[PATCH 1/3] mmc: add support for power-on sequencing through DT
From: Chen-Yu Tsai <hidden>
Date: 2014-01-27 08:54:30
Also in:
linux-devicetree, linux-mmc
From: Chen-Yu Tsai <hidden>
Date: 2014-01-27 08:54:30
Also in:
linux-devicetree, linux-mmc
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.htmlI 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