linux-kernel - Re: [PATCH v3] ASoC: amd: add support for rt5682 codec in machine driver

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Date:   Mon, 15 Mar 2021 11:00:57 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Vijendar Mukunda <Vijendar.Mukunda@....com>, broonie@...nel.org,
        alsa-devel@...a-project.org
Cc:     Alexander.Deucher@....com, Murali-krishna.Vemuri@....com,
        Virendra-Pratap.Arya@....com, Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Ravulapati Vishnu vardhan rao 
        <Vishnuvardhanrao.Ravulapati@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        Chuhong Yuan <hslester96@...il.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] ASoC: amd: add support for rt5682 codec in machine
 driver


> +static int rt5682_clk_enable(struct snd_pcm_substream *substream)
> +{
> +	int ret;
> +	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
> +
> +	/*
> +	 * Set wclk to 48000 because the rate constraint of this driver is
> +	 * 48000. ADAU7002 spec: "The ADAU7002 requires a BCLK rate that is
> +	 * minimum of 64x the LRCLK sample rate." RT5682 is the only clk
> +	 * source so for all codecs we have to limit bclk to 64X lrclk.
> +	 */
> +	clk_set_rate(rt5682_dai_wclk, 48000);
> +	clk_set_rate(rt5682_dai_bclk, 48000 * 64);
> +	ret = clk_prepare_enable(rt5682_dai_bclk);
> +	if (ret < 0) {
> +		dev_err(rtd->dev, "can't enable master clock %d\n", ret);
> +		return ret;
> +	}
> +	return ret;
> +}

Out of curiosity, is there a reason why you use clk_prepare_enable() for 
the bclk but not for the wclk?