Unverified Commit 6cd249cf authored by Tzung-Bi Shih's avatar Tzung-Bi Shih Committed by Mark Brown
Browse files

ASoC: max98357a: use mdelay for sdmode-delay 



max98357a_daiops_trigger() is possible to be called in atomic context if
the .nonatomic flag is equal to 0 in the DAI links.

When cancel_delayed_work_sync() in max98357a_daiops_trigger() is called
in atomic context, kernel emits the following message: "BUG: sleeping
function called from invalid context".

According to the DT binding document, value less than or equal to 5ms of
sdmod-delay should be sufficient to avoid the pop noise.  Use mdelay
(i.e. busy loop) for such low delay should be acceptable.

Fixes: cec5b01f ("ASoC: max98357a: avoid speaker pop when playback
startup")

Signed-off-by: default avatarTzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20190708141901.68797-1-tzungbi@google.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 87a6fe80

sound/soc/codecs/max98357a.c

+4 −21
Original line number Diff line number Diff line
@@ -20,20 +20,10 @@ 
#include <sound/soc-dapm.h>



struct max98357a_priv {

	struct delayed_work enable_sdmode_work;

	struct gpio_desc *sdmode;

	unsigned int sdmode_delay;

};



static void max98357a_enable_sdmode_work(struct work_struct *work)

{

	struct max98357a_priv *max98357a =

	container_of(work, struct max98357a_priv,

			enable_sdmode_work.work);



	gpiod_set_value(max98357a->sdmode, 1);

}



static int max98357a_daiops_trigger(struct snd_pcm_substream *substream,

		int cmd, struct snd_soc_dai *dai)

{
@@ -46,14 +36,12 @@ static int max98357a_daiops_trigger(struct snd_pcm_substream *substream, 
	case SNDRV_PCM_TRIGGER_START:

	case SNDRV_PCM_TRIGGER_RESUME:

	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:

		queue_delayed_work(system_power_efficient_wq,

				&max98357a->enable_sdmode_work,

				msecs_to_jiffies(max98357a->sdmode_delay));

		mdelay(max98357a->sdmode_delay);

		gpiod_set_value(max98357a->sdmode, 1);

		break;

	case SNDRV_PCM_TRIGGER_STOP:

	case SNDRV_PCM_TRIGGER_SUSPEND:

	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:

		cancel_delayed_work_sync(&max98357a->enable_sdmode_work);

		gpiod_set_value(max98357a->sdmode, 0);

		break;

	}
@@ -112,30 +100,25 @@ static int max98357a_platform_probe(struct platform_device *pdev) 
	int ret;



	max98357a = devm_kzalloc(&pdev->dev, sizeof(*max98357a), GFP_KERNEL);



	if (!max98357a)

		return -ENOMEM;



	max98357a->sdmode = devm_gpiod_get_optional(&pdev->dev,

				"sdmode", GPIOD_OUT_LOW);



	if (IS_ERR(max98357a->sdmode))

		return PTR_ERR(max98357a->sdmode);



	ret = device_property_read_u32(&pdev->dev, "sdmode-delay",

					&max98357a->sdmode_delay);



	if (ret) {

		max98357a->sdmode_delay = 0;

		dev_dbg(&pdev->dev,

			"no optional property 'sdmode-delay' found, default: no delay\n");

			"no optional property 'sdmode-delay' found, "

			"default: no delay\n");

	}



	dev_set_drvdata(&pdev->dev, max98357a);



	INIT_DELAYED_WORK(&max98357a->enable_sdmode_work,

				max98357a_enable_sdmode_work);



	return devm_snd_soc_register_component(&pdev->dev,

			&max98357a_component_driver,

			&max98357a_dai_driver, 1);

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