staging: comedi: adv_pci1710: introduce pci171x_ai_read_sample()

Introduce a helper function to read an analog input sample, check for
channel dropout, and mask the sample to the maxdata of the subdevice.

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 719497c..6068f40 100644 (file)
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -276,31 +276,6 @@ struct pci1710_private {
                                         * internal state */
 };
 
-static int pci171x_ai_dropout(struct comedi_device *dev,
-                             struct comedi_subdevice *s,
-                             unsigned int chan,
-                             unsigned int val)
-{
-       const struct boardtype *board = dev->board_ptr;
-       struct pci1710_private *devpriv = dev->private;
-
-       if (!board->is_pci1713) {
-               /*
-                * The upper 4 bits of the 16-bit sample are the channel number
-                * that the sample was acquired from. Verify that this channel
-                * number matches the expected channel number.
-                */
-               val >>= 12;
-               if (val != devpriv->act_chanlist[chan]) {
-                       dev_err(dev->class_dev,
-                               "A/D data droput: received from channel %d, expected %d\n",
-                               val, devpriv->act_chanlist[chan]);
-                       return -ENODATA;
-               }
-       }
-       return 0;
-}
-
 static int pci171x_ai_check_chanlist(struct comedi_device *dev,
                                     struct comedi_subdevice *s,
                                     struct comedi_cmd *cmd)
@@ -416,6 +391,35 @@ static int pci171x_ai_eoc(struct comedi_device *dev,
        return -EBUSY;
 }
 
+static int pci171x_ai_read_sample(struct comedi_device *dev,
+                                 struct comedi_subdevice *s,
+                                 unsigned int cur_chan,
+                                 unsigned int *val)
+{
+       const struct boardtype *board = dev->board_ptr;
+       struct pci1710_private *devpriv = dev->private;
+       unsigned int sample;
+       unsigned int chan;
+
+       sample = inw(dev->iobase + PCI171x_AD_DATA);
+       if (!board->is_pci1713) {
+               /*
+                * The upper 4 bits of the 16-bit sample are the channel number
+                * that the sample was acquired from. Verify that this channel
+                * number matches the expected channel number.
+                */
+               chan = sample >> 12;
+               if (chan != devpriv->act_chanlist[cur_chan]) {
+                       dev_err(dev->class_dev,
+                               "A/D data droput: received from channel %d, expected %d\n",
+                               chan, devpriv->act_chanlist[cur_chan]);
+                       return -ENODATA;
+               }
+       }
+       *val = sample & s->maxdata;
+       return 0;
+}
+
 static int pci171x_ai_insn_read(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn,
@@ -443,12 +447,11 @@ static int pci171x_ai_insn_read(struct comedi_device *dev,
                if (ret)
                        break;
 
-               val = inw(dev->iobase + PCI171x_AD_DATA);
-               ret = pci171x_ai_dropout(dev, s, chan, val);
+               ret = pci171x_ai_read_sample(dev, s, chan, &val);
                if (ret)
                        break;
 
-               data[i] = val & s->maxdata;
+               data[i] = val;
        }
 
        outb(0, dev->iobase + PCI171x_CLRFIFO);
@@ -677,14 +680,12 @@ static void pci1710_handle_every_sample(struct comedi_device *dev,
        outb(0, dev->iobase + PCI171x_CLRINT);  /*  clear our INT request */
 
        for (; !(inw(dev->iobase + PCI171x_STATUS) & Status_FE);) {
-               val = inw(dev->iobase + PCI171x_AD_DATA);
-               ret = pci171x_ai_dropout(dev, s, s->async->cur_chan, val);
+               ret = pci171x_ai_read_sample(dev, s, s->async->cur_chan, &val);
                if (ret) {
                        s->async->events |= COMEDI_CB_ERROR;
                        break;
                }
 
-               val &= s->maxdata;
                comedi_buf_write_samples(s, &val, 1);
 
                if (cmd->stop_src == TRIG_COUNT &&
@@ -707,15 +708,12 @@ static int move_block_from_fifo(struct comedi_device *dev,
        int i;
 
        for (i = 0; i < n; i++) {
-               val = inw(dev->iobase + PCI171x_AD_DATA);
-
-               ret = pci171x_ai_dropout(dev, s, s->async->cur_chan, val);
+               ret = pci171x_ai_read_sample(dev, s, s->async->cur_chan, &val);
                if (ret) {
                        s->async->events |= COMEDI_CB_ERROR;
                        return ret;
                }
 
-               val &= s->maxdata;
                comedi_buf_write_samples(s, &val, 1);
        }
        return 0;