From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Rex-BC Chen <rex-bc.chen@mediatek.com>,
rafael@kernel.org, viresh.kumar@linaro.org, robh+dt@kernel.org,
krzk+dt@kernel.org, matthias.bgg@gmail.com
Cc: jia-wei.chang@mediatek.com, roger.lu@mediatek.com,
hsinyi@google.com, khilman@baylibre.com,
angelogioacchino.delregno@collabora.com,
linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org,
Project_Global_Chrome_Upstream_Group@mediatek.com
Subject: Re: [PATCH V4 01/14] dt-bindings: cpufreq: mediatek: Add MediaTek CCI property
Date: Mon, 25 Apr 2022 12:52:55 +0200 [thread overview]
Message-ID: <9ff80bc2-d63b-14aa-5769-20bff6e3a21e@linaro.org> (raw)
In-Reply-To: <c1b910098a0a5cbe06ec971c1bf745ac37986274.camel@mediatek.com>
On 25/04/2022 12:20, Rex-BC Chen wrote:
>> However I am not sure if you solved your problem... see below:
>>
>>> For example:
>>> mediatek cci set 1.2V originally. When cpufreq want to adjust lower
>>> frequency adn set voltage to 1.0V.
>>> The framework will remain using 1.2V to prevent crash of mediatek
>>> cci.
>>
>> No, regulator_set_voltage() for proc_reg says:
>> "NOTE: If the regulator is shared between several devices then the
>> lowest
>> request voltage that meets the system constraints will be used."
>>
>> Not the highest. So when your devfreq and cpufreq boots, calling
>> regulator_set_voltage will still cause high frequency and low
>> voltage.
>>
>
> From the driver comment, I think it still needs to match "meets the
> system constraints".
>
> From drivers, we can trace the driver and it finally to
> regulator_get_optimal_voltage().
> In [1], the framework will get max voltage while finding each device's
> voltage.
>
> [1]:
> https://elixir.bootlin.com/linux/latest/source/drivers/regulator/core.c#L3815
Right, actually in your case it's the regulator_check_consumers() above
that line, because you
I think it's quite generic problem, so would be worth solving for more
regulator consumers, but your approach is fine. At least I do not have
anything smarter, at the moment.
Best regards,
Krzysztof
next prev parent reply other threads:[~2022-04-25 10:53 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-22 7:52 [PATCH V4 00/14] cpufreq: mediatek: Cleanup and support MT8183 and MT8186 Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 01/14] dt-bindings: cpufreq: mediatek: Add MediaTek CCI property Rex-BC Chen
2022-04-22 8:21 ` AngeloGioacchino Del Regno
2022-04-22 17:26 ` Krzysztof Kozlowski
2022-04-22 17:34 ` Krzysztof Kozlowski
2022-04-25 6:19 ` Rex-BC Chen
2022-04-25 8:55 ` Krzysztof Kozlowski
2022-04-25 10:20 ` Rex-BC Chen
2022-04-25 10:52 ` Krzysztof Kozlowski [this message]
2022-04-26 8:26 ` Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 02/14] cpufreq: mediatek: Use device print to show logs Rex-BC Chen
2022-04-25 5:10 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 03/14] cpufreq: mediatek: Replace old_* with pre_* Rex-BC Chen
2022-04-25 5:11 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 04/14] cpufreq: mediatek: Record previous target vproc value Rex-BC Chen
2022-04-22 8:21 ` AngeloGioacchino Del Regno
2022-04-25 5:12 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 06/14] cpufreq: mediatek: Move voltage limits to platform data Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 07/14] cpufreq: mediatek: Add .get function Rex-BC Chen
2022-04-22 8:21 ` AngeloGioacchino Del Regno
2022-04-25 5:35 ` Viresh Kumar
2022-04-25 9:34 ` Rex-BC Chen
2022-04-25 10:00 ` Viresh Kumar
2022-04-26 11:13 ` Rex-BC Chen
2022-04-27 3:11 ` Viresh Kumar
2022-04-28 11:16 ` Rex-BC Chen
2022-04-28 11:48 ` Viresh Kumar
2022-05-03 11:33 ` Rex-BC Chen
2022-05-04 8:22 ` Viresh Kumar
2022-05-04 11:57 ` Rex-BC Chen
2022-05-04 11:58 ` Viresh Kumar
2022-05-04 12:03 ` Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 08/14] cpufreq: mediatek: Make sram regulator optional Rex-BC Chen
2022-04-25 5:36 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 09/14] cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking() Rex-BC Chen
2022-04-22 8:20 ` AngeloGioacchino Del Regno
2022-04-22 7:52 ` [PATCH V4 10/14] cpufreq: mediatek: Link CCI device to CPU Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 11/14] cpufreq: mediatek: Add support for MT8186 Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 12/14] arm64: dts: mediatek: Add opp table and clock property for MT8183 cpufreq Rex-BC Chen
2022-04-22 8:20 ` AngeloGioacchino Del Regno
2022-04-22 7:52 ` [PATCH V4 13/14] arm64: dts: mediatek: Add MediaTek CCI node for MT8183 Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 14/14] arm64: dts: mediatek: Add mediatek,cci property for MT8183 cpufreq Rex-BC Chen
2022-04-22 17:23 ` [PATCH V4 00/14] cpufreq: mediatek: Cleanup and support MT8183 and MT8186 Krzysztof Kozlowski
2022-04-25 6:20 ` Rex-BC Chen
[not found] ` <20220422075239.16437-6-rex-bc.chen@mediatek.com>
2022-04-25 5:20 ` [PATCH V4 05/14] cpufreq: mediatek: Add opp notification support Viresh Kumar
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