spi: omap2_mcspi PIO RX fix

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 in the beginning of the various I/O loops. Signed-off-by: Kalle Valo <[email protected]> Signed-off-by: David Brownell <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mna · Jan 24, 2008 · feed9ba · feed9ba
1 parent dbcc2ec
commit feed9ba
Showing 1 changed file with 3 additions and 3 deletions.
diff --git 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);
 	}