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SubjectRe: OMAP: clock DT conversion issues with omap36xx
On 01/29/2014 05:21 AM, Christoph Fritz wrote:
> On Tue, 2014-01-28 at 18:02 +0100, Christoph Fritz wrote:
>> On Tue, 2014-01-28 at 15:40 +0200, Tero Kristo wrote:
>>>
>>>>> Due to a regression since next-20140122 the following errors are present:
>>>>>
>>>>> - pin sys_clkout2, which gets configured to 24 Mhz by the fourth patch
>>>>> in this set, erroneously outputs only 12 Mhz.
>>>>> Just out of curiosity, configuring it to 48 Mhz puts out desired 24 Mhz.
>>>>>
>>>>> - omap_dss, which gets configured by the third patch in this set, fails
>>>>> to do 'dss_set_fck_rate(fck);' in
>>>>> drivers/video/omap2/dss/dss.c:dss_setup_default_clock() which leads to:
>>>>>
>>>>> | omapdss_dss: probe of omapdss_dss failed with error -22
>>>>> | omapdss CORE error: Failed to initialize DSS platform driver
>>>>> | panel-dpi panel-dpi.0: failed to find video source 'dpi.0
>>>>>
>>>>> Both regressions seem to have something to do with the clock framework.
>>>>> Could this be related to the DT clock conversion patches?
>>>>
>>>
>>> Yea its definitely possible, as the clock DT conversion touches pretty
>>> much everything. Have you tried whether this works properly with legacy
>>> boot? Personally I don't have access to any omap3 devices that would
>>> have display and have no possibility to check this out myself. Anyway,
>>> my initial guess is that some clock divider setup might be wrong with
>>> omap3, or we are missing some ti,set-rate-parent flag for some clock
>>> node which prevents escalating clk_set_rate properly. However, it should
>>> be easy to debug this by looking at the clock node in question, and its
>>> parent nodes to see if there are any problems.
>>
>> Currently I only analyzed sys_clkout2 (see attachments for full
>> clk_summary files):

To help us debug similar problems, I wrote a tool today:
https://github.com/nmenon/ctt-dump - it is a simple memory read utility,

Input file is CTT dump-out
For example: 3630 CTT is here:
http://www.ti.com/pdfs/wtbu/CTT-OMAP3630ES1.x-v1.6.0.4.zip

to give an idea - i posted a screen shot here:
https://plus.google.com/112464029509057661457/posts/hNdee4gNfob

After generating the the rd1 file from CTT,
we pick up the registers using ctt-dump -> any tool which can do
register reads could do, but it might be handy having this.
Example output on beagle-xm: http://slexy.org/view/s2YWmM1ium
importing it back into CTT and after setting up the correct sysclk, we
can compare clock frequencies Vs debugfs output - example:
http://slexy.org/view/s21iQyDTct


I mean, it is awesome having to debugfs data, but with nascent
systems, it is always good to compare to what the hardware is really
configured to - and CTT is the easy way to deal with it.

--
Regards,
Nishanth Menon


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