linux-kernel - Re: [PATCH v2 4/7] thermal: exynos: simplify regulator (de)initialization

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Message-ID: <a6f943be-a92f-f9ec-4103-7edc70a2c9a8@samsung.com>
Date:   Fri, 29 Sep 2023 13:03:01 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        m.majewski2@...sung.com,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     Bartlomiej Zolnierkiewicz <bzolnier@...il.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        ALIM AKHTAR <alim.akhtar@...sung.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH v2 4/7] thermal: exynos: simplify regulator
 (de)initialization

On 29.09.2023 12:46, Daniel Lezcano wrote:
> On 26/09/2023 13:02, Mateusz Majewski wrote:
>> Hi,
>>
>>> This is not equivalent. If regulator is provided and enable fails, the
>>> old code is nicely returning error. Now, it will print misleading
>>> message - failed to get regulator - and continue.
>>>
>>> While this simplifies the code, it ignores important running 
>>> condition -
>>> having regulator enabled.
>>
>> Would doing this be correct?
>>
>> ret = devm_regulator_get_enable_optional(&pdev->dev, "vtmu");
>> switch (ret) {
>> case 0:
>> case -ENODEV:
>
> Not sure to understand why -NODEV is not an error


Because this what devm_regulator_get_enable_optional() returns if no 
regulator is defined. I also got confused by this a few times.


>
>>     break;
>> case -EPROBE_DEFER:
>>     return -EPROBE_DEFER;
>> default:
>>     dev_err(&pdev->dev, "Failed to get enabled regulator: %d\n",
>>         ret);
>>     return ret;
>> }
>
> ret = devm_regulator_get_enable_optional(&pdev->dev, "vtmu");
> if (ret < 0) {
>     if (ret != EPROBE_DEFER)
>         dev_err(&pdev->dev, "Failed to get enabled regulator: %d\n", 
> ret);
>     return ret;
> }
>
> ??
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland