From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Ulf Hansson <ulf.hansson@stericsson.com>
Cc: linux-mmc@vger.kernel.org, Chris Ball <cjb@laptop.org>,
Per Forlin <per.forlin@stericsson.com>,
Johan Rudholm <johan.rudholm@stericsson.com>,
Lee Jones <lee.jones@linaro.org>,
Jasi Brar <jassisinghbrar@gmail.com>,
Ulf Hansson <ulf.hansson@linaro.org>
Subject: Re: [PATCH] mmc: core: Prevent eMMC VCC supply to be cut from late init
Date: Wed, 9 May 2012 16:56:23 +0100 [thread overview]
Message-ID: <20120509155622.GE3955@opensource.wolfsonmicro.com> (raw)
In-Reply-To: <1336572926-21013-1-git-send-email-ulf.hansson@stericsson.com>
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On Wed, May 09, 2012 at 04:15:26PM +0200, Ulf Hansson wrote:
> From: Ulf Hansson <ulf.hansson@linaro.org>
>
> For eMMC cards that has been initialized from a bootloader,
> the VCC voltage supply must not be cut in an uncontrolled
> manner, without first sending SLEEP or POWEROFF_NOTIFY.
>
> The regulator_init_complete late initcall, may cut the VCC
> regulator if it's reference counter is zero. To be able to
> prevent the regulator from being cut, mmc_start_host, which
> should execute at device init and thus before late init,
> calls mmc_power_up. Then the host driver is able to increase
> the reference to the regulator.
This looks like a good, simple solution - working out how we avoid extra
power ups will probably be more invasive and might not be worth the
effort for something that's boot time only.
Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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next prev parent reply other threads:[~2012-05-09 15:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-09 14:15 [PATCH] mmc: core: Prevent eMMC VCC supply to be cut from late init Ulf Hansson
2012-05-09 15:56 ` Mark Brown [this message]
2012-05-09 16:56 ` Chris Ball
2012-07-10 15:19 ` Girish K S
2012-07-10 17:32 ` Chris Ball
2012-07-11 12:40 ` Girish K S
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