From: Kalle Valo <kalle.valo@nokia.com>
Date: Fri, 11 Jan 2008 17:28:51 +0000 (+0200)
Subject: omap2_mcspi: fix PIO RX_ONLY transfer
X-Git-Tag: v2.6.24-omap1~63
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=2ae71b94269fa117f637ba01f1f26d978ac2f60a;p=linux-2.6-omap-h63xx.git

omap2_mcspi: fix PIO RX_ONLY transfer

Before transmission of the last word in PIO RX_ONLY mode rx+tx mode
is enabled:

	/* prevent last RX_ONLY read from triggering
	 * more word i/o: switch to rx+tx
	 */
	if (c == 0 && tx == NULL)
		mcspi_write_cs_reg(spi,
				OMAP2_MCSPI_CHCONF0, l);

But because c is decremented after the test, c will never be zero and
rx+tx will not be enabled. This breaks RX_ONLY mode PIO transfers.

Fix it by decrementing c already in the beginning of the loop.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---

diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index 3cdab131c4a..ea61724ae22 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -350,6 +350,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 		tx = xfer->tx_buf;
 
 		do {
+			c -= 1;
 			if (tx != NULL) {
 				if (mcspi_wait_for_reg_bit(chstat_reg,
 						OMAP2_MCSPI_CHSTAT_TXS) < 0) {
@@ -380,7 +381,6 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 						word_len, *(rx - 1));
 #endif
 			}
-			c -= 1;
 		} while (c);
 	} else if (word_len <= 16) {
 		u16		*rx;
@@ -389,6 +389,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 		rx = xfer->rx_buf;
 		tx = xfer->tx_buf;
 		do {
+			c -= 2;
 			if (tx != NULL) {
 				if (mcspi_wait_for_reg_bit(chstat_reg,
 						OMAP2_MCSPI_CHSTAT_TXS) < 0) {
@@ -419,7 +420,6 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 						word_len, *(rx - 1));
 #endif
 			}
-			c -= 2;
 		} while (c);
 	} else if (word_len <= 32) {
 		u32		*rx;
@@ -428,6 +428,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 		rx = xfer->rx_buf;
 		tx = xfer->tx_buf;
 		do {
+			c -= 4;
 			if (tx != NULL) {
 				if (mcspi_wait_for_reg_bit(chstat_reg,
 						OMAP2_MCSPI_CHSTAT_TXS) < 0) {
@@ -458,7 +459,6 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 						word_len, *(rx - 1));
 #endif
 			}
-			c -= 4;
 		} while (c);
 	}