staging: comedi: amplc_pci230: 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.

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/amplc_pci230.c b/drivers/staging/comedi/drivers/amplc_pci230.c
index 0fd212f..2fc4992 100644 (file)
--- a/drivers/staging/comedi/drivers/amplc_pci230.c
+++ b/drivers/staging/comedi/drivers/amplc_pci230.c
@@ -515,7 +515,6 @@ struct pci230_private {
        spinlock_t ao_stop_spinlock;    /* Spin lock for stopping AO command */
        unsigned long daqio;            /* PCI230's DAQ I/O space */
        unsigned long state;            /* State flags */
-       unsigned int ao_readback[2];    /* Used for AO readback */
        unsigned int ai_scan_count;     /* Number of AI scans remaining */
        unsigned int ai_scan_pos;       /* Current position within AI scan */
        unsigned int ao_scan_count;     /* Number of AO scans remaining.  */
@@ -623,9 +622,6 @@ static inline void pci230_ao_write_nofifo(struct comedi_device *dev,
 {
        struct pci230_private *devpriv = dev->private;
 
-       /* Store unmangled datum to be read back later. */
-       devpriv->ao_readback[chan] = datum;
-
        /* Write mangled datum to appropriate DACOUT register. */
        outw(pci230_ao_mangle_datum(dev, datum),
             devpriv->daqio + ((chan) == 0) ? PCI230_DACOUT1 : PCI230_DACOUT2);
@@ -636,9 +632,6 @@ static inline void pci230_ao_write_fifo(struct comedi_device *dev,
 {
        struct pci230_private *devpriv = dev->private;
 
-       /* Store unmangled datum to be read back later. */
-       devpriv->ao_readback[chan] = datum;
-
        /* Write mangled datum to appropriate DACDATA register. */
        outw(pci230_ao_mangle_datum(dev, datum),
             devpriv->daqio + PCI230P2_DACDATA);
@@ -909,20 +902,16 @@ static int pci230_ai_rinsn(struct comedi_device *dev,
        return n;
 }
 
-/*
- *  COMEDI_SUBD_AO instructions;
- */
-static int pci230_ao_winsn(struct comedi_device *dev,
-                          struct comedi_subdevice *s, struct comedi_insn *insn,
-                          unsigned int *data)
+static int pci230_ao_insn_write(struct comedi_device *dev,
+                               struct comedi_subdevice *s,
+                               struct comedi_insn *insn,
+                               unsigned int *data)
 {
        struct pci230_private *devpriv = dev->private;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int range = CR_RANGE(insn->chanspec);
+       unsigned int val = s->readback[chan];
        int i;
-       int chan, range;
-
-       /* Unpack channel and range. */
-       chan = CR_CHAN(insn->chanspec);
-       range = CR_RANGE(insn->chanspec);
 
        /*
         * Set range - see analogue output range table; 0 => unipolar 10V,
@@ -931,35 +920,13 @@ static int pci230_ao_winsn(struct comedi_device *dev,
        devpriv->ao_bipolar = pci230_ao_bipolar[range];
        outw(range, devpriv->daqio + PCI230_DACCON);
 
-       /*
-        * Writing a list of values to an AO channel is probably not
-        * very useful, but that's how the interface is defined.
-        */
        for (i = 0; i < insn->n; i++) {
-               /* Write value to DAC and store it. */
-               pci230_ao_write_nofifo(dev, data[i], chan);
+               val = data[i];
+               pci230_ao_write_nofifo(dev, val, chan);
        }
+       s->readback[chan] = val;
 
-       /* return the number of samples read/written */
-       return i;
-}
-
-/*
- * AO subdevices should have a read insn as well as a write insn.
- * Usually this means copying a value stored in devpriv.
- */
-static int pci230_ao_rinsn(struct comedi_device *dev,
-                          struct comedi_subdevice *s, struct comedi_insn *insn,
-                          unsigned int *data)
-{
-       struct pci230_private *devpriv = dev->private;
-       int i;
-       int chan = CR_CHAN(insn->chanspec);
-
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->ao_readback[chan];
-
-       return i;
+       return insn->n;
 }
 
 static int pci230_ao_check_chanlist(struct comedi_device *dev,
@@ -1186,6 +1153,8 @@ static void pci230_handle_ao_nofifo(struct comedi_device *dev,
        if (cmd->stop_src == TRIG_COUNT && devpriv->ao_scan_count == 0)
                return;
        for (i = 0; i < cmd->chanlist_len; i++) {
+               unsigned int chan = CR_CHAN(cmd->chanlist[i]);
+
                /* Read sample from Comedi's circular buffer. */
                ret = comedi_buf_get(s, &data);
                if (ret == 0) {
@@ -1194,8 +1163,8 @@ static void pci230_handle_ao_nofifo(struct comedi_device *dev,
                        dev_err(dev->class_dev, "AO buffer underrun\n");
                        return;
                }
-               /* Write value to DAC. */
-               pci230_ao_write_nofifo(dev, data, CR_CHAN(cmd->chanlist[i]));
+               pci230_ao_write_nofifo(dev, data, chan);
+               s->readback[chan] = data;
        }
        async->events |= COMEDI_CB_BLOCK | COMEDI_CB_EOS;
        if (cmd->stop_src == TRIG_COUNT) {
@@ -1271,11 +1240,12 @@ static int pci230_handle_ao_fifo(struct comedi_device *dev,
                /* Process scans. */
                for (n = 0; n < num_scans; n++) {
                        for (i = 0; i < cmd->chanlist_len; i++) {
+                               unsigned int chan = CR_CHAN(cmd->chanlist[i]);
                                unsigned short datum;
 
                                comedi_buf_get(s, &datum);
-                               pci230_ao_write_fifo(dev, datum,
-                                                    CR_CHAN(cmd->chanlist[i]));
+                               pci230_ao_write_fifo(dev, datum, chan);
+                               s->readback[chan] = datum;
                        }
                }
                events |= COMEDI_CB_EOS | COMEDI_CB_BLOCK;
@@ -2777,8 +2747,8 @@ static int pci230_attach_common(struct comedi_device *dev,
                s->n_chan = thisboard->ao_chans;
                s->maxdata = (1 << thisboard->ao_bits) - 1;
                s->range_table = &pci230_ao_range;
-               s->insn_write = pci230_ao_winsn;
-               s->insn_read = pci230_ao_rinsn;
+               s->insn_write = pci230_ao_insn_write;
+               s->insn_read = comedi_readback_insn_read;
                s->len_chanlist = thisboard->ao_chans;
                if (dev->irq) {
                        dev->write_subdev = s;
@@ -2787,6 +2757,10 @@ static int pci230_attach_common(struct comedi_device *dev,
                        s->do_cmdtest = pci230_ao_cmdtest;
                        s->cancel = pci230_ao_cancel;
                }
+
+               rc = comedi_alloc_subdev_readback(s);
+               if (rc)
+                       return rc;
        } else {
                s->type = COMEDI_SUBD_UNUSED;
        }