linux-kernel - Re: [PATCH v2] ASoC: mxs-saif: add mclk enable/disable ops

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Message-ID: <20170123190701.hva43ac4ceo6xxla@sirena.org.uk>
Date:   Mon, 23 Jan 2017 19:07:01 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Mans Rullgard <mans@...sr.com>
Cc:     alsa-devel@...a-project.org, Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, linux-kernel@...r.kernel.org,
        Jörg Krause <joerg.krause@...edded.rocks>
Subject: Re: [PATCH v2] ASoC: mxs-saif: add mclk enable/disable ops

On Thu, Dec 22, 2016 at 04:49:26PM +0000, Mans Rullgard wrote:

>  int mxs_saif_put_mclk(unsigned int saif_id)
>  {
> -	struct mxs_saif *saif = mxs_saif[saif_id];
> -	u32 stat;
> +	struct clk *clk;
>  
> -	if (!saif)
> -		return -EINVAL;
> +	clk = clk_get(NULL, "mxs_saif_mclk");
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);

So, this *is* an in place refactoring but it's only half done in that
we don't have any followup patches that move the clk_get() to device
probe where it should be.

> +static void mxs_saif_mclk_disable(struct clk_hw *hw)
> +{
> +	struct mxs_saif *saif = to_mxs_saif(hw);
> +
> +	if (!saif->ongoing)
> +		__raw_writel(BM_SAIF_CTRL_RUN,
> +			     saif->base + SAIF_CTRL + MXS_CLR_ADDR);
> +
> +	saif->mclk_in_use = 0;
> +}

We silently ignore disables if the clock is in use?  That seems error
prone.  I'd expect us to at least warn in that case.

> +static unsigned long mxs_saif_mclk_recalc_rate(struct clk_hw *hw,
> +					       unsigned long parent_rate)
> +{
> +	return clk_divider_ops.recalc_rate(hw, parent_rate);
> +}

Can't we just assign these ops directly?  Having to write wrapper
functions like this looks like we're doing something wrong here.

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