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Commit ecb11d8c authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: dt282x: introduce dt282x_ao_setup_dma() 



Introduce a helper function to read the analog output samples from the
async buffer and prep the DMA.

Use comedi_buf_read_samples() to read the analog output samples from
the async buffer.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7bd7d905

drivers/staging/comedi/drivers/dt282x.c

+21 −21
Original line number Diff line number Diff line
@@ -449,13 +449,29 @@ static void dt282x_munge(struct comedi_device *dev, 
	}

}



static unsigned int dt282x_ao_setup_dma(struct comedi_device *dev,

					struct comedi_subdevice *s,

					int cur_dma)

{

	struct dt282x_private *devpriv = dev->private;

	void *ptr = devpriv->dma[cur_dma].buf;

	unsigned int nsamples = devpriv->dma_maxsize / bytes_per_sample(s);

	unsigned int nbytes;



	nbytes = comedi_buf_read_samples(s, ptr, nsamples);

	if (nbytes)

		dt282x_prep_ao_dma(dev, cur_dma, nbytes);

	else

		dev_err(dev->class_dev, "AO underrun\n");



	return nbytes;

}



static void dt282x_ao_dma_interrupt(struct comedi_device *dev,

				    struct comedi_subdevice *s)

{

	struct dt282x_private *devpriv = dev->private;

	int cur_dma = devpriv->current_dma_index;

	void *ptr = devpriv->dma[cur_dma].buf;

	int size;



	outw(devpriv->supcsr | DT2821_SUPCSR_CLRDMADNE,

	     dev->iobase + DT2821_SUPCSR_REG);
@@ -464,13 +480,8 @@ static void dt282x_ao_dma_interrupt(struct comedi_device *dev, 


	devpriv->current_dma_index = 1 - cur_dma;



	size = cfc_read_array_from_buffer(s, ptr, devpriv->dma_maxsize);

	if (size == 0) {

		dev_err(dev->class_dev, "AO underrun\n");

	if (!dt282x_ao_setup_dma(dev, s, cur_dma))

		s->async->events |= COMEDI_CB_OVERFLOW;

	} else {

		dt282x_prep_ao_dma(dev, cur_dma, size);

	}

}



static void dt282x_ai_dma_interrupt(struct comedi_device *dev,
@@ -916,26 +927,15 @@ static int dt282x_ao_inttrig(struct comedi_device *dev, 
{

	struct dt282x_private *devpriv = dev->private;

	struct comedi_cmd *cmd = &s->async->cmd;

	int size;



	if (trig_num != cmd->start_src)

		return -EINVAL;



	size = cfc_read_array_from_buffer(s, devpriv->dma[0].buf,

					  devpriv->dma_maxsize);

	if (size == 0) {

		dev_err(dev->class_dev, "AO underrun\n");

	if (!dt282x_ao_setup_dma(dev, s, 0))

		return -EPIPE;

	}

	dt282x_prep_ao_dma(dev, 0, size);



	size = cfc_read_array_from_buffer(s, devpriv->dma[1].buf,

					  devpriv->dma_maxsize);

	if (size == 0) {

		dev_err(dev->class_dev, "AO underrun\n");

	if (!dt282x_ao_setup_dma(dev, s, 1))

		return -EPIPE;

	}

	dt282x_prep_ao_dma(dev, 1, size);



	outw(devpriv->supcsr | DT2821_SUPCSR_STRIG,

	     dev->iobase + DT2821_SUPCSR_REG);