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From: Ulf Hansson <ulf.hansson@linaro.org>
To: Mark Brown <broonie@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>,
	Heiko Stuebner <heiko@sntech.de>,
	Jaehoon Chung <jh80.chung@samsung.com>,
	Seungwon Jeon <tgih.jun@samsung.com>,
	Alexandru Stan <amstan@chromium.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Sonny Rao <sonnyrao@chromium.org>,
	Andrew Bresticker <abrestic@chromium.org>,
	Addy Ke <addy.ke@rock-chips.com>,
	Javier Martinez Canillas <javier.martinez@collabora.co.uk>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Chris Ball <chris@printf.net>,
	Johan Rudholm <johan.rudholm@axis.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Tim Kryger <tim.kryger@gmail.com>,
	Andrew Gabbasov <andrew_gabbasov@mentor.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kerne>
Subject: Re: [PATCH v4 2/4] mmc: core: Add mmc_regulator_set_vqmmc()
Date: Tue, 17 Mar 2015 12:28:34 +0100	[thread overview]
Message-ID: <CAPDyKFqGYqNCbGGzw7orXLT+pkxK5LMUDTYWju405tqynPMyCQ@mail.gmail.com> (raw)
In-Reply-To: <20150317103829.GA28806@sirena.org.uk>

On 17 March 2015 at 11:38, Mark Brown <broonie@kernel.org> wrote:
> On Tue, Mar 17, 2015 at 11:23:33AM +0100, Ulf Hansson wrote:
>> On 16 March 2015 at 16:12, Doug Anderson <dianders@chromium.org> wrote:
>
>> > * Try to set the voltage to exactly 1,200,000 uV (1.2V).
>> > * If you can't get 1.2V exactly, a tolerance ("tol") of 100,000 uV
>> > (.1V) is OK.
>> > * In other words, 1.1V - 1.3V are OK, but aim for 1.2V
>
>> So what happens in the case when 1.3V and 1.1V, but not 1.2V. Which
>> value will be used? Is that algorithm defined by the regulator core or
>> does it depend per regulator implementation?
>
> It's done in the core.  It first tries to hit the target voltage to the
> maximum (picking the lowest voltage in that range) then tries to pick
> the lowest voltage to the target, though that's an implementation detail
> and we really should be trying to get as close as possible to the
> target.  We don't do that yet because it can be expensive to work out so
> we do the current thing which is cheap and mostly good enough.

Okay, so that seems to work well for our 1.1V->1.3V case.

Thanks!

Kind regards
Uffe

  reply	other threads:[~2015-03-17 11:28 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-11 22:15 [PATCH v4 1/4] mmc: dw_mmc: Don't try to enable the CD until we're sure we're not deferring Doug Anderson
2015-03-11 22:15 ` [PATCH v4 2/4] mmc: core: Add mmc_regulator_set_vqmmc() Doug Anderson
2015-03-16 14:05   ` Ulf Hansson
2015-03-16 15:12     ` Doug Anderson
2015-03-17 10:23       ` Ulf Hansson
2015-03-17 10:38         ` Mark Brown
2015-03-17 11:28           ` Ulf Hansson [this message]
2015-03-19  4:09         ` Doug Anderson
2015-03-19 11:14           ` Ulf Hansson
     [not found]             ` <CAPDyKFrkznbW7k_=BDo99jJhWzDbUgbeU+MXWB_E_UWXh=56Eg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-03-19 11:36               ` Mark Brown
2015-03-20 10:55                 ` Ulf Hansson
     [not found]                   ` <CAPDyKFroe9N3j9oMWKknH5huv7j8fkrBr5UKjjp190hkqNsNRg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-03-20 11:28                     ` Mark Brown
2015-04-07 20:05                       ` Doug Anderson
     [not found]                         ` <CAD=FV=WpDE_iEFWFw094WBfBH2TgRi+1OGk3E3qQ3t1EfyrnJA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-04-08 11:28                           ` Mark Brown
2015-03-11 22:15 ` [PATCH v4 3/4] mmc: dw_mmc: Use mmc_regulator_set_vqmmc in start_signal_voltage_switch Doug Anderson
2015-03-13 11:32 ` [PATCH v4 1/4] mmc: dw_mmc: Don't try to enable the CD until we're sure we're not deferring Jaehoon Chung
2015-03-13 12:10   ` Heiko Stuebner
2015-03-16  2:09     ` Jaehoon Chung
2015-03-27  5:55 ` Jaehoon Chung
2015-03-27 15:46   ` Doug Anderson

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