staging: comedi: ni_labpc: cleanup local var declarations in labpc_ai_cmd()

Determine the scan_mode early and get the proper chanspec so that
the chan, range, and aref can be determined when the variables are
declared.

labpc_ai_chanlist_invalid() checks that all the range and aref values
in the chanlist are the same so, for consistency, use the same chanspec
used to get the chan.

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

diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c
index 56d60847f820cb1e72a7c856c14988a286e60d09..3672ba897b866786689fd0d6f86da7c70eb399a9 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc.c
+++ b/drivers/staging/comedi/drivers/ni_labpc.c
@@ -850,16 +850,18 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 {
        const struct labpc_boardinfo *board = comedi_board(dev);
        struct labpc_private *devpriv = dev->private;
-       int channel, range, aref;
-       int ret;
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
+       enum scan_mode mode = labpc_ai_scan_mode(cmd);
+       unsigned int chanspec = (mode == MODE_MULT_CHAN_UP)
+                               ? cmd->chanlist[cmd->chanlist_len - 1]
+                               : cmd->chanlist[0];
+       unsigned int chan = CR_CHAN(chanspec);
+       unsigned int range = CR_RANGE(chanspec);
+       unsigned int aref = CR_AREF(chanspec);
        enum transfer_type xfer;
-       enum scan_mode mode;
        unsigned long flags;
-
-       range = CR_RANGE(cmd->chanlist[0]);
-       aref = CR_AREF(cmd->chanlist[0]);
+       int ret;
 
        /* make sure board is disabled before setting up acquisition */
        spin_lock_irqsave(&dev->spinlock, flags);
@@ -916,7 +918,6 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        } else
                xfer = fifo_not_empty_transfer;
        devpriv->current_transfer = xfer;
-       mode = labpc_ai_scan_mode(cmd);
 
        /*  setup cmd6 register for 1200 boards */
        if (board->register_layout == labpc_1200_layout) {
@@ -951,15 +952,11 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 
        /* setup channel list, etc (cmd1 register) */
        devpriv->cmd1 = 0;
-       if (mode == MODE_MULT_CHAN_UP)
-               channel = CR_CHAN(cmd->chanlist[cmd->chanlist_len - 1]);
-       else
-               channel = CR_CHAN(cmd->chanlist[0]);
        /* munge channel bits for differential / scan disabled mode */
        if ((mode == MODE_SINGLE_CHAN || mode == MODE_SINGLE_CHAN_INTERVAL) &&
            aref == AREF_DIFF)
-               channel *= 2;
-       devpriv->cmd1 |= ADC_CHAN_BITS(channel);
+               chan *= 2;
+       devpriv->cmd1 |= ADC_CHAN_BITS(chan);
        devpriv->cmd1 |= board->ai_range_code[range];
        devpriv->write_byte(devpriv->cmd1, dev->iobase + COMMAND1_REG);
        /* manual says to set scan enable bit on second pass */