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spi: omap2_mcspi PIO RX fix

PATCH In review David Brownell 2 participants 2 messages Jan 24, 2008 – Jan 25, 2008 1 message not in the archive SPI

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David Brownell

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PATCH 1/1 spi: omap2_mcspi PIO RX fix

From: Kalle Valo <[email protected]>

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]>
---
 drivers/spi/omap2_mcspi.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
drivers/spi/omap2_mcspi.c +3 -3
@@ -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);
 	}

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A message that is not in the archive (sent off-list or not yet received): 200801241340.25207.david-b-yBeKhBN/[email protected]

#2 lore raw
Quoted 8 lines

-----Original Message-----
From: David Brownell [mailto:david-b-yBeKhBN/[email protected]]
Sent: Friday, January 25, 2008 3:10 AM
To: Andrew Morton; spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: Kalle Valo; Girish
Subject: [patch 2.6.24-rc8] spi: omap2_mcspi PIO RX fix

Quoted 5 lines

From: Kalle Valo <[email protected]>

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

Yes, I had missed out this patch. Thanks dave.

Regards,
Girish

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