[PATCH 20/38] staging: comedi: das16: tidy up das16_ai_insn_read()

[H Hartley Sweeten]

Factor out the loop that waits for the ai conversion to complete.

Tidy up the function a bit.

Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
This also fixes a bug introduced by PATCH 05/38. The 'val' should be >> 4
not the 'data[n]'. If necessary I will rebase this series to fix the patch.

 drivers/staging/comedi/drivers/das16.c | 50 ++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/comedi/drivers/das16.c 
b/drivers/staging/comedi/drivers/das16.c
index f6d0f7e..a482bd5 100644
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -253,8 +253,6 @@ struct das16_board {
        unsigned int id;
 };
 
-#define DAS16_TIMEOUT 1000
-
 /* Period for timer interrupt in jiffies.  It's a function
  * to deal with possibility of dynamic HZ patches  */
 static inline int timer_period(void)
@@ -564,55 +562,61 @@ static void das16_reset(struct comedi_device *dev)
        outb(0, dev->iobase + DAS16_CNTR_CONTROL);
 }
 
+static int das16_ai_wait_for_conv(struct comedi_device *dev,
+                                 unsigned int timeout)
+{
+       unsigned int status;
+       int i;
+
+       for (i = 0; i < timeout; i++) {
+               status = inb(dev->iobase + DAS16_STATUS);
+               if (!(status & BUSY))
+                       return 0;
+       }
+       return -ETIME;
+}
+
 static int das16_ai_insn_read(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_insn *insn,
                              unsigned int *data)
 {
        const struct das16_board *board = comedi_board(dev);
-       int i, n;
-       int range;
-       int chan;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int range = CR_RANGE(insn->chanspec);
+       unsigned int val;
+       int ret;
+       int i;
 
        das16_ai_disable(dev);
 
        /* set multiplexer */
-       chan = CR_CHAN(insn->chanspec);
-       chan |= CR_CHAN(insn->chanspec) << 4;
-       outb(chan, dev->iobase + DAS16_MUX);
+       outb(chan | (chan << 4), dev->iobase + DAS16_MUX);
 
        /* set gain */
        if (board->ai_pg != das16_pg_none) {
-               range = CR_RANGE(insn->chanspec);
                outb((das16_gainlists[board->ai_pg])[range],
                     dev->iobase + DAS16_GAIN);
        }
 
-       for (n = 0; n < insn->n; n++) {
-               unsigned int val;
-
+       for (i = 0; i < insn->n; i++) {
                /* trigger conversion */
                outb_p(0, dev->iobase + DAS16_TRIG);
 
-               for (i = 0; i < DAS16_TIMEOUT; i++) {
-                       if (!(inb(dev->iobase + DAS16_STATUS) & BUSY))
-                               break;
-               }
-               if (i == DAS16_TIMEOUT) {
-                       printk("das16: timeout\n");
-                       return -ETIME;
-               }
+               ret = das16_ai_wait_for_conv(dev, 1000);
+               if (ret)
+                       return ret;
 
                val = inb(dev->iobase + DAS16_AI_MSB) << 8;
                val |= inb(dev->iobase + DAS16_AI_LSB);
                if (s->maxdata == 0x0fff)
-                       data[n] >>= 4;
+                       val >>= 4;
                val &= s->maxdata;
 
-               data[n] = val;
+               data[i] = val;
        }
 
-       return n;
+       return insn->n;
 }
 
 static int das16_di_insn_bits(struct comedi_device *dev,
-- 
1.8.3.2

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