linux-kernel - Re: [PATCH 2/2] ASoC: wm8994: Ensure the device is resumed in wm89xx_mic

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Date:   Fri, 28 Aug 2020 08:48:12 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Sylwester Nawrocki <s.nawrocki@...sung.com>
Cc:     broonie@...nel.org, lgirdwood@...il.com,
        ckeepax@...nsource.cirrus.com, patches@...nsource.cirrus.com,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        m.szyprowski@...sung.com, b.zolnierkie@...sung.com
Subject: Re: [PATCH 2/2] ASoC: wm8994: Ensure the device is resumed in
 wm89xx_mic_detect functions

On Thu, Aug 27, 2020 at 07:33:57PM +0200, Sylwester Nawrocki wrote:
> When the wm8958_mic_detect, wm8994_mic_detect functions get called from
> the machine driver, e.g. from the card's late_probe() callback, the CODEC
> device may be PM runtime suspended and any regmap writes have no effect.
> Add PM runtime calls to these functions to ensure the device registers
> are updated as expected.
> This suppresses an error during boot
> "wm8994-codec: ASoC: error at snd_soc_component_update_bits on wm8994-codec"
> caused by the regmap access error due to the cache_only flag being set.
> 
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
> ---
>  sound/soc/codecs/wm8994.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
> index b3ba053..fc9ea19 100644
> --- a/sound/soc/codecs/wm8994.c
> +++ b/sound/soc/codecs/wm8994.c
> @@ -3514,6 +3514,8 @@ int wm8994_mic_detect(struct snd_soc_component *component, struct snd_soc_jack *
>  		return -EINVAL;
>  	}
>  
> +	pm_runtime_get_sync(component->dev);

The driver enables PM runtime unconditionally so you should probably
handle the error code here. I know that driver does not do it in other
cases but it should not be a reason to multiple this pattern... unless
it really does not matter as there are no runtime PM ops?

Best regards,
Krzysztof