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staging: comedi: adv_pci1710: tidy up pci171x_ai_check_chanlist()

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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>
This commit is contained in:
H Hartley Sweeten 2014-04-29 11:08:32 -07:00 • committed by Greg Kroah-Hartman
parent 4bac39f6c9
commit b5a7a46693
1 changed files with 46 additions and 45 deletions
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91
drivers/staging/comedi/drivers/adv_pci1710.c
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@ -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;
unsigned int seglen;
int i;
/* correct channel and range number check itself comedi/range.c */
if (n_chan < 1) {
comedi_error(dev, "range/channel list is empty!");
return 0;
}
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])
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");
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]));
return 0;
}
chansegment[i] = chanlist[i]; /* next correct channel in list */
}
/* first channel is always ok */
chansegment[0] = cmd->chanlist[0];
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]));
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 (aref == AREF_DIFF && (chan & 1)) {
dev_err(dev->class_dev,
"Odd channel cannot be differential input!\n");
return 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;
}
/* 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;
}
}