[U-Boot] [PATCH] spi: oc_tiny_spi: Refactor to simplify spi_xfer implementation

[Axel Lin <axel.lin@ingics.com>]

Currently we have similar code for (txp && rxp), (txp && !rxp), (!rxp & txp),
and (!txp && !rxp) cases. This patch refactors the code a bit to avoid
duplicate similar code.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
Hi Thomas,
This path is similar to the patch I sent for spi-oc-tiny.c linux driver.
I'd appreciate if you can review and test this patch.
Regards,
Axel
 drivers/spi/oc_tiny_spi.c | 85 ++++++-----------------------------------------
 1 file changed, 11 insertions(+), 74 deletions(-)

diff --git a/drivers/spi/oc_tiny_spi.c b/drivers/spi/oc_tiny_spi.c
index 4de5d00..a8c1dfd 100644
--- a/drivers/spi/oc_tiny_spi.c
+++ b/drivers/spi/oc_tiny_spi.c
@@ -158,85 +158,22 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 		spi_cs_activate(slave);
 
 	/* we need to tighten the transfer loop */
-	if (txp && rxp) {
-		writeb(*txp++, &regs->txdata);
-		if (bytes > 1) {
-			writeb(*txp++, &regs->txdata);
-			for (i = 2; i < bytes; i++) {
-				u8 rx, tx = *txp++;
-				while (!(readb(&regs->status) &
-					 TINY_SPI_STATUS_TXR))
+	writeb(txp ? *txp++ : CONFIG_TINY_SPI_IDLE_VAL, &regs->txdata);
+	for (i = 1; i < bytes; i++) {
+		writeb(txp ? *txp++ : CONFIG_TINY_SPI_IDLE_VAL, &regs->txdata);
+
+		if (rxp || (i != bytes - 1)) {
+			while (!(readb(&regs->status) & TINY_SPI_STATUS_TXR))
 					;
-				rx = readb(&regs->txdata);
-				writeb(tx, &regs->txdata);
-				*rxp++ = rx;
-			}
-			while (!(readb(&regs->status) &
-				 TINY_SPI_STATUS_TXR))
-				;
-			*rxp++ = readb(&regs->txdata);
 		}
-		while (!(readb(&regs->status) &
-			 TINY_SPI_STATUS_TXE))
-			;
-		*rxp++ = readb(&regs->rxdata);
-	} else if (rxp) {
-		writeb(CONFIG_TINY_SPI_IDLE_VAL, &regs->txdata);
-		if (bytes > 1) {
-			writeb(CONFIG_TINY_SPI_IDLE_VAL,
-			       &regs->txdata);
-			for (i = 2; i < bytes; i++) {
-				u8 rx;
-				while (!(readb(&regs->status) &
-					 TINY_SPI_STATUS_TXR))
-					;
-				rx = readb(&regs->txdata);
-				writeb(CONFIG_TINY_SPI_IDLE_VAL,
-				       &regs->txdata);
-				*rxp++ = rx;
-			}
-			while (!(readb(&regs->status) &
-				 TINY_SPI_STATUS_TXR))
-				;
+
+		if (rxp)
 			*rxp++ = readb(&regs->txdata);
-		}
-		while (!(readb(&regs->status) &
-			 TINY_SPI_STATUS_TXE))
+	}
+	while (!(readb(&regs->status) & TINY_SPI_STATUS_TXE))
 			;
+	if (rxp)
 		*rxp++ = readb(&regs->rxdata);
-	} else if (txp) {
-		writeb(*txp++, &regs->txdata);
-		if (bytes > 1) {
-			writeb(*txp++, &regs->txdata);
-			for (i = 2; i < bytes; i++) {
-				u8 tx = *txp++;
-				while (!(readb(&regs->status) &
-					 TINY_SPI_STATUS_TXR))
-					;
-				writeb(tx, &regs->txdata);
-			}
-		}
-		while (!(readb(&regs->status) &
-			 TINY_SPI_STATUS_TXE))
-			;
-	} else {
-		writeb(CONFIG_TINY_SPI_IDLE_VAL, &regs->txdata);
-		if (bytes > 1) {
-			writeb(CONFIG_TINY_SPI_IDLE_VAL,
-			       &regs->txdata);
-			for (i = 2; i < bytes; i++) {
-				while (!(readb(&regs->status) &
-					 TINY_SPI_STATUS_TXR))
-					;
-				writeb(CONFIG_TINY_SPI_IDLE_VAL,
-				       &regs->txdata);
-			}
-		}
-		while (!(readb(&regs->status) &
-			 TINY_SPI_STATUS_TXE))
-			;
-	}
-
  done:
 	if (flags & SPI_XFER_END)
 		spi_cs_deactivate(slave);
-- 
1.8.1.2