Limit mmc0 and mmc1 clock frequency

[Sergey Manucharian]

I'm trying to limit mmc clock frequency by adding the line to a .dts (kernel 4.4.16-ti-rt):

max-frequency = <25000000>;

It works only for mmc2, but not for mmc0 and mmc1.
It remains 50Mhz for mmc0 and 52Mhz for mmc1.

Thanks for ideas!

[Robert Nelson]

pretty sure that get's overriden when the mmc core probes the
eMMC/microSD.. So if you really want to disable 50/52Mhz you'll have
to disable the actual sd transfer modes..

see for example on the x15, since we don't have a dual voltage
regulator, these modes must be removed:

https://github.com/RobertCNelson/dtb-rebuilder/blob/4.4-ti/src/arm/am57xx-beagle-x15.dts#L109-L113

Regards,

--
Robert Nelson
https://rcn-ee.com/

[lorriane...@yahoo.com]

--------------------------------------------
On Wed, 12/21/16, Robert Nelson <robert...@gmail.com> wrote:

Subject: Re: [beagleboard] Limit mmc0 and mmc1 clock frequency
To: "Beagle Board" <beagl...@googlegroups.com>
Cc: s...@ara-ler.com
Date: Wednesday, December 21, 2016, 6:18 PM

--
For more options, visit http://beagleboard.org/discuss
---
You received this message
because you are subscribed to the Google Groups
"BeagleBoard" group.
To
unsubscribe from this group and stop receiving emails from
it, send an email to beagleboard...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/CAOCHtYiQN7mk6uMETWixs4W0O0_a0zArh6vtt-3FZC1QcvSn8g%40mail.gmail.com.
For
more options, visit https://groups.google.com/d/optout.
venimentele din Romania au fost dezbatute si la reuniunile ministrilor de externe ai S.U.A. U.R.S.S. Mani Britanii din 11 septembrie - 2 octombrie 1945 si respectiv 16-26 decembrie 1945. S-a decis sa se ceara Bucurestiului reorganizarea guvernului prin includerea unor reprezentanti ai P.N.L. si P.N.t. si organizarea de alegeri libere. in ultimul ceas politicienii britanici si americani schitau unele gesturi de protest fata de excesele comuniste din pacate doar simbolice caci Romania cazuse iremediabil sub dominatia sovietica. La 31 decembrie 1945 - 1 ianuarie 1946 a avut loc vizita la Bucuresti a unei delegatii mixte - Al. Vasinski U.R.S.S. Avere Harimann S.U.A. si Archibald Clark-Kerr Marea Britanie ce a comunicat factorilor romani deciziile reuniunilor ministrilor de externe ai Marilor Puteri. La 6 ianuarie 1946 prin decret regal au fost numiti in guvernul Groza Mihail Romniceanu din partea P.N.L si Emil Hatieganu din partea P.N.t. Greva regala a incetat. Peste o luna guvernul roman a fost recunoscut de guvernele occidentale.

[Sergey Manucharian]

Thanks, Robert!

However, just adding that block of "delete-property"-s from the example you pointed to didn't help.

By the way, where are those modes defined?

sd-uhs-sdr104
sd-uhs-sdr50
sd-uhs-ddr50
sd-uhs-sdr25
sd-uhs-sdr12

[Robert Nelson]

On Wed, Dec 21, 2016 at 2:19 PM, Sergey Manucharian <s...@ara-ler.com> wrote:
> Thanks, Robert!
>
> However, just adding that block of "delete-property"-s from the example you
> pointed to didn't help.

Correct it was an "example" of how to disable modes, as the ip on the
am335x doesn't even support those... ;)

> By the way, where are those modes defined?
>
> sd-uhs-sdr104
> sd-uhs-sdr50
> sd-uhs-ddr50
> sd-uhs-sdr25
> sd-uhs-sdr12

Here's the full list:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/mmc/mmc.txt

[Sergey Manucharian]

Thanks, Robert!

It works. Of course, it didn't, when trying for first time I "deleted" all  those modes.
The following lines successfully set MMC clock to 25MHz:

    max-frequency = <25000000>;
    /delete-property/ sd-uhs-sdr104;
    /delete-property/ sd-uhs-sdr50;
    /delete-property/ sd-uhs-ddr50;Sergey

On Wednesday, December 21, 2016 at 1:24:10 PM UTC-7, RobertCNelson wrote:

Correct it was an "example" of how to disable modes, as the ip on the
am335x doesn't even support those... ;)