
@@ -62,7 +70,7 @@ maa_i2c_init_raw(unsigned int bus)
 }
 
 maa_result_t
-maa_i2c_frequency(maa_i2c_context* dev, int hz)
+maa_i2c_frequency(maa_i2c_context dev, int hz)
 {
     dev->hz = hz;
 
@@ -70,7 +78,7 @@ maa_i2c_frequency(maa_i2c_context* dev, int hz)
 }
 
 maa_result_t
-maa_i2c_read(maa_i2c_context* dev, char *data, int length)
+maa_i2c_read(maa_i2c_context dev, const char *data, int length)
 {
     // this is the read(3) syscall not maa_i2c_read()
     if (read(dev->fh, data, length) == length) {
@@ -80,7 +88,7 @@ maa_i2c_read(maa_i2c_context* dev, char *data, int length)
 }
 
 int
-maa_i2c_read_byte(maa_i2c_context* dev)
+maa_i2c_read_byte(maa_i2c_context dev)
 {
     int byte;
     byte = i2c_smbus_read_byte(dev->fh);
@@ -91,7 +99,7 @@ maa_i2c_read_byte(maa_i2c_context* dev)
 }
 
 maa_result_t
-maa_i2c_write(maa_i2c_context* dev, const char* data, int length)
+maa_i2c_write(maa_i2c_context dev, char* data, int length)
 {
     if (i2c_smbus_write_i2c_block_data(dev->fh, data[0], length-1, (uint8_t*) data+1) < 0) {
         fprintf(stderr, "Failed to write to i2c\n");
@@ -101,7 +109,7 @@ maa_i2c_write(maa_i2c_context* dev, const char* data, int length)
 }
 
 maa_result_t
-maa_i2c_write_byte(maa_i2c_context* dev, int data)
+maa_i2c_write_byte(maa_i2c_context dev, int data)
 {
     if (i2c_smbus_write_byte(dev->fh, data) < 0) {
         fprintf(stderr, "Failed to write to i2c\n");
@@ -111,7 +119,7 @@ maa_i2c_write_byte(maa_i2c_context* dev, int data)
 }
 
 maa_result_t
-maa_i2c_address(maa_i2c_context* dev, int addr)
+maa_i2c_address(maa_i2c_context dev, int addr)
 {
     dev->addr = addr;
     if (ioctl(dev->fh, I2C_SLAVE_FORCE, addr) < 0) {
@@ -122,7 +130,7 @@ maa_i2c_address(maa_i2c_context* dev, int addr)
 }
 
 maa_result_t
-maa_i2c_stop(maa_i2c_context* dev)
+maa_i2c_stop(maa_i2c_context dev)
 {
     free(dev);
     return MAA_SUCCESS;

src/maa.i

@@ -2,7 +2,7 @@
     #include "maa.h"
     #include "gpio.h"
     #include "pwm.h"
-    #include "i2c.h"
+    #include "i2c.hpp"
     #include "spi.h"
     #include "aio.hpp"
 %}
@@ -126,48 +126,7 @@ typedef struct {
 
 #### i2c ####
 
-%nodefault maa_i2c_context;
-%rename(I2c) maa_i2c_context;
-
-%ignore fh;
-typedef struct {
-    /*@{*/
-    int hz; /**< frequency of communication */
-    int fh; /**< the file handle to the /dev/i2c-* device */
-    int addr; /**< the address of the i2c slave */
-    /*@}*/
-} maa_i2c_context;
-
-%nodefault maa_i2c_context;
-%extend maa_i2c_context {
-  maa_i2c_context()
-  {
-    return maa_i2c_init(0);
-  }
-  ~maa_i2c_context()
-  {
-  }
-  int frequency(int hz)
-  {
-    return maa_i2c_frequency($self, hz);
-  }
-  int read(char *data, int length)
-  {
-    return maa_i2c_read($self, data, length);
-  }
-  int read()
-  {
-    return maa_i2c_read_byte($self);
-  }
-  int write(char *data, int length)
-  {
-    return maa_i2c_write($self, data, length);
-  }
-  int write(int data)
-  {
-    return maa_i2c_write_byte($self, data);
-  }
-}
+%include "i2c.hpp"
 
 #### PWM ####