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authorAtsushi Nemoto <anemo@mba.ocn.ne.jp>2008-04-28 02:14:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-28 08:58:31 -0700
commit06719814780da741e7acf587367a86c3965c03a2 (patch)
treea6d8aabc4b3068c3679630f318a1706044c195b1 /drivers
parentb687d2a8f8d46921ac5e80bf77967688afce68e2 (diff)
downloadop-kernel-dev-06719814780da741e7acf587367a86c3965c03a2.zip
op-kernel-dev-06719814780da741e7acf587367a86c3965c03a2.tar.gz
atmel_spi: support zero length transfer
A spi transfer with zero length is not invalid. For example, such transfer (len == 0 && delay_usecs != 0) can be used to achieve delay before first CLK edge after chipselect assertion. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/spi/atmel_spi.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 1749a27..02c8e30 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -616,7 +616,7 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
return -ESHUTDOWN;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
- if (!(xfer->tx_buf || xfer->rx_buf)) {
+ if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
dev_dbg(&spi->dev, "missing rx or tx buf\n");
return -EINVAL;
}
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