staging: comedi: ni_labpc_common: use subdevice readback for 'caldac'

Use the comedi_subdevice 'readback' member and the core provided (*insn_read)
to handle the readback of the write-only caldac subdevice. Remove the then unused
'caldac' member from the private data.

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/ni_labpc.h b/drivers/staging/comedi/drivers/ni_labpc.h
index f6e5cd15a4091bf80a1e9af6ff57659d2b77ce66..3261e226cc3daa2eb88bd7e801496c581589c2db 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc.h
+++ b/drivers/staging/comedi/drivers/ni_labpc.h
@@ -72,8 +72,6 @@ struct labpc_private {
        enum transfer_type current_transfer;
        /* stores contents of board's eeprom */
        unsigned int eeprom_data[EEPROM_SIZE];
-       /* stores settings of calibration dacs */
-       unsigned int caldac[16];
        /*
         * function pointers so we can use inb/outb or readb/writeb as
         * appropriate

diff --git a/drivers/staging/comedi/drivers/ni_labpc_common.c b/drivers/staging/comedi/drivers/ni_labpc_common.c
index 4abca1d1db72a39f8c3360f6df510610b8a8c666..548d3df08525515dd2a1206492cbe72b2ce40b83 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc_common.c
+++ b/drivers/staging/comedi/drivers/ni_labpc_common.c
@@ -1174,7 +1174,6 @@ static int labpc_calib_insn_write(struct comedi_device *dev,
                                  struct comedi_insn *insn,
                                  unsigned int *data)
 {
-       struct labpc_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
 
        /*
@@ -1184,30 +1183,15 @@ static int labpc_calib_insn_write(struct comedi_device *dev,
        if (insn->n > 0) {
                unsigned int val = data[insn->n - 1];
 
-               if (devpriv->caldac[chan] != val) {
+               if (s->readback[chan] != val) {
                        write_caldac(dev, chan, val);
-                       devpriv->caldac[chan] = val;
+                       s->readback[chan] = val;
                }
        }
 
        return insn->n;
 }
 
-static int labpc_calib_insn_read(struct comedi_device *dev,
-                                struct comedi_subdevice *s,
-                                struct comedi_insn *insn,
-                                unsigned int *data)
-{
-       struct labpc_private *devpriv = dev->private;
-       unsigned int chan = CR_CHAN(insn->chanspec);
-       int i;
-
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->caldac[chan];
-
-       return insn->n;
-}
-
 static int labpc_eeprom_insn_write(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_insn *insn,
@@ -1345,12 +1329,15 @@ int labpc_common_attach(struct comedi_device *dev,
                s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
                s->n_chan       = 16;
                s->maxdata      = 0xff;
-               s->insn_read    = labpc_calib_insn_read;
                s->insn_write   = labpc_calib_insn_write;
 
+               ret = comedi_alloc_subdev_readback(s);
+               if (ret)
+                       return ret;
+
                for (i = 0; i < s->n_chan; i++) {
                        write_caldac(dev, i, s->maxdata / 2);
-                       devpriv->caldac[i] = s->maxdata / 2;
+                       s->readback[i] = s->maxdata / 2;
                }
        } else {
                s->type         = COMEDI_SUBD_UNUSED;