Added polled API to the STM32 SPI driver.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@2303 35acf78f-673a-0410-8e92-d51de3d6d3f4

os/hal/platforms/STM32/spi_lld.c

@@ -466,6 +466,26 @@ void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
   dma_start(spip);
 }
 
+/**
+ * @brief   Exchanges one frame using a polled wait.
+ * @details This synchronous function exchanges one frame using a polled
+ *          synchronization method. This function is useful when exchanging
+ *          small amount of data on high speed channels, usually in this
+ *          situation is much more efficient just wait for completion using
+ *          polling than suspending the thread waiting for an interrupt.
+ *
+ * @param[in] spip      pointer to the @p SPIDriver object
+ * @param[in] frame     the data frame to send over the SPI bus
+ * @return              The received data frame from the SPI bus.
+ */
+uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
+
+  spip->spd_spi->DR = frame;
+  while ((spip->spd_spi->SR & SPI_SR_RXNE) == 0)
+    ;
+  return spip->spd_spi->DR;
+}
+
 #endif /* CH_HAL_USE_SPI */
 
 /** @} */

os/hal/platforms/STM32/spi_lld.h

@@ -282,6 +282,7 @@ extern "C" {
                         const void *txbuf, void *rxbuf);
   void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf);
   void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf);
+  uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame);
 #ifdef __cplusplus
 }
 #endif