[PATCH 1/3] mmc: add support for power-on sequencing through DT

[Fabio Estevam]

On Mon, Jan 20, 2014 at 2:48 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:

> So far so good.  Now, what about this external oscillator which has its
> own separate power control.  My immediate thought is that this can be
> specified via card_ext_clock - I would simply need to declare a fixed-rate
> clock with either a regulator (power switch) controlled via a gpio (which
> would probably be closer to the hardware) or a gpio as an enable... ah,
> that requires me to write a common clock driver for that bit since this
> is currently not modelled by CCF...

Jiry Sarha posted a gpio controlled clock proposal:
http://www.spinics.net/lists/devicetree/msg16651.html

Regards,

Fabio Estevam