staging: comedi: addi_apci_3501: 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/addi_apci_3501.c b/drivers/staging/comedi/drivers/addi_apci_3501.c
index d9594f4..56781c1 100644 (file)
--- a/drivers/staging/comedi/drivers/addi_apci_3501.c
+++ b/drivers/staging/comedi/drivers/addi_apci_3501.c
@@ -104,9 +104,9 @@ static int apci3501_ao_insn_write(struct comedi_device *dev,
 {
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
-       unsigned int val = 0;
-       int i;
+       unsigned int cfg = APCI3501_AO_DATA_CHAN(chan);
        int ret;
+       int i;
 
        /*
         * All analog output channels have the same output range.
@@ -117,14 +117,14 @@ static int apci3501_ao_insn_write(struct comedi_device *dev,
        if (range) {
                outl(0, dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
        } else {
-               val |= APCI3501_AO_DATA_BIPOLAR;
+               cfg |= APCI3501_AO_DATA_BIPOLAR;
                outl(APCI3501_AO_CTRL_BIPOLAR,
                     dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
        }
 
-       val |= APCI3501_AO_DATA_CHAN(chan);
-
        for (i = 0; i < insn->n; i++) {
+               unsigned int val = data[i];
+
                if (range == 1) {
                        if (data[i] > 0x1fff) {
                                dev_err(dev->class_dev,
@@ -137,8 +137,10 @@ static int apci3501_ao_insn_write(struct comedi_device *dev,
                if (ret)
                        return ret;
 
-               outl(val | APCI3501_AO_DATA_VAL(data[i]),
+               outl(cfg | APCI3501_AO_DATA_VAL(val),
                     dev->iobase + APCI3501_AO_DATA_REG);
+
+               s->readback[chan] = val;
        }
 
        return insn->n;
@@ -360,6 +362,11 @@ static int apci3501_auto_attach(struct comedi_device *dev,
                s->maxdata      = 0x3fff;
                s->range_table  = &apci3501_ao_range;
                s->insn_write   = apci3501_ao_insn_write;
+               s->insn_read    = comedi_readback_insn_read;
+
+               ret = comedi_alloc_subdev_readback(s);
+               if (ret)
+                       return ret;
        } else {
                s->type         = COMEDI_SUBD_UNUSED;
        }