Messages in this thread | | | Date | Wed, 22 May 2013 19:26:53 +0200 | From | Lars-Peter Clausen <> | Subject | Re: [PATCH] ASoC: Add support for BCM2708 |
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On 05/22/2013 04:10 PM, Florian Meier wrote: [...] > diff --git a/sound/soc/bcm2708/bcm2708-i2s.c b/sound/soc/bcm2708/bcm2708-i2s.c > new file mode 100644 > index 0000000..a8e995f > --- /dev/null > +++ b/sound/soc/bcm2708/bcm2708-i2s.c > @@ -0,0 +1,964 @@ [...] > +static int bcm2708_i2s_startup(struct snd_pcm_substream *substream, > + struct snd_soc_dai *dai) > +{ > + struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai); > + > + if (!dev->first_stream) { > + dev->first_stream = substream; > + > + /* should this still be running stop it */ > + bcm2708_i2s_stop_clock(dev); > + > + /* enable PCM block */ > + bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG, BCM2708_I2S_EN); > + > + /* > + * Disable STBY > + * Requires at least 4 PCM clock cycles to take effect > + */ > + bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG, > + BCM2708_I2S_STBY); > + } else { > + struct snd_pcm_runtime *first_runtime = > + dev->first_stream->runtime; > + > + /* > + * This is the second stream open, so we need to impose > + * sample size and sampling rate constraints. > + * This is because frame length and clock cannot be specified > + * seperately. > + * > + * Note that this can cause a race condition if the > + * second stream is opened before the first stream is > + * fully initialized. We provide some protection by > + * checking to make sure the first stream is > + * initialized, but it's not perfect. ALSA sometimes > + * re-initializes the driver with a different sample > + * rate or size. If the second stream is opened > + * before the first stream has received its final > + * parameters, then the second stream may be > + * constrained to the wrong sample rate or size. > + * > + * We will continue in case of failure and recheck the > + * constraint in hw_params. > + */ > + if (!first_runtime->format) { > + dev_err(substream->pcm->card->dev, > + "Set format in %s stream first! " > + "Initialization may fail.\n", > + substream->stream == > + SNDRV_PCM_STREAM_PLAYBACK > + ? "capture" : "playback"); > + } else { > + snd_pcm_hw_constraint_minmax(substream->runtime, > + SNDRV_PCM_HW_PARAM_FORMAT, > + first_runtime->format, > + first_runtime->format); > + } > + > + if (!first_runtime->rate) { > + dev_err(substream->pcm->card->dev, > + "Set sampling rate in %s stream first! " > + "Initialization may fail!\n", > + substream->stream == > + SNDRV_PCM_STREAM_PLAYBACK > + ? "capture" : "playback"); > + } else { > + snd_pcm_hw_constraint_minmax(substream->runtime, > + SNDRV_PCM_HW_PARAM_RATE, > + first_runtime->rate, > + first_runtime->rate); > + }
Setting the symmetric_rates lets the core take care of setting the proper constraints on the rate. It probably makes sense to also add a symmetric_formats since this isn't the only driver that has the requirement that the formats for playback and capture match.
> + > + dev->second_stream = substream; > + } > + > + snd_soc_dai_set_dma_data(dai, substream, > + &dev->dma_params[substream->stream]); > + > + return 0; > +} > + > +static void bcm2708_i2s_shutdown(struct snd_pcm_substream *substream, > + struct snd_soc_dai *dai) > +{ > + struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai); > + > + bcm2708_i2s_stop(dev, substream); > + > + if (dev->first_stream == substream) > + dev->first_stream = dev->second_stream; > + > + dev->second_stream = NULL; > + > + /* If both streams are stopped, disable module and clock */ > + if (!dev->first_stream) { > + /* Disable the module */ > + bcm2708_i2s_clear_bits(dev, BCM2708_I2S_CS_A_REG, > + BCM2708_I2S_EN); > + > + /* > + * Stopping clock is necessary, because stop does > + * not stop the clock when SND_SOC_DAIFMT_CONT > + */ > + bcm2708_i2s_stop_clock(dev); > + } > +} [...] > diff --git a/sound/soc/bcm2708/bcm2708-pcm.c b/sound/soc/bcm2708/bcm2708-pcm.c > new file mode 100644 > index 0000000..4b3e688 > --- /dev/null > +++ b/sound/soc/bcm2708/bcm2708-pcm.c > @@ -0,0 +1,303 @@
I think you should be able to remove the bulk of this driver by using the generic PCM dmaengine driver.
[...] > + > +#include "bcm2708-pcm.h" > + > +static const struct snd_pcm_hardware bcm2708_pcm_hardware = { > + .info = SNDRV_PCM_INFO_MMAP | > + SNDRV_PCM_INFO_MMAP_VALID | > + SNDRV_PCM_INFO_INTERLEAVED | > + SNDRV_PCM_INFO_PAUSE | > + SNDRV_PCM_INFO_RESUME | > + SNDRV_PCM_INFO_JOINT_DUPLEX | > + SNDRV_PCM_INFO_NO_PERIOD_WAKEUP,
I don't think you actually support the last one, and neither pause and resume are supported.
> + .formats = SNDRV_PCM_FMTBIT_S16_LE | > + SNDRV_PCM_FMTBIT_S32_LE, > + .period_bytes_min = 32, > + .period_bytes_max = 64 * 1024, > + .periods_min = 2, > + .periods_max = 255, > + .buffer_bytes_max = 128 * 1024, > +}; > + [...]
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