SD-Card driver modification for Zynq questions

[Lee D]

On Wed, Sep 28, 2016 at 10:16 AM, Thomas Skibo <thomasskibo at yahoo.com>
 wrote:

>
> Why not just set max-frequency to 200Mhz in the DTS file entry?
>
> ——
> Thomas Skibo
> thomasskibo at yahoo.com
>
>
I hadn't thought of that.  I think you are suggesting that I tell the
driver that the clock speed is higher than it is so all of the clock
divisors are set higher, which would result in a lower data rate.

That's a clever idea,  but I think I would actually have to set the
max-frequency to 500MHz, since some cards are capable of operating up to
100MHz and my SD-Card slot can only run (safely) at 20MHz.   That means at
that all normal 25MHz cards would run dramatically slower than they need
to.

In the event that I can't figure out how to make a new DTS file parameter
for max data rate, do you think that my modification is a decent way to
accomplish my goal?

Thanks,

Lee