From: Sylwester Nawrocki <s.nawrocki@samsung.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: devicetree@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
linux-pm@vger.kernel.org, vireshk@kernel.org,
b.zolnierkie@samsung.com, linux-kernel@vger.kernel.org,
krzk@kernel.org, robh+dt@kernel.org, kgene@kernel.org,
pankaj.dubey@samsung.com, linux-arm-kernel@lists.infradead.org,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH v2 0/9] Exynos Adaptive Supply Voltage support
Date: Tue, 20 Aug 2019 11:03:09 +0200 [thread overview]
Message-ID: <06ccff05-2152-4bcc-7537-8f24da75f163@samsung.com> (raw)
In-Reply-To: <20190820030114.6flnn2omeys3lih3@vireshk-i7>
On 8/20/19 05:01, Viresh Kumar wrote:
> On 19-08-19, 15:39, Sylwester Nawrocki wrote:
>> Unfortunately not, the patch set as I see it is another way of updating
>> an OPP after it was parsed from DT. OPP remove/add could work equally
>> well in our use case.
>
> Adding OPPs dynamically has limitations, you can't set many values which are
> otherwise possible with DT. And removing/adding is not the right thing to do
> technically.
Thanks for explanation, I was not aware of that.
>> The problem is that we have the information on how to translate the
>> common OPP voltage to a voltage specific to given silicon encoded jointly
>> in the ASV tables and the CHIPID registers (efuse/OTP memory).
>> Additionally, algorithm of selecting ASV data (OPP voltage) based on
>> the "key" data from registers is not generic, it is usually different
>> per each SoC type.
>>
>> I tried to identify some patterns in those tables in order to simplify
>> possible DT binding, but that was not really successful. I ended up just
>> keeping whole tables.
>
> Sorry but I am unable to understand the difficulty you are facing now. So what I
> suggest is something like this.
The difficulty was about representing data from tables asv_{arm,kfc}_table[][]
added in patch 3/9 of the series in devicetree. If you have no objections
about keeping those tables in the driver then I can't see any difficulties.
> - Use DT to get a frequency and voltage for each frequency.
Yes, this is what happens now, we have common OPPs in DT that work for each SoC
revision.
> - At runtime, based on SoC, registers, efuses, etc, update the voltage of the
> OPPs.
> - This algo can be different for each SoC, no one is stopping you from doing
> that.
>
> Am I missing something ?
Not really, this is basically what happens in the $subject patch series.
Then IIUC what I would need to change is to modify exynos_asv_update_cpu_opps()
function in patch 3/9 to use dev_pm_opp_adjust_voltage() rather than
dev_pm_opp_remove(), dev_pm_opp_add().
--
Thanks,
Sylwester
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next prev parent reply other threads:[~2019-08-20 9:03 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190718143117eucas1p1e534b9075d10fbbbe427c66192205eb1@eucas1p1.samsung.com>
2019-07-18 14:30 ` [PATCH v2 0/9] Exynos Adaptive Supply Voltage support Sylwester Nawrocki
[not found] ` <CGME20190718143127eucas1p13b1e2c98d270140a87f09562ef46c9a3@eucas1p1.samsung.com>
2019-07-18 14:30 ` [PATCH v2 1/9] soc: samsung: Add exynos chipid driver support Sylwester Nawrocki
2019-07-23 12:57 ` Krzysztof Kozlowski
2019-07-23 14:10 ` Bartlomiej Zolnierkiewicz
2019-07-24 10:47 ` Krzysztof Kozlowski
2019-08-08 12:07 ` Sylwester Nawrocki
[not found] ` <CGME20190718143128eucas1p2677ae16d229dddcd9a0db8084f0da5cf@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 2/9] soc: samsung: Convert exynos-chipid driver to use the regmap API Sylwester Nawrocki
2019-07-23 13:01 ` Krzysztof Kozlowski
2019-08-08 12:07 ` Sylwester Nawrocki
[not found] ` <CGME20190718143130eucas1p26f2058f47eb2f4020e1ddbf1619d1ac8@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 3/9] soc: samsung: Add Exynos Adaptive Supply Voltage driver Sylwester Nawrocki
2019-07-23 13:38 ` Krzysztof Kozlowski
2019-08-08 12:07 ` Sylwester Nawrocki
2019-08-08 12:31 ` Krzysztof Kozlowski
2019-08-08 12:48 ` Robin Murphy
2019-08-08 13:14 ` Krzysztof Kozlowski
[not found] ` <CGME20190718143131eucas1p2e1afc9fe816fff52ee4d12e0979eeb4c@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 4/9] ARM: EXYNOS: enable exynos_chipid for ARCH_EXYNOS Sylwester Nawrocki
[not found] ` <CGME20190718143132eucas1p2afecae86f2ef17aa8a4a99df8ffa47d9@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 5/9] ARM64: " Sylwester Nawrocki
[not found] ` <CGME20190718143134eucas1p2aed09e2171d0d2d6b916dddac3637017@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 6/9] ARM: EXYNOS: Enable exynos-asv driver " Sylwester Nawrocki
[not found] ` <CGME20190718143135eucas1p2da5b7842b35327c60667064184619a9f@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 7/9] soc: samsung: Update the CHIP ID DT binding documentation Sylwester Nawrocki
[not found] ` <CGME20190718143136eucas1p2cedfe5ed5e8e6316e82b30a565dc4855@eucas1p2.samsung.com>
2019-07-18 14:30 ` [PATCH v2 8/9] ARM: dts: Add "syscon" compatible string to chipid node Sylwester Nawrocki
[not found] ` <CGME20190718143138eucas1p127542c4cb8416cee9af6a95f4bc98366@eucas1p1.samsung.com>
2019-07-18 14:30 ` [PATCH v2 9/9] ARM: dts: Add samsung,asv-bin property for odroidxu3-lite Sylwester Nawrocki
2019-07-23 2:04 ` [PATCH v2 0/9] Exynos Adaptive Supply Voltage support Viresh Kumar
2019-07-24 13:10 ` Marek Szyprowski
2019-07-25 2:23 ` Viresh Kumar
2019-08-09 15:58 ` Sylwester Nawrocki
2019-08-19 9:09 ` Viresh Kumar
2019-08-19 10:06 ` Viresh Kumar
2019-08-19 11:16 ` Sylwester Nawrocki
2019-08-19 11:25 ` Viresh Kumar
2019-08-19 13:39 ` Sylwester Nawrocki
2019-08-20 3:01 ` Viresh Kumar
2019-08-20 9:03 ` Sylwester Nawrocki [this message]
2019-08-20 9:21 ` Viresh Kumar
2019-09-04 12:37 ` Sylwester Nawrocki
2019-09-05 5:01 ` Viresh Kumar
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