[PATCH 0/4] Migrate PXA27x platforms to clock framework

On Fri, Jul 4, 2014 at 6:14 AM, Robert Jarzmik [off-list ref] wrote:

Haojian Zhuang [off-list ref] writes:

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Haojian, are you ok with that ? And BTW, does a combined kernel for PXA
platforms even exists (mixing pxa3xx and pxa2xx for example) ?

It's acceptable to me that different silicons are queued in different stages.
I only request that it won't break the compiler building & bootup.

OK.

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But I think that the pxa clock driver may be shared among all PXA silicons
except for the clock table. What's your opinion?

I don't think so because of the core clocks.
These ones are specific to each pxa, and so their computation is :
 - pxa25x plays with CCCR and specific L, M and N2 multiplication tables
 - pxa27x plays with CCCR and specific L, M and N2 multiplication tables
 - pxa3xx plays with ASCR, MEMCLKCFG, and AC97 div

I don't see very well how a clock table could describe that. Do you have
something specific in mind ?

As I remember, those registers bits are encoded. So we can define a clock mux
that connected to those fixed clock dividers. Then the clock gate is
the child of
the clock mux.

In DTS file, peripheral device node could specify a clock rate. In
peripheral device
driver, it could also change the clock rate by clk_set_rate().

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Also (for my understanding) when you say that you plan to do
pxa25x and pxa3xx next, does that include pxa26x and pxa93x?

I don't have the Technical Reference Manuals for these ones so the answer is
no. And Google wasn't a great friend at providing them.

Converting them into new clock driver may not rely on the reference manual.

Actually I went through the code and :
 - pxa26x is only a superset of pxa25x with one more clock : pxa26x-gpio
 - pxa93x is the same clock set as pxa3xx, right ?
So if I convert pxa25x, pxa27x and pxa3xx I'll cover everything, right ?

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I assume it does as they are apparently minor revisions of the
former, but it's not completely clear from your description.

My description doesn't mention them, as I have no information about them, nor
any hardware to test on.

We can request others to help testing in the mailing list.

That's exactly what will enable pxa25x and pxa3xx. I have them converted in my
tree, but I don't want to mix these patches in as I can't test them, and testing
brings in bigger delays.

Delay shouldn't be the block issue.

Regards
Haojian