From: Tony Lindgren <tony@atomide.com>
To: Faiz Abbas <faiz_abbas@ti.com>
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-omap@vger.kernel.org, mark.rutland@arm.com,
robh+dt@kernel.org, robertcnelson@gmail.com
Subject: Re: [PATCH] ARM: dts: am57xx: Disable voltage switching for SD card
Date: Thu, 27 Jun 2019 04:39:04 -0700 [thread overview]
Message-ID: <20190627113904.GI5447@atomide.com> (raw)
In-Reply-To: <20190619102454.5097-1-faiz_abbas@ti.com>
* Faiz Abbas <faiz_abbas@ti.com> [190619 03:25]:
> If UHS speed modes are enabled, a compatible SD card switches down to
> 1.8V during enumeration. If after this a software reboot/crash takes
> place and on-chip ROM tries to enumerate the SD card, the difference in
> IO voltages (host @ 3.3V and card @ 1.8V) may end up damaging the card.
>
> The fix for this is to have support for power cycling the card in
> hardware (with a PORz/soft-reset line causing a power cycle of the
> card). Because the beaglebone X15 (rev A,B and C), am57xx-idks and
> am57xx-evms don't have this capability, disable voltage switching for
> these boards.
>
> The major effect of this is that the maximum supported speed
> mode is now high speed(50 MHz) down from SDR104(200 MHz).
>
> commit 88a748419b84 ("ARM: dts: am57xx-idk: Remove support for voltage
> switching for SD card") did this only for idk boards. Do it for all
> affected boards.
Thanks applying into fixes.
Regards,
Tony
prev parent reply other threads:[~2019-06-27 11:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 10:24 [PATCH] ARM: dts: am57xx: Disable voltage switching for SD card Faiz Abbas
2019-06-27 11:39 ` Tony Lindgren [this message]
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