staging: comedi: pcl818: introduce pcl818_ai_write_sample()

This driver can acquire analog input samples during the async command with
DMA, by using the FIFO, or sample-by-sample using the End-Of-Conversion
interrupt. All three methods do the following sequence:

  1) check for channel dropout
  2) add the sample to the async buffer
  3) advance the channel dropout detection and detect the end of the command

Merge this sequence into a new helper function.

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/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c
index 6e5d8bf..a10ce41 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -454,11 +454,12 @@ static int pcl818_ai_eoc(struct comedi_device *dev,
        return -EBUSY;
 }
 
-static bool pcl818_ai_dropout(struct comedi_device *dev,
-                             struct comedi_subdevice *s,
-                             unsigned int chan)
+static bool pcl818_ai_write_sample(struct comedi_device *dev,
+                                  struct comedi_subdevice *s,
+                                  unsigned int chan, unsigned int val)
 {
        struct pcl818_private *devpriv = dev->private;
+       struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int expected_chan;
 
        expected_chan = devpriv->act_chanlist[devpriv->act_chanlist_pos];
@@ -469,16 +470,10 @@ static bool pcl818_ai_dropout(struct comedi_device *dev,
                        (devpriv->usefifo) ? "FIFO" : "IRQ",
                        chan, expected_chan);
                s->async->events |= COMEDI_CB_ERROR;
-               return true;
+               return false;
        }
-       return false;
-}
 
-static bool pcl818_ai_next_chan(struct comedi_device *dev,
-                               struct comedi_subdevice *s)
-{
-       struct pcl818_private *devpriv = dev->private;
-       struct comedi_cmd *cmd = &s->async->cmd;
+       comedi_buf_write_samples(s, &val, 1);
 
        devpriv->act_chanlist_pos++;
        if (devpriv->act_chanlist_pos >= devpriv->act_chanlist_len)
@@ -506,13 +501,7 @@ static void pcl818_handle_eoc(struct comedi_device *dev,
        }
 
        val = pcl818_ai_get_sample(dev, s, &chan);
-
-       if (pcl818_ai_dropout(dev, s, chan))
-               return;
-
-       comedi_buf_write_samples(s, &val, 1);
-
-       pcl818_ai_next_chan(dev, s);
+       pcl818_ai_write_sample(dev, s, chan, val);
 }
 
 static void pcl818_handle_dma(struct comedi_device *dev,
@@ -535,13 +524,7 @@ static void pcl818_handle_dma(struct comedi_device *dev,
                val = ptr[i];
                chan = val & 0xf;
                val = (val >> 4) & s->maxdata;
-
-               if (pcl818_ai_dropout(dev, s, chan))
-                       break;
-
-               comedi_buf_write_samples(s, &val, 1);
-
-               if (!pcl818_ai_next_chan(dev, s))
+               if (!pcl818_ai_write_sample(dev, s, chan, val))
                        break;
        }
 }
@@ -576,13 +559,7 @@ static void pcl818_handle_fifo(struct comedi_device *dev,
 
        for (i = 0; i < len; i++) {
                val = pcl818_ai_get_fifo_sample(dev, s, &chan);
-
-               if (pcl818_ai_dropout(dev, s, chan))
-                       break;
-
-               comedi_buf_write_samples(s, &val, 1);
-
-               if (!pcl818_ai_next_chan(dev, s))
+               if (!pcl818_ai_write_sample(dev, s, chan, val))
                        break;
        }
 }