From a884e58e2cea877f804cb643d4d1e0909bd1fa49 Mon Sep 17 00:00:00 2001
From: gdisirio <gdisirio@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Sat, 30 Oct 2010 11:18:28 +0000
Subject: Added a polled exchange function to the SPI driver model, implemented
 on LPCxxxx SPI drivers.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@2302 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/hal/platforms/LPC11xx/spi_lld.c | 28 +++++++++++++++++++++++-----
 os/hal/platforms/LPC11xx/spi_lld.h |  1 +
 2 files changed, 24 insertions(+), 5 deletions(-)

(limited to 'os/hal/platforms/LPC11xx')

diff --git a/os/hal/platforms/LPC11xx/spi_lld.c b/os/hal/platforms/LPC11xx/spi_lld.c
index becf691a3..8b0081b5e 100644
--- a/os/hal/platforms/LPC11xx/spi_lld.c
+++ b/os/hal/platforms/LPC11xx/spi_lld.c
@@ -234,13 +234,15 @@ void spi_lld_start(SPIDriver *spip) {
 void spi_lld_stop(SPIDriver *spip) {
 
   if (spip->spd_state != SPI_STOP) {
+    spip->spd_ssp->CR1  = 0;
+    spip->spd_ssp->CR0  = 0;
+    spip->spd_ssp->CPSR = 0;
 #if LPC11xx_SPI_USE_SSP0
     if (&SPID1 == spip) {
       LPC_SYSCON->PRESETCTRL &= ~1;
       LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 11);
       LPC_SYSCON->SSP0CLKDIV = 0;
       NVICDisableVector(SSP0_IRQn);
-      return;
     }
 #endif
 #if LPC11xx_SPI_USE_SSP1
@@ -249,12 +251,8 @@ void spi_lld_stop(SPIDriver *spip) {
       LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 18);
       LPC_SYSCON->SSP1CLKDIV = 0;
       NVICDisableVector(SSP1_IRQn);
-      return;
     }
 #endif
-    spip->spd_ssp->CR1  = 0;
-    spip->spd_ssp->CR0  = 0;
-    spip->spd_ssp->CPSR = 0;
   }
 }
 
@@ -372,6 +370,26 @@ void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
   spip->spd_ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
 }
 
+/**
+ * @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_ssp->DR = (uint32_t)frame;
+  while ((spip->spd_ssp->SR & SR_RNE) == 0)
+    ;
+  return (uint16_t)spip->spd_ssp->DR;
+}
+
 #endif /* CH_HAL_USE_SPI */
 
 /** @} */
diff --git a/os/hal/platforms/LPC11xx/spi_lld.h b/os/hal/platforms/LPC11xx/spi_lld.h
index 021099097..b3f38056f 100644
--- a/os/hal/platforms/LPC11xx/spi_lld.h
+++ b/os/hal/platforms/LPC11xx/spi_lld.h
@@ -334,6 +334,7 @@ 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
-- 
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