staging: comedi: pcl812: 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.

For aesthetics, tidy up pcl812_ao_insn_write().

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/pcl812.c b/drivers/staging/comedi/drivers/pcl812.c
index 803e7790538cb3a3d990d18f717f6ac3ff895126..55620c95cf04b45eb4935ebd680a50ac93a18551 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl812.c
+++ b/drivers/staging/comedi/drivers/pcl812.c
@@ -522,7 +522,6 @@ struct pcl812_private {
        unsigned int dma_runs_to_end;   /*  how many times we must switch DMA buffers */
        unsigned int last_dma_run;      /*  how many bytes to transfer on last DMA buffer */
        unsigned int max_812_ai_mode0_rangewait;        /*  setling time for gain */
-       unsigned int ao_readback[2];    /*  data for AO readback */
        unsigned int divisor1;
        unsigned int divisor2;
        unsigned int use_diff:1;
@@ -1039,32 +1038,16 @@ static int pcl812_ao_insn_write(struct comedi_device *dev,
                                struct comedi_insn *insn,
                                unsigned int *data)
 {
-       struct pcl812_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++) {
-               outb((data[i] & 0xff),
-                    dev->iobase + PCL812_AO_LSB_REG(chan));
-               outb((data[i] >> 8) & 0x0f,
-                    dev->iobase + PCL812_AO_MSB_REG(chan));
-               devpriv->ao_readback[chan] = data[i];
+               val = data[i];
+               outb(val & 0xff, dev->iobase + PCL812_AO_LSB_REG(chan));
+               outb((val >> 8) & 0x0f, dev->iobase + PCL812_AO_MSB_REG(chan));
        }
-
-       return insn->n;
-}
-
-static int pcl812_ao_insn_read(struct comedi_device *dev,
-                              struct comedi_subdevice *s,
-                              struct comedi_insn *insn,
-                              unsigned int *data)
-{
-       struct pcl812_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;
 }
@@ -1336,8 +1319,6 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                s->n_chan       = board->n_aochan;
                s->maxdata      = 0xfff;
                s->range_table  = &range_unipolar5;
-               s->insn_read    = pcl812_ao_insn_read;
-               s->insn_write   = pcl812_ao_insn_write;
                switch (board->board_type) {
                case boardA821:
                        if (it->options[3] == 1)
@@ -1353,6 +1334,13 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                                s->range_table = &range_unknown;
                        break;
                }
+               s->insn_write   = pcl812_ao_insn_write;
+               s->insn_read    = comedi_readback_insn_read;
+
+               ret = comedi_alloc_subdev_readback(s);
+               if (ret)
+                       return ret;
+
                subdev++;
        }