Re: [alsa-devel] [PATCH 2/3] Add ALSA driver for Atmel Audio Bitstream DAC

At Wed, 4 Feb 2009 13:18:35 +0100, Hans-Christian Egtvedt wrote:

...

...

+static int at32_abdac_trigger(struct snd_pcm_substream *substream, int cmd) +{

• struct at32_abdac *dac = snd_pcm_substream_chip(substream);
• int retval = -EINVAL;
• switch (cmd) {
• case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
• case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
• case SNDRV_PCM_TRIGGER_START:

• clk_enable(dac->sample_clk);
  

• retval = dw_dma_cyclic_start(dac->dma.chan);
  

• if (retval)
  

• 	goto out;
  

• dac_writel(dac, CTRL, DAC_BIT(EN));
  

• break;
  

• case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
• case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
• case SNDRV_PCM_TRIGGER_STOP:

• set_bit(DMA_STOP, &dac->flags);
  

• dw_dma_cyclic_stop(dac->dma.chan);
  

• dac_writel(dac, DATA, 0);
  

• dac_writel(dac, CTRL, 0);
  

• clk_disable(dac->sample_clk);
  

• break;
  

No retval is set for these cases?

Nope, they are all void return functions and will always complete successfully.

I meant that retval is kept -EINVAL in the cases for STOP, etc, although the call is successful.

Takashi