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

Hi,

On Mon, Jan 27, 2014 at 4:43 PM, Jyri Sarha [off-list ref] wrote:

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

quoted

On Mon, Jan 20, 2014 at 2:48 PM, Russell King - ARM Linux
[off-list ref] wrote:

quoted

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.

Not sure where stacking external clocks would be used, but sounds like a
fixed factor clock? Maybe you should add DT support to that if that's what
you need or have.

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

Cheers,
ChenYu