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

[Chen-Yu Tsai]

Hi,

On Mon, Jan 27, 2014 at 4:43 PM, Jyri Sarha <jsarha at ti.com> wrote:
> 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.

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