[PATCH V2] davinci: da850: move input frequency to board specific files

Kevin Hilman khilman at ti.com
Thu Jun 16 11:06:28 EDT 2011

"Nori, Sekhar" <nsekhar at ti.com> writes:

> On Wed, Jun 08, 2011 at 17:38:25, Nori, Sekhar wrote:
>> On Tue, Jun 07, 2011 at 21:53:59, Hilman, Kevin wrote:
>> > I don't expect this to be a big boot-time impact.
>> You are right. Using PRINTK_TIME on DM365 I saw no noticeable boot-time
>> change. When I profiled the code using do_gettimeofday(), I saw it
>> was taking ~95 usecs to complete the propagation. I was mainly worried
>> about all the recursion and reading of PLL and sysclk registers. Seems
>> its not so bad.
>> > However, some of the clock.c assumptions might need to be updated as it
>> > currently is written from the perspective that the PLL clocks are the
>> > "root" clocks.
>> Hmm, just calling clk_set_rate() on refclk propagated the rate
>> nicely across the tree. It seems DaVinci clock code is not in
>> such a bad shape :) Or did I miss the concern?
>> > Setting (and propagating) clock rates is what the clock framework is
>> > for, so adding a new interface to set a custom clock rate just doesn't
>> > seem right.  I understand that the reference oscillator might be
>> > considered a special case, but if this can be done with the clock
>> > framework, it is much preferred.
>> Okay. Will modify the DM6467/T EVM code to use this method
>> instead.
> So, here is the patch. I suspect reference clock information
> should come from devicetree data when available. I hope it is
> OK to take this approach till that time?
> Thanks,
> Sekhar
> -----8<------------
> From: Sekhar Nori <nsekhar at ti.com>
> Date: Thu, 2 Jun 2011 14:10:50 +0530
> Subject: [PATCH 1/1] davinci: dm6467/T EVM: fix setting up of reference clock rate
> The DM6467 and DM6467T EVMs use different reference clock
> frequencies. This difference is currently supported by having
> the SoC code call a public board routine which sets up the reference
> clock frequency. This does not scale as more boards are added.
> Instead, use the clk_set_rate() API to setup the reference clock
> frequency to a different value from the board file.
> Suggested-by: Kevin Hilman <khilman at ti.com>
> Signed-off-by: Sekhar Nori <nsekhar at ti.com>

Acked-by: Kevin Hilman <khilman at ti.com>

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