staging: comedi: ni_at_a2150: factor out chanlist checking from (*do_cmdtest)

Step 5 of the (*do_cmdtest) validates that the cmd->chanlist is compatible
with the hardware.

For aesthetics, factor out the step 5 code for the analog input async command
support. Tidy up the factored out code.

To minimize the noise, change the comedi_error(), which is a wrapper around
dev_err(), to dev_dbg().

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/ni_at_a2150.c b/drivers/staging/comedi/drivers/ni_at_a2150.c
index 4e39b1f63d818f2c3435a62d955b594715993df9..afbf251ba270676c9df8b5292f42209385282b23 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_at_a2150.c
+++ b/drivers/staging/comedi/drivers/ni_at_a2150.c
@@ -287,14 +287,54 @@ static int a2150_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
        return 0;
 }
 
+static int a2150_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 aref0 = CR_AREF(cmd->chanlist[0]);
+       int i;
+
+       if (cmd->chanlist_len == 2 && (chan0 == 1 || chan0 == 3)) {
+               dev_dbg(dev->class_dev,
+                       "length 2 chanlist must be channels 0,1 or channels 2,3\n");
+               return -EINVAL;
+       }
+
+       if (cmd->chanlist_len == 3) {
+               dev_dbg(dev->class_dev,
+                       "chanlist must have 1,2 or 4 channels\n");
+               return -EINVAL;
+       }
+
+       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 (chan != (chan0 + i)) {
+                       dev_dbg(dev->class_dev,
+                               "entries in chanlist must be consecutive channels, counting upwards\n");
+                       return -EINVAL;
+               }
+
+               if (chan == 2)
+                       aref0 = aref;
+               if (aref != aref0) {
+                       dev_dbg(dev->class_dev,
+                               "channels 0/1 and 2/3 must have the same analog reference\n");
+                       return -EINVAL;
+               }
+       }
+
+       return 0;
+}
+
 static int a2150_ai_cmdtest(struct comedi_device *dev,
                            struct comedi_subdevice *s, struct comedi_cmd *cmd)
 {
        const struct a2150_board *thisboard = comedi_board(dev);
        int err = 0;
        int tmp;
-       int startChan;
-       int i;
 
        /* Step 1 : check if triggers are trivially valid */
 
@@ -348,33 +388,9 @@ static int a2150_ai_cmdtest(struct comedi_device *dev,
        if (err)
                return 4;
 
-       /*  check channel/gain list against card's limitations */
-       if (cmd->chanlist) {
-               startChan = CR_CHAN(cmd->chanlist[0]);
-               for (i = 1; i < cmd->chanlist_len; i++) {
-                       if (CR_CHAN(cmd->chanlist[i]) != (startChan + i)) {
-                               comedi_error(dev,
-                                            "entries in chanlist must be consecutive channels, counting upwards\n");
-                               err++;
-                       }
-               }
-               if (cmd->chanlist_len == 2 && CR_CHAN(cmd->chanlist[0]) == 1) {
-                       comedi_error(dev,
-                                    "length 2 chanlist must be channels 0,1 or channels 2,3");
-                       err++;
-               }
-               if (cmd->chanlist_len == 3) {
-                       comedi_error(dev,
-                                    "chanlist must have 1,2 or 4 channels");
-                       err++;
-               }
-               if (CR_AREF(cmd->chanlist[0]) != CR_AREF(cmd->chanlist[1]) ||
-                   CR_AREF(cmd->chanlist[2]) != CR_AREF(cmd->chanlist[3])) {
-                       comedi_error(dev,
-                                    "channels 0/1 and 2/3 must have the same analog reference");
-                       err++;
-               }
-       }
+       /* Step 5: check channel list if it exists */
+       if (cmd->chanlist && cmd->chanlist_len > 0)
+               err |= a2150_ai_check_chanlist(dev, s, cmd);
 
        if (err)
                return 5;