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From: ulf.hansson@linaro.org (Ulf Hansson)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 2/4] mmc: core: Add mmc_regulator_set_vqmmc()
Date: Fri, 20 Mar 2015 11:55:50 +0100	[thread overview]
Message-ID: <CAPDyKFroe9N3j9oMWKknH5huv7j8fkrBr5UKjjp190hkqNsNRg@mail.gmail.com> (raw)
In-Reply-To: <20150319113646.GQ2869@sirena.org.uk>

On 19 March 2015 at 12:36, Mark Brown <broonie@kernel.org> wrote:
> On Thu, Mar 19, 2015 at 12:14:11PM +0100, Ulf Hansson wrote:
>
>> Agree. Moreover we need that API to also pick the closest value to
>> target, when trying the range "target->minimum". I also believe it
>
> The implementation *should* do that anyway, it's just not trivial to
> implement in an efficient fashion with the current information we have
> from drivers.

The APIs regulator_count_voltages() and regulator_list_voltage(), are
currently used from the mmc core to find out which voltages that is
supported (with 0.1V granularity). Then that information can be used
when trying to set a new voltage.

But I guess such a wrapper API is out of the question?

Anyway, I get the feeling that we will need to do the same for this case.

>
>> would be good to allow both upper and lower limits to be zero.
>
> The lower limit can be zero already though it isn't clear to me that
> this is useful.  Setting an upper limit of zero seems nonsensical, an
> upper limit that is lower than the lower limit isn't terribly obvious
> and removing the upper limit isn't safe - it means that we'll happily
> oversupply things which is a road to physical damage.

I am not sure I follow here. In the regulator_set_voltage_tol() you
can only specifiy one limit (tolerance?). What Dough proposed was to
add a new API which can have both a low tolerance value and a high
tolerance value.

Kind regards
Uffe

  reply	other threads:[~2015-03-20 10:55 UTC|newest]

Thread overview: 23+ 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
2015-03-19  4:09         ` Doug Anderson
2015-03-19 11:14           ` Ulf Hansson
2015-03-19 11:36             ` Mark Brown
2015-03-20 10:55               ` Ulf Hansson [this message]
2015-03-20 11:28                 ` Mark Brown
2015-04-07 20:05                   ` Doug Anderson
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
2015-03-11 22:15 ` [PATCH v4 4/4] ARM: dts: Specify VMMC and VQMMC on rk3288-evb Doug Anderson
2015-03-11 23:30   ` Heiko Stuebner
2015-04-07 21:37     ` Heiko Stübner
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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