linux-kernel - Re: [PATCH] ASoC: AMD: Add a fix voltage regulator for DA7219 and ADAU7002

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Date:   Mon, 23 Jul 2018 10:56:44 +0530
From:   "Agrawal, Akshu" <Akshu.Agrawal@....com>
To:     Mark Brown <broonie@...nel.org>
Cc:     djkurtz@...omium.org, Alexander.Deucher@....com,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Dylan Reid <dgreid@...omium.org>,
        "Mukunda, Vijendar" <Vijendar.Mukunda@....com>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        Wei Yongjun <weiyongjun1@...wei.com>,
        "moderated list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEM..." 
        <alsa-devel@...a-project.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ASoC: AMD: Add a fix voltage regulator for DA7219 and
 ADAU7002



On 7/20/2018 5:48 PM, Mark Brown wrote:
> On Fri, Jul 20, 2018 at 02:38:11PM +0800, Akshu Agrawal wrote:
> 
>>  static int cz_probe(struct platform_device *pdev)
>>  {
>>  	int ret;
>>  	struct snd_soc_card *card;
>>  	struct acp_platform_info *machine;
>> +	static bool regulators_registered;
>> +
>> +	if (!regulators_registered) {
>> +		ret = platform_device_register(&acp_da7219_regulator);
>> +		if (ret) {
>> +			dev_err(&pdev->dev, "Failed to register regulator: %d\n",
>> +				ret);
>> +			return ret;
>> +		}
>> +		regulators_registered = true;
>> +	}
> 
> You should be unregistering the regulator in your remove function, not
> doing this hack here.  I'd also expect to see the card made the parent
> of the device that gets registered.
> 

This approach shows inconsistencies and in some boot cycles da7219 fails
to get regulator. Form the logs (below) it shows time gap between the
time we call “platform_device_register(&acp_da7219_regulator);” and when
the regulator actually gets registered.

[   12.594237] regulator registered
**print after calling “platform_device_register(&acp_da7219_regulator);”
...
[   13.583689] da7219 i2c-DLGS7219:00: i2c-DLGS7219:00 supply VDD not
found, using dummy regulator
[   13.593818] da7219 i2c-DLGS7219:00: i2c-DLGS7219:00 supply VDDMIC not
found, using dummy regulator
[   13.603242] da7219 i2c-DLGS7219:00: i2c-DLGS7219:00 supply VDDIO not
found, using dummy regulator
[   13.612626] da7219 i2c-DLGS7219:00: Invalid VDDIO voltage
**Above DA7219 gets probed and does not find the regulator**
...
[   13.750894] reg_fixed_voltage_probe: Supply -> reg-fixed-1.8V
[   13.766746] reg-fixed-1.8V supplying 1800000uV
**Regulator actually gets registered**

Alternate and consistent approach to this is pushed by Daniel here:
https://patchwork.kernel.org/patch/10539485/

Thanks,
Akshu