staging: comedi: das1800: tidy up das1800_init_dma()

Refactor this function so that a for loop can be used to request and
set up the two DMA descriptors.

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 2d376fd..df28d36 100644 (file)
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -1228,15 +1228,24 @@ static int das1800_do_wbits(struct comedi_device *dev,
        return insn->n;
 }
 
-static int das1800_init_dma(struct comedi_device *dev, unsigned int dma0,
-                           unsigned int dma1)
+static int das1800_init_dma(struct comedi_device *dev,
+                           struct comedi_devconfig *it)
 {
        struct das1800_private *devpriv = dev->private;
        struct das1800_dma_desc *dma;
+       unsigned int *dma_chan;
        unsigned long flags;
+       int i;
+
+       /*
+        * it->options[2] is DMA channel 0
+        * it->options[3] is DMA channel 1
+        *
+        * Encode the DMA channels into 2 digit hexadecimal for switch.
+        */
+       dma_chan = &it->options[2];
 
-       /* encode dma0 and dma1 into 2 digit hexadecimal for switch */
-       switch ((dma0 & 0x7) | (dma1 << 4)) {
+       switch ((dma_chan[0] & 0x7) | (dma_chan[1] << 4)) {
        case 0x5:       /*  dma0 == 5 */
                devpriv->dma_bits |= DMA_CH5;
                break;
@@ -1265,33 +1274,24 @@ static int das1800_init_dma(struct comedi_device *dev, unsigned int dma0,
                return -EINVAL;
        }
 
-       dma = &devpriv->dma_desc[0];
-       if (request_dma(dma0, dev->driver->driver_name)) {
-               dev_err(dev->class_dev,
-                       "failed to allocate dma channel %i\n", dma0);
-               return -EINVAL;
-       }
-       dma->chan = dma0;
-       dma->virt_addr = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
-       if (!dma->virt_addr)
-               return -ENOMEM;
-       flags = claim_dma_lock();
-       disable_dma(dma->chan);
-       set_dma_mode(dma->chan, DMA_MODE_READ);
-       release_dma_lock(flags);
+       for (i = 0; i < 2; i++) {
+               dma = &devpriv->dma_desc[i];
 
-       if (dma1) {
-               dma = &devpriv->dma_desc[1];
-               if (request_dma(dma1, dev->driver->driver_name)) {
+               if (dma_chan[i] == 0)
+                       break;
+
+               if (request_dma(dma_chan[i], dev->board_name)) {
                        dev_err(dev->class_dev,
                                "failed to allocate dma channel %i\n",
-                               dma1);
+                               dma_chan[i]);
                        return -EINVAL;
                }
-               dma->chan = dma1;
+               dma->chan = dma_chan[i];
+
                dma->virt_addr = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
                if (!dma->virt_addr)
                        return -ENOMEM;
+
                flags = claim_dma_lock();
                disable_dma(dma->chan);
                set_dma_mode(dma->chan, DMA_MODE_READ);
@@ -1366,8 +1366,6 @@ static int das1800_attach(struct comedi_device *dev,
        struct das1800_private *devpriv;
        struct comedi_subdevice *s;
        unsigned int irq = it->options[1];
-       unsigned int dma0 = it->options[2];
-       unsigned int dma1 = it->options[3];
        int board;
        int ret;
 
@@ -1430,8 +1428,8 @@ static int das1800_attach(struct comedi_device *dev,
        }
 
        /* an irq and one dma channel is required to use dma */
-       if (dev->irq & dma0) {
-               ret = das1800_init_dma(dev, dma0, dma1);
+       if (dev->irq & it->options[2]) {
+               ret = das1800_init_dma(dev, it);
                if (ret < 0)
                        return ret;
        }