linux-kernel - Re: [PATCH] clkdev: only fall through to clk_get

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Message-ID: <20140427191238.GE26756@n2100.arm.linux.org.uk>
Date:	Sun, 27 Apr 2014 20:12:38 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Sylwester Nawrocki <sylvester.nawrocki@...il.com>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH] clkdev: only fall through to clk_get_sys() if DT
	indicates no entry

On Sun, Apr 27, 2014 at 09:08:54PM +0200, Sylwester Nawrocki wrote:
> On 04/26/2014 05:49 PM, Russell King wrote:
>> There are two failures which DT can return when looking up a phandle:
>> -ENOENT - when DT finds that the desired property/index is not present
>> -EINVAL - when DT finds that the desired property/index is present, but
>>   there is a problem parsing it.
>>
>> We should only fall through to clk_get_sys() (the table driven clock
>> lookup) when DT indicates that there was no entry in the OF tables
>> for the clock.  Doing otherwise causes the clk API to always indicate
>> that there is no entry for this clock, which is not correct behaviour.
>>
>> Cc: <stable@...r.kernel.org>
>> Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
>> ---
>> Grant, Rob,
>>
>> Please let me know ASAP if this gives you any cause for concern.  This
>> looks to me like a long standing bug which really needs fixing.  Part
>> of the motivation here is similar to Jean-Francois' patch to clkdev
>> which allows a DT specified clock which isn't get present to have
>> clk_get() and friends return -EPROBE_DEFER - again, something that I
>> think really should happen.  Jean-Francois hasn't been able to get
>> much traction for his patch, so let's start with fixing this bug first.
>
> How about upstream commit a34cd4666f3da84228a82f70c94b8d9b692034ea,
> I thought it already solves the issue you're trying to address in
> this patch ?

FFS.  You know, I thought _I_ was the clkdev maintainer, not Mike.

That commit is wrong for the reasons I've stated above.  Why should we
fall through to clk_get_sys() if the DT stuff returns -EINVAL?

Okay, I'll re-spin against that patch and fix this crap.

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