Message-ID: <5701348.MhkbZ0Pkbq@kista>
Date:   Tue, 15 Mar 2022 19:04:05 +0100
From:   Jernej Škrabec <jernej.skrabec@...il.com>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>,
        Cai Huoqing <caihuoqing@...du.com>,
        Chen-Yu Tsai <wens@...e.org>,
        Dinghao Liu <dinghao.liu@....edu.cn>,
        Dmitry Osipenko <digetx@...il.com>,
        Eugen Hristev <eugen.hristev@...rochip.com>,
        Ezequiel Garcia <ezequiel@...guardiasur.com.ar>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Jacopo Mondi <jacopo@...ndi.org>,
        Jia-Ju Bai <baijiaju1990@...il.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Maxime Ripard <mripard@...nel.org>,
        Mikhail Rudenko <mike.rudenko@...il.com>,
        Ming Qian <ming.qian@....com>,
        Ondrej Jirman <megous@...ous.com>,
        Robert Foss <robert.foss@...aro.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
        Yong Deng <yong.deng@...ewell.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org, linux-sunxi@...ts.linux.dev
Subject: Re: Re: [PATCH v2 47/67] media: platform: rename sunxi/ to allwinner/

Dne torek, 15. marec 2022 ob 09:35:05 CET je Laurent Pinchart napisal(a):
> On Tue, Mar 15, 2022 at 09:27:36AM +0100, Mauro Carvalho Chehab wrote:
> > Em Tue, 15 Mar 2022 08:54:25 +0200
> > Laurent Pinchart <laurent.pinchart@...asonboard.com> escreveu:
> > 
> > > Hi Mauro,
> > > 
> > > On Tue, Mar 15, 2022 at 06:40:05AM +0100, Mauro Carvalho Chehab wrote:
> > > > Em Mon, 14 Mar 2022 18:22:20 +0100 Jernej Škrabec escreveu:
> > > >   
> > > > > Dne ponedeljek, 14. marec 2022 ob 17:34:42 CET je Mauro Carvalho 
Chehab 
> > > > > napisal(a):  
> > > > > > As the end goal is to have platform drivers split by vendor,
> > > > > > rename sunxi/ to allwinner/.
> > > > > > 
> > > > > > Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>    
> > > > > 
> > > > > I would rather not do that. Everything related to Allwinner is 
called sunxi, 
> > > > > albeit there are a few outliers. This is similar to Amlogic/meson 
situation.  
> > > > 
> > > > The rationale of having one directory per manufacturer is that, if 
drivers
> > > > for newer platforms with different names from the same manufacturers 
are 
> > > > added, those will still fit under allwinner/ and amlogic/.
> > > > 
> > > > The Kconfig names for sunxi and meson didn't change, nor the driver's 
name. 
> > > > Also, the directories under allwinner preserve sun<x>i name on them:
> > > > 
> > > > 	drivers/media/platform/allwinner/
> > > > 	├── sun4i-csi
> > > > 	├── sun6i-csi
> > > > 	├── sun8i-di
> > > > 	└── sun8i-rotate
> > > > 
> > > > and so the directory under amlogic/:
> > > > 
> > > > 	drivers/media/platform/amlogic/
> > > > 	└── meson-ge2d
> > > > 
> > > > Now, if Allinner decides to release a new platforms named after 
another star,
> > > > let's say, "Vega" and "Rigel", it would be just a matter of adding 
> > > > "vega/" and "rigel/" directories under allwinner. No need to touch
> > > > media/platform/Kconfig and media/platform/Makefile. Everything will 
happen
> > > > on much more smaller vendor-specific Kconfig/Makefile.  
> > > 
> > > But the day Allwinner changes its name to Noloser, we'll have a similar
> > > problem. 
> > 
> > Not really. It will still be a single directory per vendor (whatever
> > name it is).
> > 
> > > Thnk about Freescale vs. NXP, or Altera bought by Intel.
> > 
> > Yeah, when some drivers move from one vendor to another one that
> > already exists there, we should probably move the directories, in
> > order to keep things well organized.
> 
> I'm not sure we should. We still have arch/arm64/boot/dts/freescale/ for
> instance. We can answer that question later though, when confronted with
> the situation.
> 
> > The worse case scenario is really if, let's say, TI decides to sell their
> > omap architecture to NXP, keeping the rest. On such case, the best would
> > be to move platform/ti/omap* to the directory of its newer owner.
> > 
> > That's said, when things like that happen, there are usually a change
> > at MAINTAINERS, as e-mails, mailing lists and contact people will
> > likely change. So, this will very likely generate patches anyway.
> > 
> > > No
> > > naming scheme is totally future-proof. If the accepted standard through
> > > the kernel is to use sunxi to refer to Allwinner SoCs, I don't think
> > > it's a bit idea to go with that.
> > 
> > I'm not too concerned about the name here, but rather about the
> > process. Needing to do reorg like this is painful, as it causes 
> > all pending work to fail merging against upstream, requiring rebases.
> > So, we should avoid needing to re-do it by trying our best to avoid
> > the need of another global change like that in the future.
> 
> Most of the pain we'll go through in the immediate future comes from the
> fact that we never really cared about this. I think renames (of vendors
> or product lines) will be infrequent enough that picking sunxi for
> Allwinner drivers wouldn't be an issue.
> 
> There's a similar think with Renesas, which had an SH product line and
> then moved to ARM, creating R-Mobile and R-Car (among other product
> liens). That's why we still have drivers/dma/sh/ for Renesas DMA
> drivers.
> 
> > By organizing entries per vendor, while we may need to do puntual
> > per-vendor adjustments when they rename and change IP with other
> > vendors, the global platform Kconfig/Make will contain a single entry
> > per vendor. I can't foresee any need to change this in the future,
> > if we take care of keeping the entries there properly sorted.
> > 
> > With regards to naming the per-vendor directory, while I do prefer to have
> > the  directories named after the vendor, and not after a vendor's nick 
> > name, It should also be ok to use a vendor's nick name, provided that 
> > such name is meant to be used by all their current and future IP.
> > 
> > Not sure if "sunxi" is actually a vendor's nick name. It sounds
> > much likely that it is, instead, a brand name that covers their 
> > current media-related SoC. 
> > 
> > Can someone from the vendor shed a light on it?

Allwinner (as a company) isn't directly involved in maintaining upstream Linux 
support. Drivers are provided by linux-sunxi community, sometimes by cleaning 
up vendor drivers or more often by writing them from scratch.

That being said, "sunxi" is extensively used in vendor kernel, most often it's 
directory name containing vendor specific driver. It's derived from SoC family 
name, like sun4i, sun5i, sun5i, sun50i, etc. where number is replaced with X.

sunxi is synonym for Allwinner basically from the start. Community build 
around these SoCs is called linux-sunxi and even entry in MAINTAINERS contains 
both names: "ARM/Allwinner sunXi SoC support". Note that sunxi is not limited 
to ARM SoCs. RISC-V family is called sun20i.

Hope this helps.

Best regards,
Jernej

> 
> Maybe we can let the Allwinner upstream community tell us what name to
> pick ? I'm sure they know better than us :-)



> 
> -- 
> Regards,
> 
> Laurent Pinchart
> 

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