staging: comedi: das1800: reduce indent level of das1800_init_dma()

An IRQ and at least one DMA channel are required to use DMA with this driver.
Move the check to the caller to reduce the indent level of this function.

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/das1800.c b/drivers/staging/comedi/drivers/das1800.c
index be825d21a185ff12de9ff23294dc88a4fd14f230..c415b578f5fbb5fb6e9c0a0e9609a0d6fab049bc 100644 (file)
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -1240,72 +1240,70 @@ static int das1800_init_dma(struct comedi_device *dev, unsigned int dma0,
        struct das1800_private *devpriv = dev->private;
        unsigned long flags;
 
-       /*  need an irq to do dma */
-       if (dev->irq && dma0) {
-               /* encode dma0 and dma1 into 2 digit hexadecimal for switch */
-               switch ((dma0 & 0x7) | (dma1 << 4)) {
-               case 0x5:       /*  dma0 == 5 */
-                       devpriv->dma_bits |= DMA_CH5;
-                       break;
-               case 0x6:       /*  dma0 == 6 */
-                       devpriv->dma_bits |= DMA_CH6;
-                       break;
-               case 0x7:       /*  dma0 == 7 */
-                       devpriv->dma_bits |= DMA_CH7;
-                       break;
-               case 0x65:      /*  dma0 == 5, dma1 == 6 */
-                       devpriv->dma_bits |= DMA_CH5_CH6;
-                       break;
-               case 0x76:      /*  dma0 == 6, dma1 == 7 */
-                       devpriv->dma_bits |= DMA_CH6_CH7;
-                       break;
-               case 0x57:      /*  dma0 == 7, dma1 == 5 */
-                       devpriv->dma_bits |= DMA_CH7_CH5;
-                       break;
-               default:
-                       dev_err(dev->class_dev,
-                               "only supports dma channels 5 through 7\n");
-                       dev_err(dev->class_dev,
-                               "Dual dma only allows the following combinations:\n");
-                       dev_err(dev->class_dev,
-                               "dma 5,6 / 6,7 / or 7,5\n");
-                       return -EINVAL;
-               }
-               if (request_dma(dma0, dev->driver->driver_name)) {
+       /* encode dma0 and dma1 into 2 digit hexadecimal for switch */
+       switch ((dma0 & 0x7) | (dma1 << 4)) {
+       case 0x5:       /*  dma0 == 5 */
+               devpriv->dma_bits |= DMA_CH5;
+               break;
+       case 0x6:       /*  dma0 == 6 */
+               devpriv->dma_bits |= DMA_CH6;
+               break;
+       case 0x7:       /*  dma0 == 7 */
+               devpriv->dma_bits |= DMA_CH7;
+               break;
+       case 0x65:      /*  dma0 == 5, dma1 == 6 */
+               devpriv->dma_bits |= DMA_CH5_CH6;
+               break;
+       case 0x76:      /*  dma0 == 6, dma1 == 7 */
+               devpriv->dma_bits |= DMA_CH6_CH7;
+               break;
+       case 0x57:      /*  dma0 == 7, dma1 == 5 */
+               devpriv->dma_bits |= DMA_CH7_CH5;
+               break;
+       default:
+               dev_err(dev->class_dev,
+                       "only supports dma channels 5 through 7\n");
+               dev_err(dev->class_dev,
+                       "Dual dma only allows the following combinations:\n");
+               dev_err(dev->class_dev,
+                       "dma 5,6 / 6,7 / or 7,5\n");
+               return -EINVAL;
+       }
+       if (request_dma(dma0, dev->driver->driver_name)) {
+               dev_err(dev->class_dev,
+                       "failed to allocate dma channel %i\n", dma0);
+               return -EINVAL;
+       }
+       devpriv->dma0 = dma0;
+       devpriv->dma_current = dma0;
+       if (dma1) {
+               if (request_dma(dma1, dev->driver->driver_name)) {
                        dev_err(dev->class_dev,
-                               "failed to allocate dma channel %i\n", dma0);
+                               "failed to allocate dma channel %i\n",
+                               dma1);
                        return -EINVAL;
                }
-               devpriv->dma0 = dma0;
-               devpriv->dma_current = dma0;
-               if (dma1) {
-                       if (request_dma(dma1, dev->driver->driver_name)) {
-                               dev_err(dev->class_dev,
-                                       "failed to allocate dma channel %i\n",
-                                       dma1);
-                               return -EINVAL;
-                       }
-                       devpriv->dma1 = dma1;
-               }
-               devpriv->ai_buf0 = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
-               if (devpriv->ai_buf0 == NULL)
+               devpriv->dma1 = dma1;
+       }
+       devpriv->ai_buf0 = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
+       if (devpriv->ai_buf0 == NULL)
+               return -ENOMEM;
+       devpriv->dma_current_buf = devpriv->ai_buf0;
+       if (dma1) {
+               devpriv->ai_buf1 =
+                       kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
+               if (devpriv->ai_buf1 == NULL)
                        return -ENOMEM;
-               devpriv->dma_current_buf = devpriv->ai_buf0;
-               if (dma1) {
-                       devpriv->ai_buf1 =
-                           kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
-                       if (devpriv->ai_buf1 == NULL)
-                               return -ENOMEM;
-               }
-               flags = claim_dma_lock();
-               disable_dma(devpriv->dma0);
-               set_dma_mode(devpriv->dma0, DMA_MODE_READ);
-               if (dma1) {
-                       disable_dma(devpriv->dma1);
-                       set_dma_mode(devpriv->dma1, DMA_MODE_READ);
-               }
-               release_dma_lock(flags);
        }
+       flags = claim_dma_lock();
+       disable_dma(devpriv->dma0);
+       set_dma_mode(devpriv->dma0, DMA_MODE_READ);
+       if (dma1) {
+               disable_dma(devpriv->dma1);
+               set_dma_mode(devpriv->dma1, DMA_MODE_READ);
+       }
+       release_dma_lock(flags);
+
        return 0;
 }
 
@@ -1437,9 +1435,12 @@ static int das1800_attach(struct comedi_device *dev,
                }
        }
 
-       ret = das1800_init_dma(dev, dma0, dma1);
-       if (ret < 0)
-               return ret;
+       /* an irq and one dma channel is required to use dma */
+       if (dev->irq & dma0) {
+               ret = das1800_init_dma(dev, dma0, dma1);
+               if (ret < 0)
+                       return ret;
+       }
 
        if (devpriv->ai_buf0 == NULL) {
                devpriv->ai_buf0 =