[U-Boot] [PATCH v2 1/2] mmc: sunxi: Support new mode

[Maxime Ripard]

Hi Jaehoon,

On Wed, Aug 23, 2017 at 08:14:53PM +0900, Jaehoon Chung wrote:
> Hi,
> 
> On 08/23/2017 07:03 PM, Maxime Ripard wrote:
> > Almost all of the newer Allwinner SoCs have a new operating mode for the
> > eMMC clocks that needs to be enabled in both the clock and the MMC
> > controller.
> > 
> > Details about that mode are sparse, and the name itself (new mode vs old
> > mode) doesn't give much details, but it seems that the it changes the
> > sampling of the MMC clock. One side effect is also that it divides the
> > parent clock rate by 2.
> > 
> > Add support for it through a Kconfig option.
> 
> Well, i don't know exactly what mode likes your mention..
> I think it can be got from dt if it's provided from controller IP or SoC.
> how about?

That's how we do it in Linux, and obviously is our long term goal in
U-Boot as well. However, the current driver in U-Boot doesn't use the
device model (and the DT), so we cannot use that for now.

Once the switch is over, we'll of course switch to something like you
suggested.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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