If the dma channel is not available this driver will still work
with interrupts for the analog input subdevice command support.
In addition, only dma channels 1 and 3 are valid for the ISA
devices.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/ni_labpc.c | 35 +++++++++++++------------------
1 file changed, 14 insertions(+), 21 deletions(-)
diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c
index a52647a..744db1f 100644
--- a/drivers/staging/comedi/drivers/ni_labpc.c
+++ b/drivers/staging/comedi/drivers/ni_labpc.c
@@ -1673,30 +1673,23 @@ int labpc_common_attach(struct comedi_device *dev, unsigned long iobase,
}
#ifdef CONFIG_ISA_DMA_API
- /* grab dma channel */
- if (dma_chan > 3) {
- dev_err(dev->class_dev, "invalid dma channel %u\n", dma_chan);
- return -EINVAL;
- } else if (dma_chan) {
- unsigned long dma_flags;
-
- /* allocate dma buffer */
+ if (dma_chan == 1 || dma_chan == 3) {
devpriv->dma_buffer = kmalloc(dma_buffer_size,
GFP_KERNEL | GFP_DMA);
- if (devpriv->dma_buffer == NULL)
- return -ENOMEM;
-
- if (request_dma(dma_chan, dev->board_name)) {
- dev_err(dev->class_dev,
- "failed to allocate dma channel %u\n",
- dma_chan);
- return -EINVAL;
+ if (devpriv->dma_buffer) {
+ ret = request_dma(dma_chan, dev->board_name);
+ if (ret == 0) {
+ unsigned long dma_flags;
+
+ devpriv->dma_chan = dma_chan;
+ dma_flags = claim_dma_lock();
+ disable_dma(devpriv->dma_chan);
+ set_dma_mode(devpriv->dma_chan, DMA_MODE_READ);
+ release_dma_lock(dma_flags);
+ } else {
+ kfree(devpriv->dma_buffer);
+ }
}
- devpriv->dma_chan = dma_chan;
- dma_flags = claim_dma_lock();
- disable_dma(devpriv->dma_chan);
- set_dma_mode(devpriv->dma_chan, DMA_MODE_READ);
- release_dma_lock(dma_flags);
}
#endif
--
1.8.1.4
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