linux-kernel - Re: [PATCH 9/9] clocksource: dw_apb_timer: special variant for rockchip rk3188 timers

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Message-ID: <alpine.DEB.2.02.1307062233480.32106@ionos.tec.linutronix.de>
Date:	Sat, 6 Jul 2013 23:00:30 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Ulrich Prinz <ulrich.prinz@...glemail.com>
cc:	Heiko Stübner <heiko@...ech.de>,
	John Stultz <john.stultz@...aro.org>,
	Jamie Iles <jamie@...ieiles.com>,
	Dinh Nguyen <dinguyen@...era.com>,
	Grant Likely <grant.likely@...aro.org>,
	linux-arm-kernel@...ts.infradead.org,
	Rob Herring <rob.herring@...xeda.com>,
	devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>
Subject: Re: [PATCH 9/9] clocksource: dw_apb_timer: special variant for
 rockchip rk3188 timers

Ulrich,

On Sat, 6 Jul 2013, Ulrich Prinz wrote:

> I got the message. With modifying the existing driver to support more
> function pointers in its system struct and assigning them at the
> beginning, and using them on runtime, these quirks are obsolete.

Correct.
 
> Again, this is the first time I provide code to the kernel officially

No problem. That's what code review is about. First post or not.

> and I learned from others that I should try it by modifying not too much
> code if not needed.
> 
> Adding more function pointers to a system relevant structure, doubling
> the number of functions and such didn't look non-invasive to me.

Well, it always depends. If there is a single place to deal with some
oddball hardware, a flag is often the simplest way to go.

If you have to add 10 conditionals in several functions then in a
first step converting the existing implementation into function
pointer calls and then in the next step providing new implementations
for your hardware is most of the time simpler and cleaner.

> But, I totally agree with your argumentation and I even wanted to do it
> in the way you explained in your replies. Just the courage was missing I
> guess :)

Gut feelings are often a better guidance than our self-doubting
intellect. :)

But don't worry. I had to learn it the hard way as well and I still
trip over from time to time.

Thanks,

	tglx
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