linux-kernel - Re: [alsa-devel] [PATCH] ASoC: wm8994: Manage wm8994's MCLK in codec driver

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Message-ID: <20150312113945.GO28806@sirena.org.uk>
Date:	Thu, 12 Mar 2015 11:39:45 +0000
From:	Mark Brown <broonie@...nel.org>
To:	Inha Song <ideal.song@...sung.com>
Cc:	alsa-devel@...a-project.org, patches@...nsource.wolfsonmicro.com,
	linux-kernel@...r.kernel.org, ckeepax@...nsource.wolfsonmicro.com,
	nikesh@...nsource.wolfsonmicro.com, lars@...afoo.de,
	lgirdwood@...il.com, perex@...ex.cz, tiwai@...e.de,
	Li.Xiubo@...escale.com, sachin.kamat@...sung.com,
	cw00.choi@...sung.com
Subject: Re: [alsa-devel] [PATCH] ASoC: wm8994: Manage wm8994's MCLK in codec
 driver

On Thu, Mar 12, 2015 at 11:49:39AM +0900, Inha Song wrote:

> -		if (codec->dapm.bias_level == SND_SOC_BIAS_STANDBY)
> +		if (codec->dapm.bias_level == SND_SOC_BIAS_STANDBY) {
> +			for (i = 0; i < ARRAY_SIZE(wm8994->clk_mclk); i++) {
> +				if (!IS_ERR(wm8994->clk_mclk[i]))
> +					clk_prepare_enable(wm8994->clk_mclk[i]);
> +			}

This isn't checking return values.  It's also enabling both clocks all
the time which isn't always going to be what's desired - it may result
in an expensive high frequency reference clock being enabled when only
a 32kHz clock is needed for example.  That doesn't seem desirable.

>  			active_reference(codec);

Should this perhaps be being done in active_reference instead?

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