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

From: Marek Szyprowski <m.szyprowski@samsung.com>
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>
Subject: Re: [PATCH v2 4/7] thermal: exynos: simplify regulator (de)initialization
Date: Fri, 29 Sep 2023 13:03:01 +0200	[thread overview]
Message-ID: <a6f943be-a92f-f9ec-4103-7edc70a2c9a8@samsung.com> (raw)
In-Reply-To: <67a7d507-7025-ee3e-f388-0a96e11eae41@linaro.org>

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