Re: [PATCH] am35xx-emac: move generic EMAC init to separate file

[Ilya Yanok <yanok@emcraft.com>]

Hi Paul,

On 16.12.2011 10:13, Paul Walmsley wrote:
>> Ok, let's wait for Paul's answer and then I'll prepare a separate patch.
> 
> Unfortunately the AM3517 TRM (SPRUGR0) here doesn't really have the same 
> level of clock integration information that the WBU TRMs have, so it's 
> kind of hard to tell what's going on :-(
> 
> Looking at Figure 22-1 "EMAC and MDIO Block Diagram", it appears that what 
> we call "emac_fck" is really just an optional functional clock for the 
> MDIO PHY?

Hm. I have to admit I'm completely lost here.
CONTROL_IPSS_CLK_CTRL register has bit controlling "Func clock of
CPGMAC". But there is no mention of this clock anywhere else in the
manual. I can't find neither where it comes from nor how it's used.
According to the current sources it comes from external 50MHz RMII
clock, do you think this is correct?

EMAC section speaks something about variable frequency peripheral clock
which is used to generate MDIO bus clock signal. But I can't find any
information on that clock in the other parts of the document. It seems
to me the EMAC section was just copied from DaVinci RM without any
editing...

> And it sounds like the AM35xx clock that we call "emac_ick" is actually a 
> combined interface and functional clock for the EMAC and MDIO IP blocks?  
> I guess a combined interface/functional clock would make sense, since the 
> EMAC seems to contain a DMA controller.
>   
> Maybe Ranjith can provide some more information; he's cc'ed.
> 
> In any case, your changes sound reasonable to me, so a patch to the clock 
> file sounds good.  I'd suggest both changing the clkdev aliases and 
> renaming emac_fck - that's a confusing name and I don't think it's in the 
> TRM as such.

Actually it's called Func clock in the manual (see
CONTROL_IPSS_CLK_CTRL). Do you still think we have to rename it?

I have another concern: changing clkdev aliases make things work for me
but now I'm not sure if this change is really correct...

Regards, Ilya.