This is a note to let you know that I've just added the patch titled
staging: comedi: ni_daq_700: add mux settling delay
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From ffed54dced86723f352323f15789d9ad6bee25e1 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Mon, 19 May 2014 11:29:04 +0100
Subject: staging: comedi: ni_daq_700: add mux settling delay
I got a patch from the original author, Fred Brooks, to add a small
settling delay after setting the AI channel multiplexor. The lack of
delay resulted in unstable or scrambled data on faster processors.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
Reported-by: Fred Brooks <nsaspook@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 3.7.x - 3.15.x
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/ni_daq_700.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/comedi/drivers/ni_daq_700.c b/drivers/staging/comedi/drivers/ni_daq_700.c
index 171a71d20c88..728bf7f14f7b 100644
--- a/drivers/staging/comedi/drivers/ni_daq_700.c
+++ b/drivers/staging/comedi/drivers/ni_daq_700.c
@@ -139,6 +139,8 @@ static int daq700_ai_rinsn(struct comedi_device *dev,
/* write channel to multiplexer */
/* set mask scan bit high to disable scanning */
outb(chan | 0x80, dev->iobase + CMD_R1);
+ /* mux needs 2us to really settle [Fred Brooks]. */
+ udelay(2);
/* convert n samples */
for (n = 0; n < insn->n; n++) {
--
2.0.0.rc3.2.g998f840
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