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>

diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index c4ffedbdde21f8e5c1906045126efea6b0ff92ce..d2f95bf94f44316a9ef338b227aef809abc86c91 100644 (file)
--- 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;
        }