[PATCH 3/3] staging: comedi: dt3000: remove unneeded variable

[PATCH 3/3] staging: comedi: dt3000: remove unneeded variable

[Chase Southwood]

Coccinelle (using scripts/coccinelle/tests/doublebitand.cocci) found this
assignment because 0 is or'd twice.  Upon inspection, I found that the
variable "mode" is only assigned once and used once, and thus can be
cleanly removed.  This patch plugs its value straight into writew() and
then removes the variable.

Signed-off-by: Chase Southwood <chase.southwood@gmail.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
---
It occurred to me while doing this that zero might be or'd twice to
indicate "no information" in order to maintain some three-part structure
used elsewhere.  If this is the case, I think that the variable could
still be removed and the "| 0 | 0" could be added to the writew().

 drivers/staging/comedi/drivers/dt3000.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/staging/comedi/drivers/dt3000.c b/drivers/staging/comedi/drivers/dt3000.c
index 56e21cc..176a7ee 100644
--- a/drivers/staging/comedi/drivers/dt3000.c
+++ b/drivers/staging/comedi/drivers/dt3000.c
@@ -488,7 +488,6 @@ static int dt3k_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	unsigned int chan, range, aref;
 	unsigned int divider;
 	unsigned int tscandiv;
-	unsigned int mode;
 
 	for (i = 0; i < cmd->chanlist_len; i++) {
 		chan = CR_CHAN(cmd->chanlist[i]);
@@ -513,8 +512,7 @@ static int dt3k_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 		writew((tscandiv & 0xffff), dev->mmio + DPR_Params(4));
 	}
 
-	mode = DT3000_AD_RETRIG_INTERNAL | 0 | 0;
-	writew(mode, dev->mmio + DPR_Params(5));
+	writew(DT3000_AD_RETRIG_INTERNAL, dev->mmio + DPR_Params(5));
 	writew(aref == AREF_DIFF, dev->mmio + DPR_Params(6));
 
 	writew(AI_FIFO_DEPTH / 2, dev->mmio + DPR_Params(7));
-- 
2.0.4

Re: [PATCH 3/3] staging: comedi: dt3000: remove unneeded variable

[Ian Abbott]

On 17/08/14 05:26, Chase Southwood wrote:
> Coccinelle (using scripts/coccinelle/tests/doublebitand.cocci) found this
> assignment because 0 is or'd twice.  Upon inspection, I found that the
> variable "mode" is only assigned once and used once, and thus can be
> cleanly removed.  This patch plugs its value straight into writew() and
> then removes the variable.
>
> Signed-off-by: Chase Southwood <chase.southwood@gmail.com>
> Cc: Ian Abbott <abbotti@mev.co.uk>
> Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
> ---
> It occurred to me while doing this that zero might be or'd twice to
> indicate "no information" in order to maintain some three-part structure
> used elsewhere.  If this is the case, I think that the variable could
> still be removed and the "| 0 | 0" could be added to the writew().
>
>   drivers/staging/comedi/drivers/dt3000.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)

This shouldn't be in the same series as the other two patches, but never 
mind.

Reviewed-by: Ian Abbott <abbotti@mev.co.uk>

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-