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Message-ID: <20180517063640.GK5130@dell>
Date: Thu, 17 May 2018 07:36:40 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Amelie DELAUNAY <amelie.delaunay@...com>
Cc: Linus Walleij <linus.walleij@...aro.org>,
Rob Herring <robh@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>,
Alexandre TORGUE <alexandre.torgue@...com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/5] dt-bindings: pinctrl: document the STMFX pinctrl
bindings
On Wed, 16 May 2018, Amelie DELAUNAY wrote:
>
>
> On 05/16/2018 04:20 PM, Linus Walleij wrote:
> > On Wed, May 9, 2018 at 9:56 AM, Amelie DELAUNAY <amelie.delaunay@...com> wrote:
> >
> >> Indeed, stmfx has other functions than GPIO. But, after comments done
> >> here: [1] and there: [2], it has been decided to move MFD parent/GPIO
> >> child drivers into a single PINCTRL/GPIO driver because of the following
> >> reasons:
> >> - Other stmfx functions (IDD measurement and TouchScreen controller) are
> >> not used on any of the boards using an stmfx and supported by Linux, so
> >> no way to test these functions, and no need to maintain them while they
> >> are not being used.
> >> - But, in the case a new board will use more than GPIO function on
> >> stmfx, the actual implementation allow to easily extract common init
> >> part of stmfx and put it in an MFD driver.
> >>
> >> So I could remove gpio sub-node and put its contents in stmfx node and
> >> keep single PINCTRL/GPIO driver for the time being.
> >> Please advise,
> >
> > I would normally advice to use the right modeling from the start, create
> > the MFD driver and spawn the devices from there. It is confusing
> > if the layout of the driver(s) doesn't really match the layout of the
> > hardware.
> >
> > I understand that it is a pain to write new MFD drivers to get your
> > things going and it would be "nice to get this working really quick
> > now" but in my experience it is better to do it right from the start.
> >
>
> Hi Linus,
>
> Thanks for your advice. I understand the point.
> So, the right modeling would be to:
> - create an MFD driver with the common init part of stmfx
> - remove all common init part of stmfx-pinctrl driver and keep only all
> gpio/pinctrl functions.
>
> I will not develop the other stmfx functions (IDD measurement driver and
> TouchScreen controller driver) because, as explained ealier, they are
> not used on any of the boards using an stmfx and supported by Linux, so
> no way to test these functions, and no need to maintain them while they
> are not being used.
>
> Lee, are you OK with that ?
I missed a lot of this conversation I think, but from what I've read,
it sounds fine.
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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