>>> +static int cs42l42_sdw_dai_startup(struct snd_pcm_substream *substream, >>> + struct snd_soc_dai *dai) >>> +{ >>> + struct cs42l42_private *cs42l42 = >>> snd_soc_component_get_drvdata(dai->component); >>> + >>> + if (!cs42l42->init_done) >>> + return -ENODEV; >> >> Can this happen? IIRC the ASoC framework would use >> pm_runtime_resume_and_get() before .startup, which would guarantee that >> the device is initialized, no? >> > > Yes, this can happen. Because of the way that the SoundWire enumeration > was implemented in the core code, it isn't a probe event so we cannot > call snd_soc_register_component() on enumeration because -EPROBE_DEFER > wouldn't be handled. So the snd_soc_register_component() must be called > from probe(). This leaves a limbo situation where we've registered the > driver but in fact don't yet have any hardware. ALSA/ASoC doesn't know > that we've registered before we are functional so they are happy to > go ahead and try to use the soundcard. If for some reason the hardware > failed to enumerate we can get here without having enumerated. Humm, yes, but you've also made the regmap cache-only, so is there really a problem? FWIW I don't see a startup callback in any other codec driver. It may be wrong but it's also a sign that this isn't a problem we've seen so far on existing Intel-based platforms. > >>> + >>> + return 0; >>> +} >>> + >>> +static int cs42l42_sdw_dai_hw_params(struct snd_pcm_substream >>> *substream, >>> + struct snd_pcm_hw_params *params, >>> + struct snd_soc_dai *dai) >>> +{ >>> + struct cs42l42_private *cs42l42 = >>> snd_soc_component_get_drvdata(dai->component); >>> + struct sdw_stream_runtime *sdw_stream = >>> snd_soc_dai_get_dma_data(dai, substream); >>> + struct sdw_stream_config stream_config = {0}; >>> + struct sdw_port_config port_config = {0}; >>> + int ret; >>> + >>> + if (!sdw_stream) >>> + return -EINVAL; >>> + >>> + /* Needed for PLL configuration when we are notified of new bus >>> config */ >>> + cs42l42->sample_rate = params_rate(params); >> >> wouldn't it be better to check if the sample_rate is supported by the >> PLL here, instead of in the .prepare step ... >> > It depends on the soundwire bus clock. We need to know both to determine > whether they are valid. IFF we can assume that the call to > sdw_stream_add_slave() will always invoke the bus_config() callback we > can call cs42l42_pll_config() from cs42l42_sdw_bus_config() and return > an error from cs42l42_sdw_bus_config() if the {swire_clk, sample_rate} > pair isn't valid. You lost me here. Are you saying the soundwire bus clock is only known in the prepare stage? >>> +static int cs42l42_sdw_dai_set_sdw_stream(struct snd_soc_dai *dai, >>> void *sdw_stream, >>> + int direction) >>> +{ >>> + if (!sdw_stream) >>> + return 0; >>> + >>> + if (direction == SNDRV_PCM_STREAM_PLAYBACK) >>> + dai->playback_dma_data = sdw_stream; >>> + else >>> + dai->capture_dma_data = sdw_stream; >>> + >>> + return 0; >> >> Humm, this is interesting, you are not using the sdw_stream_data that >> all other codecs use, but in hindsight I have no idea why we allocate >> something to only store a pointer. >> > > Indeed. I can see no reason to wrap this pointer in another struct when > we can store the pointer direct so I dropped the wrapper struct. I'll see if we can simplify the other codec drivers. >>> +static int cs42l42_sdw_update_status(struct sdw_slave *peripheral, >>> + enum sdw_slave_status status);s >>> +{ >>> + struct cs42l42_private *cs42l42 = >>> dev_get_drvdata(&peripheral->dev); >>> + >>> + switch (status) { >>> + case SDW_SLAVE_ATTACHED: >>> + dev_dbg(cs42l42->dev, "ATTACHED\n"); >>> + if (!cs42l42->init_done) >>> + cs42l42_sdw_init(peripheral); >> >> unclear to me what happens is the bus suspends, how would you redo the >> init? >> > > We don't need to re-run the init(). A regcache_sync() will restore > settings. ah, interesting. Other codec drivers play with specific registers that aren't in regmap. There's also headset calibration that's done differently in the first init or later.