From 19a40abf5ee320e8f0874116989773b7c071aa08 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Fri, 22 Mar 2013 09:55:30 -0700 Subject: [PATCH] staging: comedi: ni_labpc: allow board to attach without dma 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 Cc: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- 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 a52647a901f6..744db1f5aa25 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 -- 2.30.2