linux-kernel - Re: [PATCH v3] ASoC: fsl: imx-wm8962: Grant hw

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Message-ID: <20131217225002.GR28455@sirena.org.uk>
Date:	Tue, 17 Dec 2013 22:50:02 +0000
From:	Mark Brown <broonie@...nel.org>
To:	Nicolin Chen <Guangyu.Chen@...escale.com>
Cc:	lgirdwood@...il.com, alsa-devel@...a-project.org, tiwai@...e.de,
	perex@...ex.cz, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] ASoC: fsl: imx-wm8962: Grant hw_params/free()
 permission to control FLL

On Thu, Dec 12, 2013 at 05:59:28PM +0800, Nicolin Chen wrote:

> +	mask = WM8962_MIXINL_TO_HPMIXL_MASK | WM8962_MIXINR_TO_HPMIXL_MASK |
> +		WM8962_IN4L_TO_HPMIXL_MASK | WM8962_IN4R_TO_HPMIXL_MASK;
> +	bypass |= snd_soc_read(codec, WM8962_HEADPHONE_MIXER_1) & mask;
> +	bypass |= snd_soc_read(codec, WM8962_HEADPHONE_MIXER_2) & mask;
> +	bypass |= snd_soc_read(codec, WM8962_SPEAKER_MIXER_1) & mask;
> +	bypass |= snd_soc_read(codec, WM8962_SPEAKER_MIXER_2) & mask;
> +
> +	/* Don't diable FLL if running multi-substreams or analogue bypass */
> +	if (codec_dai->active != 1 || bypass)
> +		return 0;

I don't think this works with the power down delay we do on playback -
the DAI will go inactive when closed but we'll still have the CODEC
active and using its clocks until the power down time has elapsed if
it's a playback DAI.  Trying to reclock the device while active is at
best risky, even if it's muted.

I do think refcounting from both here and the bias level changes is
going to be the most robust thing, that'd also avoid the need to peer
into the CODEC register map.

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