staging: comedi: pcl812: clarify dma channel request in pcl812_attach()

All the board types that can do DMA can use DMA channels 3 or 1. Remove
the 'DMAbits', which is a mask of the valid channels, from the boardinfo
and replace it with a bit-field flag 'has_dma'.

Refactor pcl812_attach() to use the new flag and remove the need for the
goto.

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/pcl812.c b/drivers/staging/comedi/drivers/pcl812.c
index 7b97dbe7276f09a1e2accfcddc1648f563c6f89e..7f3d32080090721d74f6cbf18fbcf79f08b0d00f 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl812.c
+++ b/drivers/staging/comedi/drivers/pcl812.c
@@ -340,7 +340,7 @@ struct pcl812_board {
        unsigned int ai_ns_min;
        const struct comedi_lrange *rangelist_ai;
        unsigned int IRQbits;
-       unsigned char DMAbits;
+       unsigned int has_dma:1;
        unsigned char haveMPC508;
 };
 
@@ -356,7 +356,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 33000,
                .rangelist_ai   = &range_bipolar10,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "pcl812pg",
                .board_type     = boardPCL812PG,
@@ -368,7 +368,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 33000,
                .rangelist_ai   = &range_pcl812pg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "acl8112pg",
                .board_type     = boardPCL812PG,
@@ -380,7 +380,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl812pg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "acl8112dg",
                .board_type     = boardACL8112,
@@ -393,7 +393,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112dg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
                .haveMPC508     = 1,
        }, {
                .name           = "acl8112hg",
@@ -407,7 +407,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112hg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
                .haveMPC508     = 1,
        }, {
                .name           = "a821pgl",
@@ -454,7 +454,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112dg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "a822pgh",
                .board_type     = boardACL8112,
@@ -467,7 +467,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112hg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "a823pgl",
                .board_type     = boardACL8112,
@@ -480,7 +480,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 8000,
                .rangelist_ai   = &range_acl8112dg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "a823pgh",
                .board_type     = boardACL8112,
@@ -493,7 +493,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 8000,
                .rangelist_ai   = &range_acl8112hg_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        }, {
                .name           = "pcl813",
                .board_type     = boardPCL813,
@@ -530,7 +530,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl813b2_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
                .haveMPC508     = 1,
        }, {
                .name           = "a826pg",
@@ -544,7 +544,7 @@ static const struct pcl812_board boardtypes[] = {
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl813b2_ai,
                .IRQbits        = 0xdcfc,
-               .DMAbits        = 0x0a,
+               .has_dma        = 1,
        },
 };
 
@@ -1290,7 +1290,6 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        const struct pcl812_board *board = comedi_board(dev);
        struct pcl812_private *devpriv;
        int ret, subdev;
-       unsigned int dma;
        unsigned long pages;
        struct comedi_subdevice *s;
        int n_subdevices;
@@ -1310,24 +1309,18 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                        dev->irq = it->options[1];
        }
 
-       dma = 0;
-       devpriv->dma = dma;
-       if (!dev->irq)
-               goto no_dma;    /* if we haven't IRQ, we can't use DMA */
-       if (board->DMAbits != 0) {      /* board support DMA */
-               dma = it->options[2];
-               if (((1 << dma) & board->DMAbits) == 0) {
-                       dev_err(dev->class_dev,
-                               "DMA is out of allowed range, FAIL!\n");
-                       return -EINVAL; /* Bad DMA */
-               }
-               ret = request_dma(dma, dev->board_name);
+       /* we need an IRQ to do DMA on channel 3 or 1 */
+       if (dev->irq && board->has_dma &&
+           (it->options[2] == 3 || it->options[2] == 1)) {
+               ret = request_dma(it->options[2], dev->board_name);
                if (ret) {
                        dev_err(dev->class_dev,
-                               "unable to allocate DMA %u, FAIL!\n", dma);
-                       return -EBUSY;  /* DMA isn't free */
+                               "unable to request DMA channel %d\n",
+                               it->options[2]);
+                       return -EBUSY;
                }
-               devpriv->dma = dma;
+               devpriv->dma = it->options[2];
+
                pages = 1;      /* we want 8KB */
                devpriv->dmabuf[0] = __get_dma_pages(GFP_KERNEL, pages);
                if (!devpriv->dmabuf[0]) {
@@ -1352,7 +1345,6 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                devpriv->hwdmaptr[1] = virt_to_bus((void *)devpriv->dmabuf[1]);
                devpriv->hwdmasize[1] = PAGE_SIZE * (1 << pages);
        }
-no_dma:
 
        n_subdevices = 0;
        if (board->n_aichan > 0)