[alsa-devel] [PATCH 3/3] ALSA: ASoC: cs4271: add optional soft reset workaround
zonque at gmail.com
Wed Dec 5 14:59:37 CET 2012
On 02.12.2012 05:02, Mark Brown wrote:
> On Fri, Nov 30, 2012 at 11:28:57AM +0100, Daniel Mack wrote:
>> + Note that this is not needed in case the clocks are stable
>> + throughout the entire runtime of the codec.
> That's really quite rare for embeded systems, though - normally at least
> the LRCLK is going to be enabled only when there's audio.
I agree, but I don't know which system the original driver was written
for. As it seems to work there, I didn't want to unconditionally
introduce this new reset command.
>> +static int cs4271_startup(struct snd_pcm_substream *subs,
>> + struct snd_soc_dai *codec_dai)
>> + int ret;
>> + struct snd_soc_codec *codec = codec_dai->codec;
>> + struct cs4271_private *cs4271 = snd_soc_codec_get_drvdata(codec);
>> + if (!cs4271->enable_soft_reset)
>> + return 0;
>> + /*
>> + * Put the codec in soft reset and back again in case it's not
>> + * currently streaming data. This way of bringing the codec in
>> + * sync to the current clocks is not explicitly documented in
>> + * the data sheet, but it seems to work fine.
>> + */
> Since startup() is called before hw_params() you might well find even an
> active LRCLK is going to change underneath the driver here...
Hmm ok, so you're saying this quirk should go in hwparams() then?
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