staging: comedi: pcl818: use comedi_subdevice 'readback'

Use the new comedi_subdevice 'readback' member and the core provided
(*insn_read) for the readback of the analog output subdevice channels.

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 000dbf8..36c7751 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -319,7 +319,6 @@ struct pcl818_private {
        unsigned int act_chanlist_len;  /*  how long is actual MUX list */
        unsigned int act_chanlist_pos;  /*  actual position in MUX list */
        unsigned int ai_data_len;       /*  len of data buffer */
-       unsigned int ao_readback[2];
        unsigned int divisor1;
        unsigned int divisor2;
        unsigned int usefifo:1;
@@ -937,32 +936,18 @@ static int pcl818_ao_insn_write(struct comedi_device *dev,
                                struct comedi_insn *insn,
                                unsigned int *data)
 {
-       struct pcl818_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int val = s->readback[chan];
        int i;
 
        for (i = 0; i < insn->n; i++) {
-               devpriv->ao_readback[chan] = data[i];
-               outb((data[i] & 0x000f) << 4,
+               val = data[i];
+               outb((val & 0x000f) << 4,
                     dev->iobase + PCL818_AO_LSB_REG(chan));
-               outb((data[i] & 0x0ff0) >> 4,
+               outb((val & 0x0ff0) >> 4,
                     dev->iobase + PCL818_AO_MSB_REG(chan));
        }
-
-       return insn->n;
-}
-
-static int pcl818_ao_insn_read(struct comedi_device *dev,
-                              struct comedi_subdevice *s,
-                              struct comedi_insn *insn,
-                              unsigned int *data)
-{
-       struct pcl818_private *devpriv = dev->private;
-       unsigned int chan = CR_CHAN(insn->chanspec);
-       int i;
-
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->ao_readback[chan];
+       s->readback[chan] = val;
 
        return insn->n;
 }
@@ -1172,8 +1157,6 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                s->n_chan       = board->n_aochan;
                s->maxdata      = 0x0fff;
                s->range_table  = &range_unipolar5;
-               s->insn_read    = pcl818_ao_insn_read;
-               s->insn_write   = pcl818_ao_insn_write;
                if (board->is_818) {
                        if ((it->options[4] == 1) || (it->options[4] == 10))
                                s->range_table = &range_unipolar10;
@@ -1185,6 +1168,12 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                        if (it->options[5] == 2)
                                s->range_table = &range_unknown;
                }
+               s->insn_write   = pcl818_ao_insn_write;
+               s->insn_read    = comedi_readback_insn_read;
+
+               ret = comedi_alloc_subdev_readback(s);
+               if (ret)
+                       return ret;
        } else {
                s->type         = COMEDI_SUBD_UNUSED;
        }