Re: [alsa-devel] Is that reasonable to support pinctrl PM in ASoC core?

25 Oct 2013


      On Thu, Oct 24, 2013 at 07:07:43PM +0800, Nicolin Chen wrote:
...
Hi all,
It's quite popular that more drivers are using pinctrl PM, for example:
(Documentation/devicetree/bindings/arm/primecell.txt). Just like what
runtime PM does, it would de-active and en-active pin group depending
on whether it's being used or not.
And I think this pinctrl PM might be also beneficial to cpu dai drivers
since they might have actual pins, and they can hypnotize/wake them up
along with runtime PM:
@@ -183,6 +183,7 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)
   struct snd_soc_dai_driver *codec_dai_drv = codec_dai->driver;
   int ret = 0;

  pinctrl_pm_select_default_state(cpu_dai->dev);

pm_runtime_get_sync(cpu_dai->dev);
 pm_runtime_get_sync(codec_dai->dev);
 pm_runtime_get_sync(platform->dev);     



As pinctrl PM is also reference counted and would return 0 if there
is no pinctrl settings, this would not break current ASoC subsystem
and any cpu dai driver.
This was a mistake that pinctrl PM seems to be not reference counting.
So I have to correct it here.
And I'm sorry if I misguided anyone.
Nicolin Chen
...
So I just want to ask if it's reasonable to add it. Or another one:
is there anything similar to sleep pins? Although I've searched the
whole ./sound directory, it seems no drivers under it is using this
pinctrl PM.
Best regards,
Nicolin Chen

    