staging: comedi: adv_pci1710: don't check the chanlist twice

The chanlist is checked in Step 5 of the (*do_cmdtest) there is no
reason to check it again in the (*do_cmd). The only reason its done
again is to get the actual 'seglen', the non-repeating length of the
chanlist.

Save the 'seglen' found by pci171x_ai_check_chanlist() in the private
data and use that in the (*do_cmd). Rename the private data member to
clarify it. Also, remove the unused 'act_chanlist_pos' member from the
private data.

Refactor the error handling in pci171x_ai_check_chanlist() so it returns
and errno for failure and 0 for success.

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 da1309b80691f732a27a35ee093e1a5d4eb3f6a0..f83c382c1eaa6e33141cfeace33fac8834676cfc 100644 (file)
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -310,8 +310,7 @@ struct pci1710_private {
        unsigned int ai_et_MuxVal;
        unsigned int ai_et_div1, ai_et_div2;
        unsigned int act_chanlist[32];  /*  list of scanned channel */
-       unsigned char act_chanlist_len; /*  len of scanlist */
-       unsigned char act_chanlist_pos; /*  actual position in MUX list */
+       unsigned char saved_seglen;     /* len of the non-repeating chanlist */
        unsigned char da_ranges;        /*  copy of D/A outpit range register */
        unsigned short ao_data[4];      /*  data output buffer */
        unsigned int cnt0_write_wait;   /* after a write, wait for update of the
@@ -330,6 +329,7 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
                                     struct comedi_subdevice *s,
                                     struct comedi_cmd *cmd)
 {
+       struct pci1710_private *devpriv = dev->private;
        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;
@@ -337,8 +337,10 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
        unsigned int seglen;
        int i;
 
-       if (cmd->chanlist_len == 1)
-               return 1; /* seglen=1 */
+       if (cmd->chanlist_len == 1) {
+               devpriv->saved_seglen = cmd->chanlist_len;
+               return 0;
+       }
 
        /* first channel is always ok */
        chansegment[0] = cmd->chanlist[0];
@@ -353,7 +355,7 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
                if (aref == AREF_DIFF && (chan & 1)) {
                        dev_err(dev->class_dev,
                                "Odd channel cannot be differential input!\n");
-                       return 0;
+                       return -EINVAL;
                }
 
                if (last_aref == AREF_DIFF)
@@ -362,7 +364,7 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
                        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;
+                       return -EINVAL;
                }
 
                /* next correct channel in list */
@@ -381,10 +383,12 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
                                CR_CHAN(cmd->chanlist[i % seglen]),
                                CR_RANGE(cmd->chanlist[i % seglen]),
                                CR_AREF(chansegment[i % seglen]));
-                       return 0;
+                       return -EINVAL;
                }
        }
-       return seglen;
+       devpriv->saved_seglen = seglen;
+
+       return 0;
 }
 
 static void setup_channel_list(struct comedi_device *dev,
@@ -396,9 +400,6 @@ static void setup_channel_list(struct comedi_device *dev,
        struct pci1710_private *devpriv = dev->private;
        unsigned int i, range, chanprog;
 
-       devpriv->act_chanlist_len = seglen;
-       devpriv->act_chanlist_pos = 0;
-
        for (i = 0; i < seglen; i++) {  /*  store range list to card */
                chanprog = muxonechan[CR_CHAN(chanlist[i])];
                outw(chanprog, dev->iobase + PCI171x_MUX); /* select channel */
@@ -953,7 +954,6 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        struct pci1710_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int divisor1 = 0, divisor2 = 0;
-       unsigned int seglen;
        int mode;
 
        if (cmd->convert_src == TRIG_TIMER) {
@@ -967,10 +967,8 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 
        start_pacer(dev, -1, 0, 0);     /*  stop pacer */
 
-       seglen = pci171x_ai_check_chanlist(dev, s, cmd);
-       if (seglen < 1)
-               return -EINVAL;
-       setup_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len, seglen);
+       setup_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len,
+                          devpriv->saved_seglen);
 
        outb(0, dev->iobase + PCI171x_CLRFIFO);
        outb(0, dev->iobase + PCI171x_CLRINT);
@@ -1104,7 +1102,9 @@ static int pci171x_ai_cmdtest(struct comedi_device *dev,
 
        /* Step 5: check channel list */
 
-       if (!pci171x_ai_check_chanlist(dev, s, cmd))
+       err |= pci171x_ai_check_chanlist(dev, s, cmd);
+
+       if (err)
                return 5;
 
        return 0;