staging: comedi: das16: introduce das16_ai_set_mux_range()

Introduce a helper function to program the mux and gain for analog input
single channel (*insn_read) and multi-channel (*do_cmd) operations.

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/das16.c b/drivers/staging/comedi/drivers/das16.c
index 86e90d549de7475c9467f26985b8933276186989..2c20311120f18638d251225a79bf88f36d69a11a 100644 (file)
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -537,6 +537,29 @@ static void das16_timer_interrupt(unsigned long arg)
        spin_unlock_irqrestore(&dev->spinlock, flags);
 }
 
+static void das16_ai_set_mux_range(struct comedi_device *dev,
+                                  unsigned int first_chan,
+                                  unsigned int last_chan,
+                                  unsigned int range)
+{
+       const struct das16_board *board = dev->board_ptr;
+
+       /* set multiplexer */
+       outb(first_chan | (last_chan << 4), dev->iobase + DAS16_MUX_REG);
+
+       /* some boards do not have programmable gain */
+       if (board->ai_pg == das16_pg_none)
+               return;
+
+       /*
+        * Set gain (this is also burst rate register but according to
+        * computer boards manual, burst rate does nothing, even on
+        * keithley cards).
+        */
+       outb((das16_gainlists[board->ai_pg])[range],
+            dev->iobase + DAS16_GAIN_REG);
+}
+
 static int das16_ai_check_chanlist(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_cmd *cmd)
@@ -687,14 +710,15 @@ static unsigned int das16_set_pacer(struct comedi_device *dev, unsigned int ns,
 
 static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s)
 {
-       const struct das16_board *board = dev->board_ptr;
        struct das16_private_struct *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
+       unsigned int first_chan = CR_CHAN(cmd->chanlist[0]);
+       unsigned int last_chan = CR_CHAN(cmd->chanlist[cmd->chanlist_len - 1]);
+       unsigned int range = CR_RANGE(cmd->chanlist[0]);
        unsigned int byte;
        unsigned long flags;
-       int range;
 
        if (cmd->flags & CMDF_PRIORITY) {
                dev_err(dev->class_dev,
@@ -705,19 +729,8 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s)
        if (devpriv->can_burst)
                outb(DAS1600_CONV_DISABLE, dev->iobase + DAS1600_CONV_REG);
 
-       /*  set scan limits */
-       byte = CR_CHAN(cmd->chanlist[0]);
-       byte |= CR_CHAN(cmd->chanlist[cmd->chanlist_len - 1]) << 4;
-       outb(byte, dev->iobase + DAS16_MUX_REG);
-
-       /* set gain (this is also burst rate register but according to
-        * computer boards manual, burst rate does nothing, even on
-        * keithley cards) */
-       if (board->ai_pg != das16_pg_none) {
-               range = CR_RANGE(cmd->chanlist[0]);
-               outb((das16_gainlists[board->ai_pg])[range],
-                    dev->iobase + DAS16_GAIN_REG);
-       }
+       /* set mux and range for chanlist scan */
+       das16_ai_set_mux_range(dev, first_chan, last_chan, range);
 
        /* set counter mode and counts */
        cmd->convert_arg = das16_set_pacer(dev, cmd->convert_arg, cmd->flags);
@@ -826,21 +839,14 @@ static int das16_ai_insn_read(struct comedi_device *dev,
                              struct comedi_insn *insn,
                              unsigned int *data)
 {
-       const struct das16_board *board = dev->board_ptr;
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        unsigned int val;
        int ret;
        int i;
 
-       /* set multiplexer */
-       outb(chan | (chan << 4), dev->iobase + DAS16_MUX_REG);
-
-       /* set gain */
-       if (board->ai_pg != das16_pg_none) {
-               outb((das16_gainlists[board->ai_pg])[range],
-                    dev->iobase + DAS16_GAIN_REG);
-       }
+       /* set mux and range for single channel */
+       das16_ai_set_mux_range(dev, chan, chan, range);
 
        for (i = 0; i < insn->n; i++) {
                /* trigger conversion */