linux-kernel - Re: [RFT v2] mfd: exynos-lpass: Handle return value of clk_prepare

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Message-ID: <20170810060140.GA3625@kozik-book>
Date:   Thu, 10 Aug 2017 08:01:40 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Arvind Yadav <arvind.yadav.cs@...il.com>
Cc:     lee.jones@...aro.org, kgene@...nel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Andi Shyti <andi.shyti@...sung.com>
Subject: Re: [RFT v2] mfd: exynos-lpass: Handle return value of
 clk_prepare_enable

On Wed, Aug 09, 2017 at 10:18:10AM +0530, Arvind Yadav wrote:
> clk_prepare_enable() can fail here and we must check its return value.
> we must call pm_runtime_disable() and pm_runtime_set_suspended(),
> If exynos_lpass_probe is not successful.
> 
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@...il.com>
> ---
> changes in v2:
>              added regmap_exit(lpass->top) and blank line before return.
> 
>  drivers/mfd/exynos-lpass.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
>

For me looks ok although this requires testing and I do not have
Exynos with LPASS (e.g. Exynos5433). Maybe folks from Samsung (Polish
R&D or HQ as they are working on it) could help (Cced).

Best regards,
Krzysztof

> diff --git a/drivers/mfd/exynos-lpass.c b/drivers/mfd/exynos-lpass.c
> index ca829f8..1ab7210 100644
> --- a/drivers/mfd/exynos-lpass.c
> +++ b/drivers/mfd/exynos-lpass.c
> @@ -73,9 +73,13 @@ static void exynos_lpass_core_sw_reset(struct exynos_lpass *lpass, int mask)
>  	regmap_write(lpass->top, SFR_LPASS_CORE_SW_RESET, val);
>  }
>  
> -static void exynos_lpass_enable(struct exynos_lpass *lpass)
> +static int exynos_lpass_enable(struct exynos_lpass *lpass)
>  {
> -	clk_prepare_enable(lpass->sfr0_clk);
> +	int ret;
> +
> +	ret = clk_prepare_enable(lpass->sfr0_clk);
> +	if (ret)
> +		return ret;
>  
>  	/* Unmask SFR, DMA and I2S interrupt */
>  	regmap_write(lpass->top, SFR_LPASS_INTR_CA5_MASK,
> @@ -87,6 +91,8 @@ static void exynos_lpass_enable(struct exynos_lpass *lpass)
>  	exynos_lpass_core_sw_reset(lpass, LPASS_I2S_SW_RESET);
>  	exynos_lpass_core_sw_reset(lpass, LPASS_DMA_SW_RESET);
>  	exynos_lpass_core_sw_reset(lpass, LPASS_MEM_SW_RESET);
> +
> +	return 0;
>  }
>  
>  static void exynos_lpass_disable(struct exynos_lpass *lpass)
> @@ -112,6 +118,7 @@ static int exynos_lpass_probe(struct platform_device *pdev)
>  	struct exynos_lpass *lpass;
>  	void __iomem *base_top;
>  	struct resource *res;
> +	int ret;
>  
>  	lpass = devm_kzalloc(dev, sizeof(*lpass), GFP_KERNEL);
>  	if (!lpass)
> @@ -136,7 +143,13 @@ static int exynos_lpass_probe(struct platform_device *pdev)
>  	platform_set_drvdata(pdev, lpass);
>  	pm_runtime_set_active(dev);
>  	pm_runtime_enable(dev);
> -	exynos_lpass_enable(lpass);
> +	ret = exynos_lpass_enable(lpass);
> +	if (ret) {
> +		pm_runtime_disable(dev);
> +		pm_runtime_set_suspended(dev);
> +		regmap_exit(lpass->top);
> +		return ret;
> +	}
>  
>  	return devm_of_platform_populate(dev);
>  }
> @@ -167,9 +180,7 @@ static int __maybe_unused exynos_lpass_resume(struct device *dev)
>  {
>  	struct exynos_lpass *lpass = dev_get_drvdata(dev);
>  
> -	exynos_lpass_enable(lpass);
> -
> -	return 0;
> +	return exynos_lpass_enable(lpass);
>  }
>  
>  static const struct dev_pm_ops lpass_pm_ops = {
> -- 
> 1.9.1
>