linux-kernel - Re: [PATCHv4 7/9] ASoC: fsl-asoc-card: add DT clock "cpu

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Date: Thu, 16 May 2024 13:13:19 +0100
From: Mark Brown <broonie@...nel.org>
To: Elinor Montmasson <elinor.montmasson@...oirfairelinux.com>
Cc: Liam Girdwood <lgirdwood@...il.com>, Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Shengjiu Wang <shengjiu.wang@...il.com>,
	Xiubo Li <Xiubo.Lee@...il.com>, Fabio Estevam <festevam@...il.com>,
	Nicolin Chen <nicoleotsuka@...il.com>,
	Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
	linux-sound@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, alsa-devel@...a-project.org,
	linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCHv4 7/9] ASoC: fsl-asoc-card: add DT clock "cpu_sysclk"
 with generic codec

On Wed, May 15, 2024 at 03:54:09PM +0200, Elinor Montmasson wrote:

> Add an optional DT clock "cpu_sysclk" to get the CPU DAI system-clock
> frequency when using the generic codec.
> It is set for both Tx and Rx.
> The way the frequency value is used is up to the CPU DAI driver
> implementation.

> +		struct clk *cpu_sysclk = clk_get(&pdev->dev, "cpu_sysclk");
> +		if (!IS_ERR(cpu_sysclk)) {
> +			priv->cpu_priv.sysclk_freq[TX] = clk_get_rate(cpu_sysclk);
> +			priv->cpu_priv.sysclk_freq[RX] = priv->cpu_priv.sysclk_freq[TX];
> +			clk_put(cpu_sysclk);
> +		}

I don't really understand the goal here - this is just reading whatever
frequency happens to be set in the hardware when the driver starts up
which if nothing else seems rather fragile?

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