staging: comedi: ni_at_a2150: introduce a2150_alloc_irq_dma()

This driver requires an IRQ and DMA in order to support async commands.

For aesthetics, introduce a helper function to request the IRQ and DMA
channels and allocate the DMA buffer. Since the async command support
is optional, make the helper function handle any request/allocation
errors and allow the driver to still attach without async command support.

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/ni_at_a2150.c b/drivers/staging/comedi/drivers/ni_at_a2150.c
index 7380dac..11b1681 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_at_a2150.c
+++ b/drivers/staging/comedi/drivers/ni_at_a2150.c
@@ -676,6 +676,50 @@ static int a2150_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
        return n;
 }
 
+static void a2150_alloc_irq_dma(struct comedi_device *dev,
+                               struct comedi_devconfig *it)
+{
+       struct a2150_private *devpriv = dev->private;
+       unsigned int irq_num = it->options[1];
+       unsigned int dma_chan = it->options[2];
+
+       /*
+        * Only IRQs 15, 14, 12-9, and 7-3 are valid.
+        * Only DMA channels 7-5 and 3-0 are valid.
+        *
+        * Both must be valid for async command support.
+        */
+       if (irq_num > 15 || dma_chan > 7 ||
+           !((1 << irq_num) & 0xdef8) || !((1 << dma_chan) & 0xef))
+               return;
+
+       /*
+        * Request the IRQ and DMA channels and allocate the DMA buffer.
+        * If the requests or allocation fail async command supprt will
+        * not be available.
+        */
+       if (request_irq(irq_num, a2150_interrupt, 0, dev->board_name, dev))
+               return;
+       if (request_dma(dma_chan, dev->board_name)) {
+               free_irq(irq_num, dev);
+               return;
+       }
+       devpriv->dma_buffer = kmalloc(A2150_DMA_BUFFER_SIZE,
+                                     GFP_KERNEL | GFP_DMA);
+       if (!devpriv->dma_buffer) {
+               free_dma(dma_chan);
+               free_irq(irq_num, dev);
+               return;
+       }
+
+       dev->irq = irq_num;
+       devpriv->dma = dma_chan;
+       devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);
+
+       disable_dma(dma_chan);
+       set_dma_mode(dma_chan, DMA_MODE_READ);
+}
+
 /* probes board type, returns offset */
 static int a2150_probe(struct comedi_device *dev)
 {
@@ -689,8 +733,6 @@ static int a2150_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        const struct a2150_board *thisboard;
        struct a2150_private *devpriv;
        struct comedi_subdevice *s;
-       unsigned int irq = it->options[1];
-       unsigned int dma = it->options[2];
        static const int timeout = 2000;
        int i;
        int ret;
@@ -711,31 +753,7 @@ static int a2150_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        thisboard = dev->board_ptr;
        dev->board_name = thisboard->name;
 
-       if ((irq >= 3 && irq <= 7) || (irq >= 9 && irq <= 12) ||
-           irq == 14 || irq == 15) {
-               ret = request_irq(irq, a2150_interrupt, 0,
-                                 dev->board_name, dev);
-               if (ret == 0) {
-                       devpriv->irq_dma_bits |= IRQ_LVL_BITS(irq);
-                       dev->irq = irq;
-               }
-       }
-
-       if (dev->irq && dma <= 7 && dma != 4) {
-               ret = request_dma(dma, dev->board_name);
-               if (ret == 0) {
-                       devpriv->dma = dma;
-                       devpriv->dma_buffer = kmalloc(A2150_DMA_BUFFER_SIZE,
-                                                     GFP_KERNEL | GFP_DMA);
-                       if (!devpriv->dma_buffer)
-                               return -ENOMEM;
-
-                       disable_dma(dma);
-                       set_dma_mode(dma, DMA_MODE_READ);
-
-                       devpriv->irq_dma_bits |= DMA_CHAN_BITS(dma);
-               }
-       }
+       a2150_alloc_irq_dma(dev, it);
 
        ret = comedi_alloc_subdevices(dev, 1);
        if (ret)
@@ -749,7 +767,7 @@ static int a2150_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s->maxdata = 0xffff;
        s->range_table = &range_a2150;
        s->insn_read = a2150_ai_rinsn;
-       if (dev->irq && devpriv->dma) {
+       if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = s->n_chan;