staging: comedi: cb_pcimdda: 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.

Remove the unused private data and its allocation.

For aesthetics, rename the (*insn_write) and (*insn_read) functions.

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/cb_pcimdda.c b/drivers/staging/comedi/drivers/cb_pcimdda.c
index 49b24d0..361213c 100644 (file)
--- a/drivers/staging/comedi/drivers/cb_pcimdda.c
+++ b/drivers/staging/comedi/drivers/cb_pcimdda.c
@@ -90,21 +90,14 @@ Configuration Options: not applicable, uses PCI auto config
 #define PCIMDDA_DA_CHAN(x)             (0x00 + (x) * 2)
 #define PCIMDDA_8255_BASE_REG          0x0c
 
-#define MAX_AO_READBACK_CHANNELS       6
-
-struct cb_pcimdda_private {
-       unsigned int ao_readback[MAX_AO_READBACK_CHANNELS];
-};
-
-static int cb_pcimdda_ao_winsn(struct comedi_device *dev,
-                              struct comedi_subdevice *s,
-                              struct comedi_insn *insn,
-                              unsigned int *data)
+static int cb_pcimdda_ao_insn_write(struct comedi_device *dev,
+                                   struct comedi_subdevice *s,
+                                   struct comedi_insn *insn,
+                                   unsigned int *data)
 {
-       struct cb_pcimdda_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned long offset = dev->iobase + PCIMDDA_DA_CHAN(chan);
-       unsigned int val = 0;
+       unsigned int val = s->readback[chan];
        int i;
 
        for (i = 0; i < insn->n; i++) {
@@ -122,45 +115,31 @@ static int cb_pcimdda_ao_winsn(struct comedi_device *dev,
                outb(val & 0x00ff, offset);
                outb((val >> 8) & 0x00ff, offset + 1);
        }
-
-       /* Cache the last value for readback */
-       devpriv->ao_readback[chan] = val;
+       s->readback[chan] = val;
 
        return insn->n;
 }
 
-static int cb_pcimdda_ao_rinsn(struct comedi_device *dev,
-                              struct comedi_subdevice *s,
-                              struct comedi_insn *insn,
-                              unsigned int *data)
+static int cb_pcimdda_ao_insn_read(struct comedi_device *dev,
+                                  struct comedi_subdevice *s,
+                                  struct comedi_insn *insn,
+                                  unsigned int *data)
 {
-       struct cb_pcimdda_private *devpriv = dev->private;
-       int chan = CR_CHAN(insn->chanspec);
-       unsigned long offset = dev->iobase + PCIMDDA_DA_CHAN(chan);
-       int i;
-
-       for (i = 0; i < insn->n; i++) {
-               /* Initiate the simultaneous transfer */
-               inw(offset);
+       unsigned int chan = CR_CHAN(insn->chanspec);
 
-               data[i] = devpriv->ao_readback[chan];
-       }
+       /* Initiate the simultaneous transfer */
+       inw(dev->iobase + PCIMDDA_DA_CHAN(chan));
 
-       return insn->n;
+       return comedi_readback_insn_read(dev, s, insn, data);
 }
 
 static int cb_pcimdda_auto_attach(struct comedi_device *dev,
                                            unsigned long context_unused)
 {
        struct pci_dev *pcidev = comedi_to_pci_dev(dev);
-       struct cb_pcimdda_private *devpriv;
        struct comedi_subdevice *s;
        int ret;
 
-       devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
-       if (!devpriv)
-               return -ENOMEM;
-
        ret = comedi_pci_enable(dev);
        if (ret)
                return ret;
@@ -177,8 +156,12 @@ static int cb_pcimdda_auto_attach(struct comedi_device *dev,
        s->n_chan       = 6;
        s->maxdata      = 0xffff;
        s->range_table  = &range_bipolar5;
-       s->insn_write   = cb_pcimdda_ao_winsn;
-       s->insn_read    = cb_pcimdda_ao_rinsn;
+       s->insn_write   = cb_pcimdda_ao_insn_write;
+       s->insn_read    = cb_pcimdda_ao_insn_read;
+
+       ret = comedi_alloc_subdev_readback(s);
+       if (ret)
+               return ret;
 
        s = &dev->subdevices[1];
        /* digital i/o subdevice */