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Message-ID: <2e688177-7a69-051f-2d2c-c8067c38f3be@samsung.com>
Date:   Fri, 29 Sep 2023 14:00:54 +0200
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Subject: Re: [PATCH v2 4/7] thermal: exynos: simplify regulator
 (de)initialization
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To:     Daniel Lezcano <daniel.lezcano@linaro.org>,
        m.majewski2@samsung.com,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "linux-samsung-soc@vger.kernel.org" 
        <linux-samsung-soc@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc:     Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        ALIM AKHTAR <alim.akhtar@samsung.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
In-Reply-To: <10e6377e-ab3f-c318-9860-56ff3b8aed92@linaro.org>
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Precedence: bulk

On 29.09.2023 13:45, Daniel Lezcano wrote:
> On 29/09/2023 13:03, Marek Szyprowski wrote:
>> 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.
>
> The code before this change calls devm_regulator_get_optional() which 
> returns -ENODEV too, right ? But there is no special case for this error.
>
> So this change uses devm_regulator_get_enable_optional() and handle 
> the ENODEV as a non-error, so there is a change in the behavior.


It looks that the original code ignores any non-EPROBE_DEFER errors from 
devm_regulator_get_optional(). That's a bug, indeed.


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