mpm: i2c: Add vector-based transfer function

This could lead to a less-restricted implementation for use in Python.

mpm/include/mpm/i2c/i2c_iface.hpp

@@ -9,6 +9,7 @@
 #include <boost/noncopyable.hpp>
 #include <memory>
 #include <string>
+#include <vector>
 
 namespace mpm { namespace i2c {
 
@@ -39,6 +40,17 @@ namespace mpm { namespace i2c {
          * \param rx_len Number of bytes to read
          */
         virtual int transfer(uint8_t *tx, size_t tx_len, uint8_t *rx, size_t rx_len) = 0;
+
+        /*!
+         * \param tx Buffer of data to send
+         * \param rx Buffer to hold read data
+         *
+         * All data in tx will be transmitted.
+         * The amount of data read will be determined by the number of elements
+         * in the rx vector. Those elements will be overwritten with the data.
+         * Use the resize() function for a new rx vector.
+         */
+        virtual int transfer(std::vector<uint8_t> *tx, std::vector<uint8_t> *rx) = 0;
     };
 
 }}; /* namespace mpm::i2c */

mpm/include/mpm/i2c/i2c_python.hpp

@@ -13,6 +13,17 @@ void export_i2c() {
     LIBMPM_BOOST_PREAMBLE("i2c")
 
     bp::def("make_i2cdev_regs_iface", &mpm::i2c::make_i2cdev_regs_iface);
+/*
+    bp::def("make_i2cdev", &mpm::i2c::i2c_iface::make_i2cdev);
 
+    int (mpm::i2c::i2c_iface::*transfer_vec)(std::vector<uint8_t>*,
+                                             std::vector<uint8_t>*) =
+        &mpm::i2c::i2c_iface::transfer;
+
+    bp::class_<mpm::i2c::i2c_iface, boost::noncopyable,
+               std::shared_ptr<mpm::i2c::i2c_iface> >("i2c_iface", bp::no_init)
+        .def("transfer", transfer_vec)
+    ;
+*/
 }
 

mpm/lib/i2c/i2cdev_iface.cpp

@@ -72,6 +72,24 @@ public:
         return ret;
     }
 
+    int transfer(std::vector<uint8_t> *tx, std::vector<uint8_t> *rx)
+    {
+        uint8_t *tx_data = NULL, *rx_data = NULL;
+        size_t tx_len = 0, rx_len = 0;
+
+        if (tx) {
+            tx_data = tx->data();
+            tx_len = tx->size();
+        }
+
+        if (rx) {
+            rx_data = rx->data();
+            rx_len = rx->size();
+        }
+        int ret = transfer(tx_data, tx_len, rx_data, rx_len);
+        return ret;
+    }
+
 private:
     int _fd;
     const uint16_t _addr;