The Problem:

On ASUS Tinker Board S, when booting from the eMMC, and there is card
in the sd slot, there are constant errors.

Also when warm reboot, uboot can not access the sd slot

Cause:

Identified by Robin Murphy @ ARM. The Card Detect on rk3288
devices is pulled up by vccio-sd; so when the regulator powers this
off, card detect gives spurious errors. A second problem, is during
power down, vccio-sd apprears to be powered down. This causes a
problem when warm rebooting from the sd card. This was identified by
Jonas Karlman.

History:

A common fault on these rk3288 board, which impliment the reference
design.

When this arose before:

http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/281153.html

And Ulf and Jaehoon clearly said this was a broken card detect design,
which should be solved via polling

Solution:

Hence broken-cd is set as a property. This cures the errors. The
powering down of vccio-sd during reboot is cured by adding
regulator-boot-on.

This solutions has been fairly widely reviewed and tested.

Fixes: e58c5e73 ("ARM: dts: rockchip: move shared tinker-board nodes to a common dtsi")
Cc: stable@vger.kernel.org
[Heiko: slightly inaccurate fixes but tinker is a sbc (aka like a Pi) where
 we can hopefully expect people not to rely on overly old stable kernels]
Signed-off-by: David Summers <beagleboard@davidjohnsummers.uk>
Reviewed-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>