lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 11 Aug 2014 14:46:54 +0200
From:	Ulf Hansson <>
To:	Linus Walleij <>,
	Heiko Stübner <>
Cc:	Mark Brown <>, Addy Ke <>,
	"" <>
Subject: Re: io-domain voltages as regulators?

On 11 August 2014 09:44, Linus Walleij <> wrote:
> On Mon, Aug 4, 2014 at 12:18 AM, Heiko Stübner <> wrote:
> [Adding Ulf Hansson to this discussion...]
>> Hi Mark, Linus,
>> I'd like to clarify what the appropriate way to handle pin output voltages is.
>> On the Rockchip SoCs the voltage for some groups of pins can be set between
>> 3.3V and 1.8V ... like the MMC/SD pins who need this to support UHS mode
>> cards.
> This is called "vqmmc" in the mmc/sd subsystem.
> grep for mmc_set_signal_voltage() in drivers/mmc/core/*
> In drivers/mmc/core/core.c, you find:
>  mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
> Which gets the regulator to set the signal voltage, if such
> a regulator is specified for the host.
> Very simple and straight-forward, and handled by the MMC core.
>> In [0] when talking about something different, Linus Walleij described a
>> similar case as
>> "I think we need to have a discussion with Mark Brown on how to
>> handle this.
>> We have previously had the case of MMC/SD level-shifters, where
>> a certain setting gives a certain level of signals out, and another setting
>> gives another level. Like two discrete levels.
>> So we modeled that as a regulator provider inside the pin control
>> driver eventually, see sh-pfc/pfc-sh73a0.c"
>> As this sound like exactly the thing I'm trying to solve, is handling this via
>> a regulator the correct general way?
> Ithinkso.

Just to confirm, I fully agree with the above said.

You may also find a good example in the mmci host driver for how to
make use of the vqmmc regulator.

Kind regards
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists