Re: ASoC: TLV320AIC3x: Adding additional functionality for 3106 with [Patch] for discuss

[Timur Karaldin <karaldin@mcsplus.ru>]

Hi Peter!

17.03.2016 12:26, Peter Ujfalusi пишет:
>> Ok, now it's much more clear for me.
>> Another question is register behaviour during soft reset. There is
>> "aic3x_set_power" handle. In this handle kernel makes SOFT_RESET, markes cache
>> as dirty, then power down the codec for handle power down request.
>> But as I could see main volumes like "HP DAC" and "PCM" stores values between
>> close and open in mixer and I could not see any code to handle it. On the
>> other hand my controls do not save states, as you mentioned because of
>> SOFT_RESET, could you explain such different behaviour?

> All cached registers are going to be restored after power on with exception of
> volatile registers. You need to restore the bits in a volatile registers in
> the driver.
>
I'm very close to patch v2,  but I have some problems with 
misunderstanding the key moment with dapm handler 
snd_soc_dapm_put_volsw_aic3x I think.
I successfuly wrote put/get handlers for DOUBLE_R_EXT_TLV and 
SINGLE_EXT_TLV volume controls using snd_kcontrol_chip and 
snd_soc_codec_get_drvdata function for accessing codec's private data. 
It's work. But any attempts in snd_soc_dapm_put_volsw_aic3x to get priv 
data aix3x_priv* make kernel error:  Unable to handle kernel NULL 
pointer dereference at virtual address 0000009e. If I remove 
snd_soc_codec_get_drvdata call and accessing to cached regs it's become 
normal again.
Currently I use kernel 3.15 and there is some example in wm8903.c

static int wm8903_class_w_put(struct snd_kcontrol *kcontrol,
                               struct snd_ctl_elem_value *ucontrol)
{
          struct snd_soc_codec *codec = 
snd_soc_dapm_kcontrol_codec(kcontrol);
          struct wm8903_priv *wm8903 = snd_soc_codec_get_drvdata(codec);
         ...
and it's look ok, and I hope it's working, but not good for me in 
snd_soc_dapm_put_volsw_aic3x handler.
Do you have any idea or any tips I should keep in mind, when working in 
DAPM context?



Cheers, Tim
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