SPISlave: Add explicit pinmap support

drivers/SPISlave.h

@@ -71,6 +71,14 @@ public:
      */
     SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);
 
+    /** Create a SPI slave connected to the specified pins.
+     *
+     *  @note Either mosi or miso can be specified as NC if not used.
+     *
+     *  @param explicit_pinmap reference to strucure which holds static pinmap.
+     */
+    SPISlave(const spi_pinmap_t &pinmap);
+
     /** Configure the data transmission format.
      *
      *  @param bits Number of bits per SPI frame (4 - 16).

drivers/source/SPISlave.cpp

@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 #include "drivers/SPISlave.h"
+#include "mbed_assert.h"
 
 #if DEVICE_SPISLAVE
 
@@ -31,6 +32,17 @@ SPISlave::SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel) :
     spi_frequency(&_spi, _hz);
 }
 
+SPISlave::SPISlave(const spi_pinmap_t &pinmap) :
+    _spi(),
+    _bits(8),
+    _mode(0),
+    _hz(1000000)
+{
+    spi_init_direct(&_spi, &pinmap);
+    spi_format(&_spi, _bits, _mode, 1);
+    spi_frequency(&_spi, _hz);
+}
+
 void SPISlave::format(int bits, int mode)
 {
     _bits = bits;