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

[Jyri Sarha]

On 01/24/2014 07:35 PM, Fabio Estevam wrote:
> 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
>

I have not received too much feedback to my patch yet. CCF is a bit new 
territory to me, but I think having a separate stackable clk-gpio would 
be more flexible than having the gpio property implemented in 
clk-fixed-rate.

Anyway, I am happy do it either way as long as I can get a gpio 
-controlled clock implementation into the main line.

Cheers,
Jyri