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staging: comedi: ni_labpc: allow board to attach without dma

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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@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2013-03-22 09:55:30 -07:00 committed by Greg Kroah-Hartman
parent 0229979a32
commit 19a40abf5e
1 changed files with 13 additions and 20 deletions
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33
drivers/staging/comedi/drivers/ni_labpc.c
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@ -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 (devpriv->dma_buffer) {
ret = request_dma(dma_chan, dev->board_name);
if (ret == 0) {
unsigned long dma_flags;
if (request_dma(dma_chan, dev->board_name)) {
dev_err(dev->class_dev,
"failed to allocate dma channel %u\n",
dma_chan);
return -EINVAL;
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