[alsa-devel] [PATCH 2/2] ALSA sound driver for the AT73C213 DAC using Atmel SSC driver
hskinnemoen at atmel.com
Tue Jul 17 10:48:59 CEST 2007
On Tue, 17 Jul 2007 10:37:21 +0200
Hans-Christian Egtvedt <hcegtvedt at atmel.com> wrote:
> > > + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &at73c213_playback_ops);
> > > +
> > > + retval = snd_pcm_lib_preallocate_pages_for_all(chip->pcm,
> > > + SNDRV_DMA_TYPE_DEV,
> > > + snd_dma_continuous_data(GFP_KERNEL),
> > > + 64 * 1024, 64 * 1024);
> > For SNDRV_DMA_TYPE_DEV, pass the struct device pointer of the device
> > to the third argument. Then the pre-allocator will allocate the
> > memory via dma_alloc_coherent() with the givn device. If it's not
> > appropriate, SNDRV_DMA_TYPE_CONTINUOUS type. Anyway,
> > snd_dma_continuous_data() is only for SNDRV_DMA_TYPE_CONTINUOUS.
> Ok, applied. Using &chip->spi->dev.
Not that I think it matters at the moment, but that's not entirely
correct. The memory is used for DMA transfers to the SSC controller,
not the SPI device, so you should pass the SSC's struct device here.
In other words, I think you should use &chip->ssc->pdev->dev.
More information about the Alsa-devel