staging: comedi: dt3000: 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, rename the (*insn_write) function and tidy it up a bit.

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/dt3000.c b/drivers/staging/comedi/drivers/dt3000.c
index ca8141e..bcbba09 100644 (file)
--- a/drivers/staging/comedi/drivers/dt3000.c
+++ b/drivers/staging/comedi/drivers/dt3000.c
@@ -245,7 +245,6 @@ static const struct dt3k_boardtype dt3k_boardtypes[] = {
 
 struct dt3k_private {
        unsigned int lock;
-       unsigned int ao_readback[2];
        unsigned int ai_front;
        unsigned int ai_rear;
 };
@@ -545,35 +544,22 @@ static int dt3k_ai_insn(struct comedi_device *dev, struct comedi_subdevice *s,
        return i;
 }
 
-static int dt3k_ao_insn(struct comedi_device *dev, struct comedi_subdevice *s,
-                       struct comedi_insn *insn, unsigned int *data)
+static int dt3k_ao_insn_write(struct comedi_device *dev,
+                             struct comedi_subdevice *s,
+                             struct comedi_insn *insn,
+                             unsigned int *data)
 {
-       struct dt3k_private *devpriv = dev->private;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int val = s->readback[chan];
        int i;
-       unsigned int chan;
 
-       chan = CR_CHAN(insn->chanspec);
        for (i = 0; i < insn->n; i++) {
-               dt3k_writesingle(dev, SUBS_AO, chan, data[i]);
-               devpriv->ao_readback[chan] = data[i];
+               val = data[i];
+               dt3k_writesingle(dev, SUBS_AO, chan, val);
        }
+       s->readback[chan] = val;
 
-       return i;
-}
-
-static int dt3k_ao_insn_read(struct comedi_device *dev,
-                            struct comedi_subdevice *s,
-                            struct comedi_insn *insn, unsigned int *data)
-{
-       struct dt3k_private *devpriv = dev->private;
-       int i;
-       unsigned int chan;
-
-       chan = CR_CHAN(insn->chanspec);
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->ao_readback[chan];
-
-       return i;
+       return insn->n;
 }
 
 static void dt3k_dio_config(struct comedi_device *dev, int bits)
@@ -709,11 +695,15 @@ static int dt3000_auto_attach(struct comedi_device *dev,
        s->type         = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 2;
-       s->insn_read    = dt3k_ao_insn_read;
-       s->insn_write   = dt3k_ao_insn;
        s->maxdata      = (1 << this_board->dabits) - 1;
        s->len_chanlist = 1;
        s->range_table  = &range_bipolar10;
+       s->insn_write   = dt3k_ao_insn_write;
+       s->insn_read    = comedi_readback_insn_read;
+
+       ret = comedi_alloc_subdev_readback(s);
+       if (ret)
+               return ret;
 
        s = &dev->subdevices[2];
        /* dio subsystem */