Re: [RFC PATCH 0/9] initial support for "suniv" Allwinner new ARM9 SoC

From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Icenowy Zheng <icenowy@aosc.io>
Cc: Chen-Yu Tsai <wens@csie.org>,
	Russell King <linux@armlinux.org.uk>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	linux-gpio@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [RFC PATCH 0/9] initial support for "suniv" Allwinner new ARM9 SoC
Date: Mon, 22 Jan 2018 13:14:35 +0100	[thread overview]
Message-ID: <20180122121435.bpayxk4uzfqbhqse@flea.lan> (raw)
In-Reply-To: <20180119231735.61504-1-icenowy@aosc.io>

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On Sat, Jan 20, 2018 at 07:17:26AM +0800, Icenowy Zheng wrote:
> This is the RFC initial patchset for the "new" Allwinner SUNIV ARM9 SoC.
> 
> The same die is packaged differently, come with different co-packaged
> DRAM or shipped with different SDK; and then made many model names: F23,
> F25, F1C100A, F1C100S, F1C200S, F1C500, F1C600, R6, etc. These SoCs all
> share a common feature set and are packaged similarly (eLQFP128 for SoCs
> without co-packaged DRAM, QFN88 for with DRAM). As their's no
> functionality hidden on the QFN88 models (except DRAM interface not
> exported), it's not clever to differentiate them. So I will use suniv as
> common name of all these SoCs.

Where is that suniv prefix coming from?

And you need to have a SoC in all your compatibles. This isn't about
being clever or not, this is just a matter of being able to accurately
read in a crystal ball. Or maybe it's just the same, in which case,
I'd really like to have a course :)

You should really answer two questions here:
  - Are you able to predict whether you'll find an SoC part of that
    family in the future that derives a bit and will need a compatible
    of its own?
  - Are you able to predict which quirks we'll need along the way to
    support all the SoCs you've listed there?

If you can't answer yes to both these questions, with a 100%
certainty, then you'll need a SoC name in the compatible.

Which doesn't prevent you from sharing as much as possible the DT like
we did between the A10s and the A13 for example.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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