staging: comedi: icp_multi: 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/icp_multi.c b/drivers/staging/comedi/drivers/icp_multi.c
index a98cef2..40a297c 100644 (file)
--- a/drivers/staging/comedi/drivers/icp_multi.c
+++ b/drivers/staging/comedi/drivers/icp_multi.c
@@ -116,7 +116,6 @@ struct icp_multi_private {
        unsigned char act_chanlist_len; /*  len of scanlist */
        unsigned char act_chanlist_pos; /*  actual position in MUX list */
        unsigned int *ai_chanlist;      /*  actaul chanlist */
-       unsigned short ao_data[4];      /*  data output buffer */
        unsigned int do_data;   /*  Remember digital output data */
 };
 
@@ -240,14 +239,15 @@ static int icp_multi_ao_eoc(struct comedi_device *dev,
        return -EBUSY;
 }
 
-static int icp_multi_insn_write_ao(struct comedi_device *dev,
+static int icp_multi_ao_insn_write(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_insn *insn,
                                   unsigned int *data)
 {
        struct icp_multi_private *devpriv = dev->private;
-       int n, chan, range;
-       int ret;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int range = CR_RANGE(insn->chanspec);
+       int i;
 
        /*  Disable D/A conversion ready interrupt */
        devpriv->IntEnable &= ~DAC_READY;
@@ -257,10 +257,6 @@ static int icp_multi_insn_write_ao(struct comedi_device *dev,
        devpriv->IntStatus |= DAC_READY;
        writew(devpriv->IntStatus, dev->mmio + ICP_MULTI_INT_STAT);
 
-       /*  Get channel number and range */
-       chan = CR_CHAN(insn->chanspec);
-       range = CR_RANGE(insn->chanspec);
-
        /*  Set up range and channel data */
        /*  Bit 4 = 1 : Bipolar */
        /*  Bit 5 = 0 : 5V */
@@ -272,7 +268,10 @@ static int icp_multi_insn_write_ao(struct comedi_device *dev,
 
        writew(devpriv->DacCmdStatus, dev->mmio + ICP_MULTI_DAC_CSR);
 
-       for (n = 0; n < insn->n; n++) {
+       for (i = 0; i < insn->n; i++) {
+               unsigned int val = data[i];
+               int ret;
+
                /*  Wait for analogue output data register to be
                 *  ready for new data, or get fed up waiting */
                ret = comedi_timeout(dev, s, insn, icp_multi_ao_eoc, 0);
@@ -287,42 +286,20 @@ static int icp_multi_insn_write_ao(struct comedi_device *dev,
                        writew(devpriv->IntStatus,
                               dev->mmio + ICP_MULTI_INT_STAT);
 
-                       /*  Clear data received */
-                       devpriv->ao_data[chan] = 0;
-
                        return ret;
                }
 
-               /*  Write data to analogue output data register */
-               writew(data[n], dev->mmio + ICP_MULTI_AO);
+               writew(val, dev->mmio + ICP_MULTI_AO);
 
                /*  Set DAC_ST bit to write the data to selected channel */
                devpriv->DacCmdStatus |= DAC_ST;
                writew(devpriv->DacCmdStatus, dev->mmio + ICP_MULTI_DAC_CSR);
                devpriv->DacCmdStatus &= ~DAC_ST;
 
-               /*  Save analogue output data */
-               devpriv->ao_data[chan] = data[n];
+               s->readback[chan] = val;
        }
 
-       return n;
-}
-
-static int icp_multi_insn_read_ao(struct comedi_device *dev,
-                                 struct comedi_subdevice *s,
-                                 struct comedi_insn *insn, unsigned int *data)
-{
-       struct icp_multi_private *devpriv = dev->private;
-       int n, chan;
-
-       /*  Get channel number */
-       chan = CR_CHAN(insn->chanspec);
-
-       /*  Read analogue outputs */
-       for (n = 0; n < insn->n; n++)
-               data[n] = devpriv->ao_data[chan];
-
-       return n;
+       return insn->n;
 }
 
 static int icp_multi_insn_bits_di(struct comedi_device *dev,
@@ -518,8 +495,12 @@ static int icp_multi_auto_attach(struct comedi_device *dev,
        s->maxdata = 0x0fff;
        s->len_chanlist = 4;
        s->range_table = &range_analog;
-       s->insn_write = icp_multi_insn_write_ao;
-       s->insn_read = icp_multi_insn_read_ao;
+       s->insn_write = icp_multi_ao_insn_write;
+       s->insn_read = comedi_readback_insn_read;
+
+       ret = comedi_alloc_subdev_readback(s);
+       if (ret)
+               return ret;
 
        s = &dev->subdevices[2];
        s->type = COMEDI_SUBD_DI;