[PATCH 2/2] ASoC: Intel: boards: use software node API in Atom boards

[Pierre-Louis Bossart]

>>   static int snd_byt_cht_es8316_mc_remove(struct platform_device *pdev)
>> @@ -617,6 +634,8 @@ static int snd_byt_cht_es8316_mc_remove(struct platform_device *pdev)
>>   	struct byt_cht_es8316_private *priv = snd_soc_card_get_drvdata(card);
>>   
>>   	gpiod_put(priv->speaker_en_gpio);
>> +	device_remove_software_node(priv->codec_dev);
> 
> This is a problem, nothing guarantees codec_dev not going away before
> snd_byt_cht_es8316_mc_remove() runs. Although the only thing which I can come up
> with where this happens is unbinding the i2c-controller driver I still would like
> us to take this scenario into account.

Is this possible really? the codec driver will register a component 
that's used by the ASoC card, I was assuming that there was some sort of 
reference count already to prevent this unbinding from happening.

> I think it would be better to use device_create_managed_software_node() to tie
> the lifetime of the swnode to the lifetime of the device, this also removes
> the need for all the goto err cases (and introducing a remove function in
> the bytcr_rt5640.c case).
> 
> This does mean that we could end up calling device_create_managed_software_node()
> on the same device twice, when the machine driver gets unbound + rebound, but
> that is an already existing issue with our current device_add_properties() usage.
> 
> We could fix this (in a separate commit since it is an already existing issue)
> by adding a PROPERTY_ENTRY_BOOL("cht_es8316,swnode-created") property to the
> properties and checking for that being set with
> device_property_read_bool(codec, "cht_es8316,swnode-created")
> 
> Or we could move the device_put(codec_dev) to snd_byt_cht_es8316_mc_remove().

that sounds like a better plan if you want to manage explicit 
dependencies - regardless of how which API is used to manage properties.