staging: comedi: amplc_pci224: 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_pci224.c b/drivers/staging/comedi/drivers/amplc_pci224.c
index 0b056cfd013645b0cb1f69a7011fd99ce147452c..ba247741adaf0f9e2e75005298936188c7193851 100644 (file)
--- a/drivers/staging/comedi/drivers/amplc_pci224.c
+++ b/drivers/staging/comedi/drivers/amplc_pci224.c
@@ -374,7 +374,6 @@ struct pci224_private {
        unsigned long iobase1;
        unsigned long state;
        spinlock_t ao_spinlock; /* spinlock for AO command handling */
-       unsigned int *ao_readback;
        unsigned short *ao_scan_vals;
        unsigned char *ao_scan_order;
        int intr_cpuid;
@@ -398,8 +397,6 @@ pci224_ao_set_data(struct comedi_device *dev, int chan, int range,
        struct pci224_private *devpriv = dev->private;
        unsigned short mangled;
 
-       /* Store unmangled data for readback. */
-       devpriv->ao_readback[chan] = data;
        /* Enable the channel. */
        outw(1 << chan, dev->iobase + PCI224_DACCEN);
        /* Set range and reset FIFO. */
@@ -424,53 +421,23 @@ pci224_ao_set_data(struct comedi_device *dev, int chan, int range,
        inw(dev->iobase + PCI224_SOFTTRIG);
 }
 
-/*
- * 'insn_write' function for AO subdevice.
- */
-static int
-pci224_ao_insn_write(struct comedi_device *dev, struct comedi_subdevice *s,
-                    struct comedi_insn *insn, unsigned int *data)
-{
-       int i;
-       int chan, range;
-
-       /* Unpack channel and range. */
-       chan = CR_CHAN(insn->chanspec);
-       range = CR_RANGE(insn->chanspec);
-
-       /*
-        * 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++)
-               pci224_ao_set_data(dev, chan, range, data[i]);
-
-       return i;
-}
-
-/*
- * 'insn_read' function for AO subdevice.
- *
- * N.B. The value read will not be valid if the DAC channel has
- * never been written successfully since the device was attached
- * or since the channel has been used by an AO streaming write
- * command.
- */
-static int
-pci224_ao_insn_read(struct comedi_device *dev, struct comedi_subdevice *s,
-                   struct comedi_insn *insn, unsigned int *data)
+static int pci224_ao_insn_write(struct comedi_device *dev,
+                               struct comedi_subdevice *s,
+                               struct comedi_insn *insn,
+                               unsigned int *data)
 {
-       struct pci224_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;
-
-       chan = CR_CHAN(insn->chanspec);
-
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->ao_readback[chan];
 
+       for (i = 0; i < insn->n; i++) {
+               val = data[i];
+               pci224_ao_set_data(dev, chan, range, val);
+       }
+       s->readback[chan] = val;
 
-       return i;
+       return insn->n;
 }
 
 /*
@@ -1094,13 +1061,6 @@ pci224_auto_attach(struct comedi_device *dev, unsigned long context_model)
        dev->iobase = pci_resource_start(pci_dev, 3);
        irq = pci_dev->irq;
 
-       /* Allocate readback buffer for AO channels. */
-       devpriv->ao_readback = kmalloc(sizeof(devpriv->ao_readback[0]) *
-                                      thisboard->ao_chans, GFP_KERNEL);
-       if (!devpriv->ao_readback)
-               return -ENOMEM;
-
-
        /* Allocate buffer to hold values for AO channel scan. */
        devpriv->ao_scan_vals = kmalloc(sizeof(devpriv->ao_scan_vals[0]) *
                                        thisboard->ao_chans, GFP_KERNEL);
@@ -1140,7 +1100,7 @@ pci224_auto_attach(struct comedi_device *dev, unsigned long context_model)
        s->maxdata = (1 << thisboard->ao_bits) - 1;
        s->range_table = thisboard->ao_range;
        s->insn_write = pci224_ao_insn_write;
-       s->insn_read = pci224_ao_insn_read;
+       s->insn_read = comedi_readback_insn_read;
        s->len_chanlist = s->n_chan;
        dev->write_subdev = s;
        s->do_cmd = pci224_ao_cmd;
@@ -1148,6 +1108,10 @@ pci224_auto_attach(struct comedi_device *dev, unsigned long context_model)
        s->cancel = pci224_ao_cancel;
        s->munge = pci224_ao_munge;
 
+       ret = comedi_alloc_subdev_readback(s);
+       if (ret)
+               return ret;
+
        if (irq) {
                ret = request_irq(irq, pci224_interrupt, IRQF_SHARED,
                                  dev->board_name, dev);
@@ -1169,7 +1133,6 @@ static void pci224_detach(struct comedi_device *dev)
        if (dev->irq)
                free_irq(dev->irq, dev);
        if (devpriv) {
-               kfree(devpriv->ao_readback);
                kfree(devpriv->ao_scan_vals);
                kfree(devpriv->ao_scan_order);
        }