From: David Fries 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 Signed-off-by: Evgeniy Polyakov Signed-off-by: Andrew Morton --- drivers/w1/masters/ds2490.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff -puN drivers/w1/masters/ds2490.c~w1-ds2490c-ds_write_bit-grouping-error-disable-readback drivers/w1/masters/ds2490.c --- a/drivers/w1/masters/ds2490.c~w1-ds2490c-ds_write_bit-grouping-error-disable-readback +++ a/drivers/w1/masters/ds2490.c @@ -525,7 +525,12 @@ static int ds_write_bit(struct ds_device 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; _