Re: [PATCH v3] clk: ti: omap36xx: Work around sprz319 advisory 2.1

From: Tero Kristo <t-kristo@ti.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Ladislav Michl <ladis@linux-mips.org>
Cc: <linux-omap@vger.kernel.org>, <linux-clk@vger.kernel.org>,
	Paul Walmsley <paul@pwsan.com>, Richard Watts <rrw@kynesim.co.uk>,
	Tony Lindgren <tony@atomide.com>,
	Alexander Kinzer <a.kinzer@plusoptix.de>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Michael Turquette <mturquette@baylibre.com>
Subject: Re: [PATCH v3] clk: ti: omap36xx: Work around sprz319 advisory 2.1
Date: Mon, 5 Dec 2016 14:24:05 +0200	[thread overview]
Message-ID: <f020ef5f-0f0b-fd4c-d4da-55daa539c3d0@ti.com> (raw)
In-Reply-To: <3176488.xoM6adFiVO@avalon>

On 05/12/16 13:08, Laurent Pinchart wrote:
> Hi Ladislav,
>
> On Monday 05 Dec 2016 10:36:49 Ladislav Michl wrote:
>> On Mon, Dec 05, 2016 at 10:46:43AM +0200, Laurent Pinchart wrote:
>>> On Monday 05 Dec 2016 09:22:10 Ladislav Michl wrote:
>>
>> [snip]
>>
>>>> Table 36 list two options with 26MHz clocks: m=443, n=11 and m=480, n=12
>>>> with a statement: "The choice between these two options with a 26 MHz
>>>> input should be based on characterization on the end system."
>>>>
>>>> Shall we care about that?
>>>
>>> I'd like to, but at the moment I don't see how. Proposals are welcome :-)
>>> I
>>
>> One of proposals raised earlier was DT property, but that idea was scratched
>> later.
>
> It might not be such a bad idea, given that the decision should be made based
> on the characterization of the whole system. One could argue that such
> platform information could have its place in DT.
>
>>> don't think addressing that issue should be a blocker to get this patch
>>> merged though.
>>
>> Of course not. I'd like to even see it in stable ;-)
>>
>> [snip]
>>
>>> I had tried that, but I find the code less readable :-S
>>
>> Oh... Please reconsider (I really do not like that extra test and extra
>> assignment to local variables (also I had 'precomputed' as mixed definition,
>> but Tero did not quite like that)) :-)
>
> I still like to favour code readability when possible (especially when the
> compiler should optimize both versions the same way). I'm not the maintainer
> of this driver though, so I'll let Tero decides what he prefers.

The compiler should ideally generate same size code for these both. 
Personally, I don't mind which version goes in; I'd say both are as 
readable.

Stephen, Mike, is one of you going to pick this up? I don't think I have 
anything else to pull due to the ongoing discussion with the other 
pending stuff.

-Tero

>
>> Also, checked if the same values are written to clk as with my patch, so
>> here's my:
>> Tested-by: Ladislav Michl <ladis@linux-mips.org>
>
> Thank you.
>