Messages in this thread | | | Date | Thu, 16 Apr 2015 22:37:19 +0200 | From | Sebastian Hesselbarth <> | Subject | Re: AM335x OMAP2 common clock external fixed-clock registration |
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On 16.04.2015 18:17, Michael Welling wrote: > On Thu, Apr 16, 2015 at 07:32:32AM +0300, Tero Kristo wrote: >> On 04/15/2015 11:51 PM, Michael Welling wrote: >>> On Wed, Apr 15, 2015 at 01:45:53PM -0700, Mike Turquette wrote: >>>> On Wed, Apr 15, 2015 at 12:47 PM, Michael Welling <mwelling@ieee.org> wrote: [...] >>>>> There is still an issue with the si5351. >>>>> >>>>> I had to comment out the clk_put here for the frequency to show up: >>>>> http://lxr.free-electrons.com/source/drivers/clk/clk-si5351.c#L1133 >>>>> >>>>> Ideas? >>>> >>>> What is the most recent upstream commit that you are based on? >>> >>> I am working from 4.0.0-rc7. >>> >>> 7b43b47373d40d557cd7e1a84a0bd8ebc4d745ab >> >> Hmm, I wonder why si5351 calls clk_put immediately after of_clk_get >> in the first place, as far as I understand this destroys the clock >> handle, which is still being used later in the code. > > Not sure how this ever worked. This has been in the code since the > initial commit.
The reason it worked before may be related with recent rework of clk_put() itself and clk cookies instead of pointers. I lost track on the recent clk subsystem changes here, sorry.
However, droping the clk immediately surely isn't right. The thing is, we can remove the clk_put() just because there is no _remove() for that driver. I remember that back in the days the driver was mainlined, clk removal wasn't too easy.
FWIW, as soon as _remove() support will be added by someone, we'll have to rethink passing struct clk* by platform_data or at least double-check if we ever used [of_]clk_get() to obtain it.
Mind to send a patch removing the clk_put() on !IS_ERR and add a proper error path instead? While of_clk_get() is the only calls that need cleanup on error in si5351_dt_parse() we should probably move that calls to the end of this function. Otherwise we'd also have to cleanup on every of_parse_foo() failure.
Sebastian
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