linux-kernel - Re: [PATCH] ASoC: pcm512x: Mend accesses to the I2S_1 and I2S

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Date:   Tue, 21 Sep 2021 10:48:01 +0200
From:   Peter Rosin <peda@...ntia.se>
To:     Péter Ujfalusi <peter.ujfalusi@...il.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Takashi Iwai <tiwai@...e.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Kirill Marinushkin <kmarinushkin@...dec.com>,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH] ASoC: pcm512x: Mend accesses to the I2S_1 and I2S_2
 registers

On 2021-09-21 10:10, Peter Rosin wrote:
>>> Can you try the attached patch w/o without the defaults for i2s_1/2?
>>> Not even compile tested...
>>
>> [added a couple of underscores]
>>
>> I get this early during boot/probe
>> [    1.506291] pcm512x 0-004c: pcm512x_set_fmt: failed to read I2S_1: -16
>> [    1.512905] pcm512x 0-004c: pcm512x_set_fmt: failed to read PLL_EN: -16
>> [    1.519517] pcm512x 0-004c: Failed to set data format: -16
>> [    1.525045] pcm512x 0-004c: Failed to set data offset: -16
>>
>> and then this later, triggered from userspace when an app opens
>> the device
>> [   14.620344] pcm512x 0-004c: pcm512x_hw_params: I2S_1: 0x2
>>
>> So, reading *can* work.
> 
> I added some traces and verified that accesses to I2S_1/2 fail (as do
> PLL_EN accesses) when the chip is in Powerdown mode (pcm512x_suspend
> has set the RQPD bit in the POWER register), which it is when
> pcm512x_set_fmt runs. During pcm512x_hw_params the chip is in Standby
> mode instead (pcm512x_resume has cleared the RQPD bit, but the RQST
> bit is set).
> 
> So, my patch seems wrong, and the I2S_1/2 accesses instead need to
> move to some point where the chip is not in Powerdown mode.
> 
> Or, is the problem that pcm512x_set_fmt is called while the codec is
> suspended and the chip thus is in Powerdown mode? Because, that
> seems problematic to me?

Ok, so the attached works for me as well. But I don't know if it's
appropriate to resume/suspend like that?

Cheers,
Peter

View attachment "0001-ASoC-pcm512x-Mend-accesses-to-the-I2S_1-and-I2S_2-re.patch" of type "text/plain" (1778 bytes)