From a96dc90250fdc31ff7fe59f752618773e2aa73df Mon Sep 17 00:00:00 2001
From: Brad Campbell <bradjc5@gmail.com>
Date: Tue, 18 Mar 2014 10:10:13 -0400
Subject: [PATCH] [SPI] Make SPI_FLUSH() more versatile

Currently the SPI driver in core/ sets `SPI_FLUSH()` to be a single read
of the spi RX buffer. This is fine for many microcontrollers, but newer
platforms like the CC2538 have a multi-byte FIFO for the RX buffer. In
that case, a single read is not guaranteed to flush the RX. This commit
allows `SPI_FLUSH()` to be platform dependent if needed, but doesn't
change for platforms where it works.
---
 core/dev/spi.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/core/dev/spi.h b/core/dev/spi.h
index a36be1ca7..1ccbe2bc0 100644
--- a/core/dev/spi.h
+++ b/core/dev/spi.h
@@ -82,10 +82,11 @@ void spi_init(void);
   } while(0)
 
 /* Flush the SPI read register */
+#ifndef SPI_FLUSH
 #define SPI_FLUSH() \
   do {              \
     SPI_RXBUF;      \
   } while(0);
-
+#endif
 
 #endif /* SPI_H_ */