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authorDavid Fries <david@fries.net>2008-10-15 22:05:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 11:21:50 -0700
commite1c86d226daf95407d66246ced8fe087055acc6b (patch)
tree8c65de40bc97dfb267a652251660efd77608bff9 /drivers/w1
parent1f4ec2d7f6c4560a9d0c1abab2e8effe9ba93921 (diff)
downloadlinux-e1c86d226daf95407d66246ced8fe087055acc6b.tar.gz
W1: ds2490.c ds_write_bit, grouping error, disable readback
ds_write_bit doesn't read the input buffer, so add COMM_ICP and a comment
that it will no longer generate a read back data byte.  If there is an
extra data byte later on then it will cause an error and discard what data
was there.  Corrected operator ordering for ds_send_control.

Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/w1')
-rw-r--r--drivers/w1/masters/ds2490.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c
index 6b188e8008e4..6fabf584395f 100644
--- a/drivers/w1/masters/ds2490.c
+++ b/drivers/w1/masters/ds2490.c
@@ -525,7 +525,12 @@ static int ds_write_bit(struct ds_device *dev, u8 bit)
 	int err;
 	struct ds_status st;
 
-	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | (bit) ? COMM_D : 0, 0);
+	/* Set COMM_ICP to write without a readback.  Note, this will
+	 * produce one time slot, a down followed by an up with COMM_D
+	 * only determing the timing.
+	 */
+	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | COMM_ICP |
+		(bit ? COMM_D : 0), 0);
 	if (err)
 		return err;