staging: comedi: dt282x: tidy up the irq support in dt282x_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.

Also, only call dt282x_grab_dma() if we have an irq since interrupt support
is needed to support dma.

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, 30 insertions, 54 deletions

diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index c4ffedbdde21..d2f95bf94f44 100644
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -1118,9 +1118,9 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
         const struct dt282x_board *board = comedi_board(dev);
         struct dt282x_private *devpriv;
-        int i, irq;
-        int ret;
         struct comedi_subdevice *s;
+        int ret;
+        int i;
 
         ret = comedi_request_region(dev, it->options[0], DT2821_SIZE);
         if (ret)
@@ -1144,53 +1144,23 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
         }
         /* should do board test */
 
-        irq = it->options[opt_irq];
-#if 0
-        if (irq < 0) {
-                unsigned long flags;
-                int irqs;
-
-                save_flags(flags);
-                sti();
-                irqs = probe_irq_on();
-
-                /* trigger interrupt */
-
-                udelay(100);
-
-                irq = probe_irq_off(irqs);
-                restore_flags(flags);
-                if (0 /* error */)
-                        printk(KERN_ERR " error probing irq (bad)");
-        }
-#endif
-        if (irq > 0) {
-                printk(KERN_INFO " ( irq = %d )", irq);
-                ret = request_irq(irq, dt282x_interrupt, 0,
+        if (it->options[opt_irq] > 0) {
+                ret = request_irq(it->options[opt_irq], dt282x_interrupt, 0,
                                   dev->board_name, dev);
-                if (ret < 0) {
-                        printk(KERN_ERR " failed to get irq\n");
-                        return -EIO;
-                }
-                dev->irq = irq;
-        } else if (irq == 0) {
-                printk(KERN_INFO " (no irq)");
-        } else {
-#if 0
-                printk(KERN_INFO " (probe returned multiple irqs--bad)");
-#else
-                printk(KERN_INFO " (irq probe not implemented)");
-#endif
+                if (ret == 0)
+                        dev->irq = it->options[opt_irq];
         }
 
         devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
         if (!devpriv)
                 return -ENOMEM;
 
-        ret = dt282x_grab_dma(dev, it->options[opt_dma1],
-                              it->options[opt_dma2]);
-        if (ret < 0)
-                return ret;
+        if (dev->irq) {
+                ret = dt282x_grab_dma(dev, it->options[opt_dma1],
+                                      it->options[opt_dma2]);
+                if (ret < 0)
+                        return ret;
+        }
 
         ret = comedi_alloc_subdevices(dev, 3);
         if (ret)
@@ -1198,22 +1168,25 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 
         s = &dev->subdevices[0];
 
-        dev->read_subdev = s;
         /* ai subdevice */
         s->type = COMEDI_SUBD_AI;
-        s->subdev_flags = SDF_READABLE | SDF_CMD_READ |
+        s->subdev_flags = SDF_READABLE |
             ((it->options[opt_diff]) ? SDF_DIFF : SDF_COMMON);
         s->n_chan =
             (it->options[opt_diff]) ? board->adchan_di : board->adchan_se;
         s->insn_read = dt282x_ai_insn_read;
-        s->do_cmdtest = dt282x_ai_cmdtest;
-        s->do_cmd = dt282x_ai_cmd;
-        s->cancel = dt282x_ai_cancel;
         s->maxdata = (1 << board->adbits) - 1;
-        s->len_chanlist = 16;
         s->range_table =
             opt_ai_range_lkup(board->ispgl, it->options[opt_ai_range]);
         devpriv->ad_2scomp = it->options[opt_ai_twos];
+        if (dev->irq) {
+                dev->read_subdev = s;
+                s->subdev_flags |= SDF_CMD_READ;
+                s->len_chanlist = 16;
+                s->do_cmdtest = dt282x_ai_cmdtest;
+                s->do_cmd = dt282x_ai_cmd;
+                s->cancel = dt282x_ai_cancel;
+        }
 
         s = &dev->subdevices[1];
 
@@ -1221,15 +1194,10 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
         if (s->n_chan) {
                 /* ao subsystem */
                 s->type = COMEDI_SUBD_AO;
-                dev->write_subdev = s;
-                s->subdev_flags = SDF_WRITABLE | SDF_CMD_WRITE;
+                s->subdev_flags = SDF_WRITABLE;
                 s->insn_read = dt282x_ao_insn_read;
                 s->insn_write = dt282x_ao_insn_write;
-                s->do_cmdtest = dt282x_ao_cmdtest;
-                s->do_cmd = dt282x_ao_cmd;
-                s->cancel = dt282x_ao_cancel;
                 s->maxdata = (1 << board->dabits) - 1;
-                s->len_chanlist = 2;
                 s->range_table_list = devpriv->darangelist;
                 devpriv->darangelist[0] =
                     opt_ao_range_lkup(it->options[opt_ao0_range]);
@@ -1237,6 +1205,14 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                     opt_ao_range_lkup(it->options[opt_ao1_range]);
                 devpriv->da0_2scomp = it->options[opt_ao0_twos];
                 devpriv->da1_2scomp = it->options[opt_ao1_twos];
+                if (dev->irq) {
+                        dev->write_subdev = s;
+                        s->subdev_flags |= SDF_CMD_WRITE;
+                        s->len_chanlist = 2;
+                        s->do_cmdtest = dt282x_ao_cmdtest;
+                        s->do_cmd = dt282x_ao_cmd;
+                        s->cancel = dt282x_ao_cancel;
+                }
         } else {
                 s->type = COMEDI_SUBD_UNUSED;
         }