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authorLuotao Fu <l.fu@pengutronix.de>2008-07-28 15:46:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-28 16:30:21 -0700
commit9a7867e1b34c3575e7e76a05c0c54c6edbdae2a4 (patch)
treefb4df3c93ed711ae22dcd82320133af86bf42568 /drivers/spi
parent78a34ae29bf1c9df62a5bd0f0798b6c62a54d520 (diff)
mpc52xx_psc_spi: fix block transfer
The block transfer routine in the mpc52xx psc spi driver misinterpret the datasheet. According to the processor datasheet the chipselect is held as long as the EOF is not written. Theoretically blocks of any sizes can be transferred in this way. The old routine however writes an EOF after every word, which has the size of size_of_word. This makes the transfer slow. Also fixed some duplicate code. Signed-off-by: Luotao Fu <l.fu@pengutronix.de> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/mpc52xx_psc_spi.c22
1 files changed, 7 insertions, 15 deletions
diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
index 604e5f0a2d9..25eda71f4bf 100644
--- a/drivers/spi/mpc52xx_psc_spi.c
+++ b/drivers/spi/mpc52xx_psc_spi.c
@@ -148,7 +148,6 @@ static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
unsigned rfalarm;
unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
unsigned recv_at_once;
- unsigned bpw = mps->bits_per_word / 8;
if (!t->tx_buf && !t->rx_buf && t->len)
return -EINVAL;
@@ -164,22 +163,15 @@ static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
}
dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
- if (tx_buf) {
- for (; send_at_once; sb++, send_at_once--) {
- /* set EOF flag */
- if (mps->bits_per_word
- && (sb + 1) % bpw == 0)
- out_8(&psc->ircr2, 0x01);
+ for (; send_at_once; sb++, send_at_once--) {
+ /* set EOF flag before the last word is sent */
+ if (send_at_once == 1)
+ out_8(&psc->ircr2, 0x01);
+
+ if (tx_buf)
out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
- }
- } else {
- for (; send_at_once; sb++, send_at_once--) {
- /* set EOF flag */
- if (mps->bits_per_word
- && ((sb + 1) % bpw) == 0)
- out_8(&psc->ircr2, 0x01);
+ else
out_8(&psc->mpc52xx_psc_buffer_8, 0);
- }
}