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Subject: Re: [PATCH v2] regulator: core: Resolve supply name earlier to
 prevent double-init
From:   =?utf-8?Q?Christian_Kohlsch=C3=BCtter?= 
        <christian@kohlschutter.com>
In-Reply-To: <166083617547.142744.6260121456450934801.b4-ty@kernel.org>
Date:   Fri, 28 Oct 2022 18:59:36 +0200
Cc:     wens@kernel.org, =?utf-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Linux MMC List <linux-mmc@vger.kernel.org>,
        Markus Reichl <m.reichl@fivetechno.de>,
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References: <3B4AE882-0C28-41E3-9466-F8E301567627@kohlschutter.com>
 <YtlqPbbBceBmekcV@sirena.org.uk>
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To:     Mark Brown <broonie@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>
Precedence: bulk

> On 18. Aug 2022, at 17:22, Mark Brown <broonie@kernel.org> wrote:
>=20
> On Fri, 22 Jul 2022 19:42:27 +0200, Christian Kohlsch=C3=BCtter wrote:
>> Previously, an unresolved regulator supply reference upon calling
>> regulator_register on an always-on or boot-on regulator caused
>> set_machine_constraints to be called twice.
>>=20
>> This in turn may initialize the regulator twice, leading to voltage
>> glitches that are timing-dependent. A simple, unrelated configuration
>> change may be enough to hide this problem, only to be surfaced by
>> chance.
>>=20
>> [...]
>=20
> Applied to
>=20
> https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git =
for-next
>=20
> Thanks!
>=20
> [1/1] regulator: core: Resolve supply name earlier to prevent =
double-init
>    commit: 8a866d527ac0441c0eb14a991fa11358b476b11d
>=20
> All being well this means that it will be integrated into the =
linux-next
> tree (usually sometime in the next 24 hours) and sent to Linus during
> the next merge window (or sooner if it is a bug fix), however if
> problems are discovered then the patch may be dropped or reverted.
>=20
> You may get further e-mails resulting from automated or manual testing
> and review of the tree, please engage with people reporting problems =
and
> send followup patches addressing any issues that are reported if =
needed.
>=20
> If any updates are required or you are submitting further changes they
> should be sent as incremental updates against current git, existing
> patches will not be replaced.
>=20
> Please add any relevant lists and maintainers to the CCs when replying
> to this mail.
>=20
> Thanks,
> Mark

I've finally managed to publish a blog post about this journey into =
regulator land; I hope you find it worthwhile.
https://kohlschuetter.github.io/blog/posts/2022/10/28/linux-nanopi-r4s/

Thanks to everybody involved for getting this far!
Special thanks go to Robin Murphy for pulling out the oscillator, and =
Mark Brown for helping that these changes get into 6.1.

Best,
Christian