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

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Message-id: <8365fa18-78c5-5fdf-f6d6-6c0491ce262f@samsung.com>
Date:   Thu, 10 Aug 2017 08:24:33 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>,
        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>,
        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

Hi All,

On 2017-08-10 08:01, Krzysztof Kozlowski wrote:
> 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).

Works fine on Exynos5433 based TM2e.

Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

>
> 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

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland