Introduce a helper function to set the analog input channel scan and range
control registers. Use the new helper in the analog input (*insn_read) and
(*do_cmd) functions.
The extra sanity checks in the (*do_cmd) are not necessary. The cmd->chanlist
will always be valid and the (*do_cmdtest) validates the channel list in
Step 5.
Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/dmm32at.c | 53 ++++++++++++--------------------
1 file changed, 20 insertions(+), 33 deletions(-)
diff --git a/drivers/staging/comedi/drivers/dmm32at.c
b/drivers/staging/comedi/drivers/dmm32at.c
index 6413f60..dc222d1 100644
--- a/drivers/staging/comedi/drivers/dmm32at.c
+++ b/drivers/staging/comedi/drivers/dmm32at.c
@@ -154,6 +154,24 @@ struct dmm32at_private {
unsigned char dio_config;
};
+static void dmm32at_ai_set_chanspec(struct comedi_device *dev,
+ struct comedi_subdevice *s,
+ unsigned int chanspec, int nchan)
+{
+ unsigned int chan = CR_CHAN(chanspec);
+ unsigned int range = CR_RANGE(chanspec);
+ unsigned int last_chan = (chan + nchan - 1) % s->n_chan;
+
+ outb(DMM32AT_FIFORESET, dev->iobase + DMM32AT_FIFOCNTRL);
+
+ if (nchan > 1)
+ outb(DMM32AT_SCANENABLE, dev->iobase + DMM32AT_FIFOCNTRL);
+
+ outb(chan, dev->iobase + DMM32AT_AILOW);
+ outb(last_chan, dev->iobase + DMM32AT_AIHIGH);
+ outb(dmm32at_rangebits[range], dev->iobase + DMM32AT_AICONF);
+}
+
static unsigned int dmm32at_ai_get_sample(struct comedi_device *dev,
struct comedi_subdevice *s)
{
@@ -184,18 +202,10 @@ static int dmm32at_ai_insn_read(struct comedi_device *dev,
struct comedi_insn *insn,
unsigned int *data)
{
- unsigned int chan = CR_CHAN(insn->chanspec);
- unsigned int range = CR_RANGE(insn->chanspec);
int ret;
int i;
- /* zero scan and fifo control and reset fifo */
- outb(DMM32AT_FIFORESET, dev->iobase + DMM32AT_FIFOCNTRL);
-
- /* set the channel and range */
- outb(chan, dev->iobase + DMM32AT_AILOW);
- outb(chan, dev->iobase + DMM32AT_AIHIGH);
- outb(dmm32at_rangebits[range], dev->iobase + DMM32AT_AICONF);
+ dmm32at_ai_set_chanspec(dev, s, insn->chanspec, 1);
/* wait for circuit to settle */
ret = comedi_timeout(dev, s, insn, dmm32at_ai_status, DMM32AT_AIRBACK);
@@ -347,32 +357,9 @@ static void dmm32at_setaitimer(struct comedi_device *dev,
unsigned int nansec)
static int dmm32at_ai_cmd(struct comedi_device *dev, struct comedi_subdevice
*s)
{
struct comedi_cmd *cmd = &s->async->cmd;
- int range;
- unsigned char chanlo, chanhi;
int ret;
- if (!cmd->chanlist)
- return -EINVAL;
-
- /* get the channel list and range */
- chanlo = CR_CHAN(cmd->chanlist[0]) & (s->n_chan - 1);
- chanhi = chanlo + cmd->chanlist_len - 1;
- if (chanhi >= s->n_chan)
- return -EINVAL;
- range = CR_RANGE(cmd->chanlist[0]);
-
- /* reset fifo */
- outb(DMM32AT_FIFORESET, dev->iobase + DMM32AT_FIFOCNTRL);
-
- /* set scan enable */
- outb(DMM32AT_SCANENABLE, dev->iobase + DMM32AT_FIFOCNTRL);
-
- /* write the ai channel range regs */
- outb(chanlo, dev->iobase + DMM32AT_AILOW);
- outb(chanhi, dev->iobase + DMM32AT_AIHIGH);
-
- /* set the range bits */
- outb(dmm32at_rangebits[range], dev->iobase + DMM32AT_AICONF);
+ dmm32at_ai_set_chanspec(dev, s, cmd->chanlist[0], cmd->chanlist_len);
/* reset the interrupt just in case */
outb(DMM32AT_INTRESET, dev->iobase + DMM32AT_CNTRL);
--
2.0.3
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