linux-kernel - Re: [PATCH 3/6] ASoC: fsl_micfil: Add support for PLL switch at runtime

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Message-ID: <Yr1842e42P4piYnE@sirena.org.uk>
Date:   Thu, 30 Jun 2022 11:37:23 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Shengjiu Wang <shengjiu.wang@....com>
Cc:     nicoleotsuka@...il.com, Xiubo.Lee@...il.com, festevam@...il.com,
        shengjiu.wang@...il.com, lgirdwood@...il.com, perex@...ex.cz,
        tiwai@...e.com, alsa-devel@...a-project.org, robh+dt@...nel.org,
        krzk+dt@...nel.org, devicetree@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/6] ASoC: fsl_micfil: Add support for PLL switch at
 runtime

On Thu, Jun 30, 2022 at 01:39:11PM +0800, Shengjiu Wang wrote:

> +static int fsl_micfil_reparent_rootclk(struct fsl_micfil *micfil, unsigned int sample_rate)
> +{
> +	struct device *dev = &micfil->pdev->dev;
> +	u64 ratio = sample_rate;
> +	struct clk *clk;
> +	int ret;
> +
> +	/* Reparent clock if required condition is true */
> +	if (!micfil->pll8k_clk || !micfil->pll11k_clk)
> +		return 0;
> +
> +	ratio = do_div(ratio, 8000) ? CLK_11K_FREQ : CLK_8K_FREQ;
> +
> +	/* Get root clock */
> +	clk = micfil->mclk;
> +	if (IS_ERR_OR_NULL(clk)) {
> +		dev_err(dev, "no mclk clock in devicetree\n");
> +		return PTR_ERR(clk);
> +	}
> +
> +	/* Disable clock first, for it was enabled by pm_runtime */
> +	clk_disable_unprepare(clk);
> +	fsl_asoc_reparent_pll_clocks(dev, clk, micfil->pll8k_clk,
> +				     micfil->pll11k_clk, ratio);
> +	ret = clk_prepare_enable(clk);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}

Seems like more of this logic could be factored out into the reparent
function if the target sample rate is passed in?

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