staging: comedi: rtd520: 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/rtd520.c b/drivers/staging/comedi/drivers/rtd520.c
index 6fc4ed33f66c0eb749d1b4c1460c7acb8c91e60e..7c7911b24166622991d91e63df30bafadb122b00 100644 (file)
--- a/drivers/staging/comedi/drivers/rtd520.c
+++ b/drivers/staging/comedi/drivers/rtd520.c
@@ -380,7 +380,6 @@ struct rtd_private {
        int xfer_count;         /* # to transfer data. 0->1/2FIFO */
        int flags;              /* flag event modes */
        DECLARE_BITMAP(chan_is_bipolar, RTD_MAX_CHANLIST);
-       unsigned int ao_readback[2];
        unsigned fifosz;
 };
 
@@ -1138,7 +1137,7 @@ static int rtd_ao_winsn(struct comedi_device *dev,
                        ((chan == 0) ? LAS1_DAC1_FIFO : LAS1_DAC2_FIFO));
                writew(0, dev->mmio + ((chan == 0) ? LAS0_DAC1 : LAS0_DAC2));
 
-               devpriv->ao_readback[chan] = data[i];
+               s->readback[chan] = data[i];
 
                ret = comedi_timeout(dev, s, insn, rtd_ao_eoc, 0);
                if (ret)
@@ -1149,23 +1148,6 @@ static int rtd_ao_winsn(struct comedi_device *dev,
        return i;
 }
 
-/* AO subdevices should have a read insn as well as a write insn.
- * Usually this means copying a value stored in devpriv. */
-static int rtd_ao_rinsn(struct comedi_device *dev,
-                       struct comedi_subdevice *s, struct comedi_insn *insn,
-                       unsigned int *data)
-{
-       struct rtd_private *devpriv = dev->private;
-       int i;
-       int chan = CR_CHAN(insn->chanspec);
-
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->ao_readback[chan];
-
-
-       return i;
-}
-
 static int rtd_dio_insn_bits(struct comedi_device *dev,
                             struct comedi_subdevice *s,
                             struct comedi_insn *insn,
@@ -1323,7 +1305,11 @@ static int rtd_auto_attach(struct comedi_device *dev,
        s->maxdata      = 0x0fff;
        s->range_table  = &rtd_ao_range;
        s->insn_write   = rtd_ao_winsn;
-       s->insn_read    = rtd_ao_rinsn;
+       s->insn_read    = comedi_readback_insn_read;
+
+       ret = comedi_alloc_subdev_readback(s);
+       if (ret)
+               return ret;
 
        s = &dev->subdevices[2];
        /* digital i/o subdevice */