staging: comedi: dmm32at: tidy up the irq support in dmm32at_attach()

An irq is only needed by this driver in order to support async commands.
Since it is optional, modify the attach so that if the request_irq() fails
the attach does not fail.

Remove the printk noise about the irq.

Only hookup the async command support if the request_irq() was successful.

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>

1 files changed, 14 insertions, 18 deletions

diff --git a/drivers/staging/comedi/drivers/dmm32at.c b/drivers/staging/comedi/drivers/dmm32at.c
index 6fb8ce1d110c..1831f3288ca8 100644
--- a/drivers/staging/comedi/drivers/dmm32at.c
+++ b/drivers/staging/comedi/drivers/dmm32at.c
@@ -670,9 +670,6 @@ static int dmm32at_attach(struct comedi_device *dev,
         int ret;
         struct comedi_subdevice *s;
         unsigned char aihi, ailo, fifostat, aistat, intstat, airback;
-        unsigned int irq;
-
-        irq = it->options[1];
 
         ret = comedi_request_region(dev, it->options[0], DMM32AT_MEMSIZE);
         if (ret)
@@ -717,14 +714,11 @@ static int dmm32at_attach(struct comedi_device *dev,
                 return -EIO;
         }
 
-        /* board is there, register interrupt */
-        if (irq) {
-                ret = request_irq(irq, dmm32at_isr, 0, dev->board_name, dev);
-                if (ret < 0) {
-                        printk(KERN_ERR "dmm32at: irq conflict\n");
-                        return ret;
-                }
-                dev->irq = irq;
+        if (it->options[1]) {
+                ret = request_irq(it->options[1], dmm32at_isr, 0,
+                                  dev->board_name, dev);
+                if (ret == 0)
+                        dev->irq = it->options[1];
         }
 
         devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
@@ -736,20 +730,22 @@ static int dmm32at_attach(struct comedi_device *dev,
                 return ret;
 
         s = &dev->subdevices[0];
-        dev->read_subdev = s;
         /* analog input subdevice */
         s->type = COMEDI_SUBD_AI;
         /* we support single-ended (ground) and differential */
-        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF | SDF_CMD_READ;
+        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
         s->n_chan = 32;
         s->maxdata = 0xffff;
         s->range_table = &dmm32at_airanges;
-        s->len_chanlist = 32;   /* This is the maximum chanlist length that
-                                   the board can handle */
         s->insn_read = dmm32at_ai_rinsn;
-        s->do_cmd = dmm32at_ai_cmd;
-        s->do_cmdtest = dmm32at_ai_cmdtest;
-        s->cancel = dmm32at_ai_cancel;
+        if (dev->irq) {
+                dev->read_subdev = s;
+                s->subdev_flags |= SDF_CMD_READ;
+                s->len_chanlist = 32;
+                s->do_cmd = dmm32at_ai_cmd;
+                s->do_cmdtest = dmm32at_ai_cmdtest;
+                s->cancel = dmm32at_ai_cancel;
+        }
 
         s = &dev->subdevices[1];
         /* analog output subdevice */