Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v2 28/48] soc/tegra: Introduce core power domain driver
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Mark Brown <broonie@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Peter Geis <pgwipeout@gmail.com>,
        Nicolas Chauvet <kwizart@gmail.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Kevin Hilman <khilman@kernel.org>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        Viresh Kumar <vireshk@kernel.org>,
        Stephen Boyd <sboyd@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-media@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-clk@vger.kernel.org
References: <20201217180638.22748-1-digetx@gmail.com>
 <20201217180638.22748-29-digetx@gmail.com>
 <20201222064029.duuzcsj53rt7xzvt@vireshk-i7>
 <c130f78d-3d97-9b26-be77-951fee0d8680@gmail.com>
 <3a5c00e5-2cdd-35ce-2714-d4ffbf9d516a@gmail.com>
 <20201223055715.2n5eba7fohrwpgr5@vireshk-i7>
 <239642ad-d7e9-364e-80d3-1da67625e247@gmail.com>
 <20201224065142.7rhfx37wgg3ejjqm@vireshk-i7>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <a1e3c706-9a8a-00b2-6ccb-08b95ee0b45b@gmail.com>
Date:   Thu, 24 Dec 2020 15:14:11 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.4.2
MIME-Version: 1.0
In-Reply-To: <20201224065142.7rhfx37wgg3ejjqm@vireshk-i7>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

24.12.2020 09:51, Viresh Kumar пишет:
> On 23-12-20, 23:37, Dmitry Osipenko wrote:
>> 23.12.2020 08:57, Viresh Kumar пишет:
>>> What's wrong with getting the regulator in the driver as well ? Apart from the
>>> OPP core ?
>>
>> The voltage syncing should be done for each consumer regulator
>> individually [1].
>>
>> Secondly, regulator core doesn't work well today if the same regulator
>> is requested more than one time for the same device.
> 
> Hmm...
> 
>>>> will return the OPP table regulator in order to allow driver to use the
>>>> regulator directly. But I'm not sure whether this is a much better
>>>> option than the opp_sync_regulators() and opp_set_voltage() APIs.
>>>
>>> set_voltage() is still fine as there is some data that the OPP core has, but
>>> sync_regulator() has nothing to do with OPP core.
>>>
>>> And this may lead to more wrapper helpers in the OPP core, which I am afraid of.
>>> And so even if it is not the best, I would like the OPP core to provide the data
>>> and not get into this. Ofcourse there is an exception to this, opp_set_rate.
>>>
>>
>> The regulator_sync_voltage() should be invoked only if voltage was
>> changed previously [1].
>>
>> The OPP core already has the info about whether voltage was changed and
>> it provides the necessary locking for both set_voltage() and
>> sync_regulator(). Perhaps I'll need to duplicate that functionality in
>> the PD driver, instead of making it all generic and re-usable by other
>> drivers.
>>
>> [1]
>> https://elixir.bootlin.com/linux/v5.10.2/source/drivers/regulator/core.c#L4107
> 
> Lets do it in the OPP core and see where we go.
> 

Alright, thank you.