From: khilman@ti.com (Kevin Hilman)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V2] davinci: da850: move input frequency to board specific files
Date: Thu, 16 Jun 2011 08:06:28 -0700 [thread overview]
Message-ID: <87oc1xstmz.fsf@ti.com> (raw)
In-Reply-To: <B85A65D85D7EB246BE421B3FB0FBB593024D4CF84E@dbde02.ent.ti.com> (Sekhar Nori's message of "Tue, 14 Jun 2011 21:03:20 +0530")
"Nori, Sekhar" <nsekhar@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@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@ti.com>
> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
next prev parent reply other threads:[~2011-06-16 15:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-25 8:37 [PATCH] davinci: da850: move input frequency to board specific files Christian Riesch
2011-05-27 9:20 ` [PATCH V2] " Christian Riesch
2011-05-28 9:55 ` Menon, Nishanth
2011-05-30 8:23 ` Christian Riesch
2011-06-01 17:15 ` Nori, Sekhar
2011-06-06 22:44 ` Kevin Hilman
2011-06-07 10:39 ` Nori, Sekhar
2011-06-07 16:23 ` Kevin Hilman
2011-06-08 12:08 ` Nori, Sekhar
2011-06-14 15:33 ` Nori, Sekhar
2011-06-14 17:39 ` [PATCH] davinci: da850: add a .set_rate method to ref_clk Christian Riesch
2011-06-28 11:23 ` Nori, Sekhar
2011-06-28 15:10 ` [PATCH v2] " Christian Riesch
2011-07-06 16:36 ` Nori, Sekhar
2011-06-16 15:06 ` Kevin Hilman [this message]
2011-06-09 10:05 ` [PATCH V2] davinci: da850: move input frequency to board specific files Christian Riesch
2011-06-09 16:48 ` Nori, Sekhar
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