linux-kernel - Re: [PATCH 1/3] opp: core: add regulators enable and disable

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Message-ID: <2f02b5bb-6258-754d-d2d2-bd73e34b0dbc@partner.samsung.com>
Date:   Wed, 10 Jul 2019 12:42:26 +0200
From:   Kamil Konieczny <k.konieczny@...tner.samsung.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kukjin Kim <kgene@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Mark Rutland <mark.rutland@....com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Nishanth Menon <nm@...com>, Rob Herring <robh+dt@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Viresh Kumar <vireshk@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH 1/3] opp: core: add regulators enable and disable



On 10.07.2019 12:16, Kamil Konieczny wrote:
> 
> 
> On 09.07.2019 07:40, Viresh Kumar wrote:
>> On 08-07-19, 16:11, k.konieczny@...tner.samsung.com wrote:
>>> From: Kamil Konieczny <k.konieczny@...tner.samsung.com>
>>>
>>> Add enable regulators to dev_pm_opp_set_regulators() and disable
>>> regulators to dev_pm_opp_put_regulators(). This prepares for
>>> converting exynos-bus devfreq driver to use dev_pm_opp_set_rate().
>>>
>>> Signed-off-by: Kamil Konieczny <k.konieczny@...tner.samsung.com>
>>> ---
>>>  drivers/opp/core.c | 13 +++++++++++++
>>>  1 file changed, 13 insertions(+)
>>>
>>> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
>>> index 0e7703fe733f..947cac452854 100644
>>> --- a/drivers/opp/core.c
>>> +++ b/drivers/opp/core.c
>>> @@ -1580,8 +1580,19 @@ struct opp_table *dev_pm_opp_set_regulators(struct device *dev,
>>>  	if (ret)
>>>  		goto free_regulators;
>>>  
>>> +	for (i = 0; i < opp_table->regulator_count; i++) {
>>> +		ret = regulator_enable(opp_table->regulators[i]);
>>> +		if (ret < 0)
>>> +			goto disable;
>>> +	}
>>
>> I am wondering on why is this really required as this isn't done for
>> any other platform, probably because the regulators are enabled by
>> bootloader and are always on.
> 
> It was not enabled for historical reasons, from design point regualtors
> should be enabled before use.
 
On Exynos platform devfreq driver (exynos-bus) always enabled them,
so I wanted to preserve the current behaviour.

I've also checked the change with cpufreq-dt driver and it doesn't cause
issues.

Do you find this change acceptable?


-- 
Best regards,
Kamil Konieczny
Samsung R&D Institute Poland