From: Arnd Bergmann <arnd@arndb.de>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Mark Rutland <mark.rutland@arm.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"devicetree-discuss@lists.ozlabs.org"
<devicetree-discuss@lists.ozlabs.org>,
Chris Ball <cjb@laptop.org>, Magnus Damm <magnus.damm@gmail.com>
Subject: Re: [PATCH/RFC] mmc: add DT bindings for more MMC capability flags
Date: Thu, 07 Feb 2013 01:44:22 +0100 [thread overview]
Message-ID: <1923973.xHEn0Jh3IU@wuerfel> (raw)
In-Reply-To: <Pine.LNX.4.64.1302061720390.13474@axis700.grange>
On Wednesday 06 February 2013 17:25:42 Guennadi Liakhovetski wrote:
>
> Thank for pointing me out at that thread. However, I don't think
> MMC_CAP_POWER_OFF_CARD has anything to do with compatibility or hardware
> revisions. At least I haven't yet come across any sd/mmc hosts, that also
> supply card power. You could "derive" this flag from the presence of a
> regulator, capable of changing its status (switching on / off), but even
> then you're not guaranteed, that you actually can (and want to) power the
> card off at run-time - the regulator can be shared etc. So, an explicit
> flag is needed.
It sounds like something that should be handled in a controller specific
way I think. E.g. on SDHCI, there seems to always be a method to power
down the card using the SDHCI_POWER_CONTROL register, even without
any external regulators.
Arnd
next prev parent reply other threads:[~2013-02-06 16:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-23 16:45 [PATCH/RFC] mmc: add DT bindings for more MMC capability flags Guennadi Liakhovetski
2013-02-06 15:15 ` Mark Rutland
2013-02-06 16:25 ` Guennadi Liakhovetski
2013-02-07 0:44 ` Arnd Bergmann [this message]
2013-02-06 17:32 ` Guennadi Liakhovetski
2013-02-06 22:00 ` Arnd Bergmann
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