From mboxrd@z Thu Jan  1 00:00:00 1970
From: kgene.kim@samsung.com (Kukjin Kim)
Date: Mon, 10 Oct 2011 18:58:00 +0900
Subject: [PATCH 1/5] ARM: Samsung: PWM: Allow to differentiate SoCs based
	on platform device name.
In-Reply-To: <20110907190120.GA24703@sirena.org.uk>
References: <1731819.jJi37IsjvJ@flatron> <1660939.8M3FnZsmga@flatron>
	<20110906110311.GM6619@n2100.arm.linux.org.uk>
	<5725201.5LdnvaEu1n@flatron>
	<20110906120430.GO6619@n2100.arm.linux.org.uk>
	<20110907190120.GA24703@sirena.org.uk>
Message-ID: <039e01cc8733$17df3e10$479dba30$%kim@samsung.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Mark Brown wrote:
> 
> On Tue, Sep 06, 2011 at 01:04:30PM +0100, Russell King - ARM Linux wrote:
> 
> > Pros to platform driver name:
> > 1. Can re-use existing names if feature compatible without driver mods.
> > 2. Scales well with an increasing number of SoCs.
> 
> > Cons:
> > 1. People will hate having SoC names which don't refer to their exact
SoC.
> > 2. Probably requires storage of a set of flags in driver private data
> >    to identify SoC specific features.
> > 3. Requires additional string space to identify each driver name.
> 
> There's also an issue with actually getting the devices together to
> register which causes fragility here.
> 
> > However, thinking about this more wrt DT, there's another aspect to
this.
> > Rather than encoding into the driver "this SoC has features and quirks
> > X,Y,Z" maybe that information should be in the device tree itself.  For
> > example, SoC 1 has X and Z, SoC 2 has Y.  Then a new SoC 3 comes along
> > with X and Y but not Z.  If X, Y, Z are encoded into DT then there's no
> > need to touch the kernel to support SoC 3, not even to change driver
> > names or soc_is_xxx macros etc.
> 
> This does depend pretty strongly on making sure that the SoC DT is
> distributed separately to the board DT - that should be solved now.

Yes, I agree. So we can keep the current way to support each SoCs' device
with one driver until DT world.

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.