staging: comedi: amplc_pci224: fix the ao cmd->start_arg use

This driver supports two cmd->start_src values, TRIG_INT and TRIG_EXT. For
TRIG_INT sources, the cmd->start_arg is actually the valid trig_num that is
passed to the async (*inttrig) callback. This driver trivially validates the
arg for this source to be 0.

Refactor the (*inttrig) so that the cmd->start_arg is used to check the trig_num
instead of the open coded value.

For aesthetics, refactor the (*do_cmd) to use if/else instead of the switch when
handling the cmd->start_src. All code paths do the spin lock/unlock so move those
out of the if/else.

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 e99829e58635e1bea4f3275a4f43413e84497fe2..3b9a8b9ae39ca8ab1ecc6d448577677a401d592b 100644 (file)
--- a/drivers/staging/comedi/drivers/amplc_pci224.c
+++ b/drivers/staging/comedi/drivers/amplc_pci224.c
@@ -671,14 +671,13 @@ static void pci224_ao_handle_fifo(struct comedi_device *dev,
        cfc_handle_events(dev, s);
 }
 
-/*
- * Internal trigger function to start acquisition on AO subdevice.
- */
-static int
-pci224_ao_inttrig_start(struct comedi_device *dev, struct comedi_subdevice *s,
-                       unsigned int trignum)
+static int pci224_ao_inttrig_start(struct comedi_device *dev,
+                                  struct comedi_subdevice *s,
+                                  unsigned int trig_num)
 {
-       if (trignum != 0)
+       struct comedi_cmd *cmd = &s->async->cmd;
+
+       if (trig_num != cmd->start_arg)
                return -EINVAL;
 
        s->async->inttrig = NULL;
@@ -1053,23 +1052,15 @@ static int pci224_ao_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
                break;
        }
 
-       /*
-        * Sort out start of acquisition.
-        */
-       switch (cmd->start_src) {
-       case TRIG_INT:
-               spin_lock_irqsave(&devpriv->ao_spinlock, flags);
-               s->async->inttrig = &pci224_ao_inttrig_start;
-               spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
-               break;
-       case TRIG_EXT:
+       spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+       if (cmd->start_src == TRIG_INT) {
+               s->async->inttrig = pci224_ao_inttrig_start;
+       } else {        /* TRIG_EXT */
                /* Enable external interrupt trigger to start acquisition. */
-               spin_lock_irqsave(&devpriv->ao_spinlock, flags);
                devpriv->intsce |= PCI224_INTR_EXT;
                outb(devpriv->intsce, devpriv->iobase1 + PCI224_INT_SCE);
-               spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
-               break;
        }
+       spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
 
        return 0;
 }