staging: comedi: adv_pci1710: tidy up pci171x_ai_check_chanlist()

Tidy up this function to clarify what the chanlist is being checked for.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
index 765b1f00255bc7b40be90fa85e5a10400bfa0b87..da1309b80691f732a27a35ee093e1a5d4eb3f6a0 100644 (file)
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -326,60 +326,61 @@ static const unsigned int muxonechan[] = {
        0x1818, 0x1919, 0x1a1a, 0x1b1b, 0x1c1c, 0x1d1d, 0x1e1e, 0x1f1f
 };
 
-/*
-==============================================================================
- Check if channel list from user is built correctly
- If it's ok, then program scan/gain logic.
- This works for all cards.
-*/
 static int pci171x_ai_check_chanlist(struct comedi_device *dev,
                                     struct comedi_subdevice *s,
                                     struct comedi_cmd *cmd)
 {
+       unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
+       unsigned int last_aref = CR_AREF(cmd->chanlist[0]);
+       unsigned int next_chan = (chan0 + 1) % s->n_chan;
        unsigned int chansegment[32];
-       unsigned int i, nowmustbechan, seglen, segpos;
-       unsigned int *chanlist = cmd->chanlist;
-       unsigned int n_chan = cmd->chanlist_len;
-
-       /* correct channel and range number check itself comedi/range.c */
-       if (n_chan < 1) {
-               comedi_error(dev, "range/channel list is empty!");
-               return 0;
-       }
+       unsigned int seglen;
+       int i;
 
-       if (n_chan == 1)
+       if (cmd->chanlist_len == 1)
                return 1; /* seglen=1 */
 
-       chansegment[0] = chanlist[0]; /*  first channel is every time ok */
-       for (i = 1, seglen = 1; i < n_chan; i++, seglen++) {
-               if (chanlist[0] == chanlist[i])
+       /* first channel is always ok */
+       chansegment[0] = cmd->chanlist[0];
+
+       for (i = 1; i < cmd->chanlist_len; i++) {
+               unsigned int chan = CR_CHAN(cmd->chanlist[i]);
+               unsigned int aref = CR_AREF(cmd->chanlist[i]);
+
+               if (cmd->chanlist[0] == cmd->chanlist[i])
                        break;  /*  we detected a loop, stop */
-               if ((CR_CHAN(chanlist[i]) & 1) &&
-                   (CR_AREF(chanlist[i]) == AREF_DIFF)) {
-                       comedi_error(dev, "Odd channel cannot be differential input!\n");
+
+               if (aref == AREF_DIFF && (chan & 1)) {
+                       dev_err(dev->class_dev,
+                               "Odd channel cannot be differential input!\n");
                        return 0;
                }
-               nowmustbechan = (CR_CHAN(chansegment[i - 1]) + 1) % s->n_chan;
-               if (CR_AREF(chansegment[i - 1]) == AREF_DIFF)
-                       nowmustbechan = (nowmustbechan + 1) % s->n_chan;
-               if (nowmustbechan != CR_CHAN(chanlist[i])) {
-                       printk("channel list must be continuous! chanlist[%i]=%d but must be %d or %d!\n",
-                              i, CR_CHAN(chanlist[i]), nowmustbechan,
-                              CR_CHAN(chanlist[0]));
+
+               if (last_aref == AREF_DIFF)
+                       next_chan = (next_chan + 1) % s->n_chan;
+               if (chan != next_chan) {
+                       dev_err(dev->class_dev,
+                               "channel list must be continuous! chanlist[%i]=%d but must be %d or %d!\n",
+                               i, chan, next_chan, chan0);
                        return 0;
                }
-               chansegment[i] = chanlist[i]; /* next correct channel in list */
-       }
 
-       for (i = 0, segpos = 0; i < n_chan; i++) {
-               if (chanlist[i] != chansegment[i % seglen]) {
-                       printk("bad channel, reference or range number! chanlist[%i]=%d,%d,%d and not %d,%d,%d!\n",
-                              i, CR_CHAN(chansegment[i]),
-                              CR_RANGE(chansegment[i]),
-                              CR_AREF(chansegment[i]),
-                              CR_CHAN(chanlist[i % seglen]),
-                              CR_RANGE(chanlist[i % seglen]),
-                              CR_AREF(chansegment[i % seglen]));
+               /* next correct channel in list */
+               chansegment[i] = cmd->chanlist[i];
+               last_aref = aref;
+       }
+       seglen = i;
+
+       for (i = 0; i < cmd->chanlist_len; i++) {
+               if (cmd->chanlist[i] != chansegment[i % seglen]) {
+                       dev_err(dev->class_dev,
+                               "bad channel, reference or range number! chanlist[%i]=%d,%d,%d and not %d,%d,%d!\n",
+                               i, CR_CHAN(chansegment[i]),
+                               CR_RANGE(chansegment[i]),
+                               CR_AREF(chansegment[i]),
+                               CR_CHAN(cmd->chanlist[i % seglen]),
+                               CR_RANGE(cmd->chanlist[i % seglen]),
+                               CR_AREF(chansegment[i % seglen]));
                        return 0;
                }
        }