linux-kernel - Re: FW: [PATCH v2] mmc: sdhci: apply voltage range check only for non-fixed regulators

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Date:	Tue, 20 Nov 2012 08:27:05 -0500
From:	Chris Ball <cjb@...top.org>
To:	Marek Szyprowski <m.szyprowski@...sung.com>
Cc:	Kevin Liu <keyuan.liu@...il.com>, linux-mmc@...r.kernel.org,
	linux-kernel@...r.kernel.org, kyungmin.park@...sung.com,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>, lrg@...com,
	Philip Rakity <prakity@...dia.com>
Subject: Re: FW: [PATCH v2] mmc: sdhci: apply voltage range check only for non-fixed regulators

Hi,

On Tue, Nov 20 2012, Marek Szyprowski wrote:
>> >> >> Subject: [PATCH v5 03/13] mmc: sdhci: use regulator min/max voltage
>> >> >> range according to spec
>> >> >>
>> >> >> From: Kevin Liu <kliu5@...vell.com>
>> >> >>
>> >> >> For regulator vmmc/vmmcq, use voltage range as below
>> >> >> 3.3v/3.0v: (2.7v, 3.6v)
>> >> >> 1.8v: (1.7v, 1.95v)
>> >> >> Original code use the specific value which may fail in regulator
>> >> >> driver if it does NOT support the specific voltage.
>> >> >>
>> >> >> Signed-off-by: Jialing Fu <jlfu@...vell.com>
>> >> >> Signed-off-by: Kevin Liu <kliu5@...vell.com>
>> >> >
>> >> >
>> >> > Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
>> >> >
>> >> > This patch restores sdhci devices to working state on Samsung boards
>> >> > (tested on GONI and UniversalC210) after merging "regulator: fix voltage
>> >> > check in regulator_is_supported_voltage()" patch to v3.7-rc6 (commit
>> >> > f0f98b19e23d4426ca185e3d4ca80e6aff5ef51b). Would be great to have it
>> >> > merged before the final v3.7 is out.
>> >> >
>> >> Marek,
>> >>
>> >> thanks a lot for the verification!
>> >> And your patch "mmc: sdhci: apply voltage range check only for
>> >> non-fixed regulators" (commit
>> >> d5b5205f2d480a47863dda0772d2d9dc47c2b51b, which has been merged in
>> >> mmc-next) can be reverted if this patch merged?
>> >
>> >
>> > Yes, it can be replaced with it, although there is still an issue that need
>> > to be resolved somehow. Right now SDHCI driver fails to initialize if
>> > support
>> > for dummy regulator is enabled.
>> >
>> Then I think the dummy issue can be resolved with your patch merged
>> and if you can just update your patch from
>>       "regulator_count_voltages(host->vmmc) > 1"
>> to
>>       "regulator_count_voltages(host->vmmc) > 0"
>> to let fix regulator work.
>
> regulator_count_voltages() returns 1 for both fixed regulators and for
> virtual dummy regulator, so the above change makes no sense.
>
> However I was so focused on fixing the 2.8V supply case that I missed the
> fact that my "mmc: sdhci: apply voltage range check only for non-fixed
> regulators" patch also fixed the dummy regulator case.
>
> The conclusion is that applying both patches should finally fix the
> regulator issues with for the Samsung boards (2.8V supply for eMMC) and
> 'dummy-regulators' cases.

Thanks, I've pushed v5 of "mmc: sdhci: use regulator min/max voltage
range according to spec" to mmc-next for 3.7 with Marek's Tested-by now.

- Chris.
-- 
Chris Ball   <cjb@...top.org>   <http://printf.net/>
One Laptop Per Child
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