From mboxrd@z Thu Jan  1 00:00:00 1970
From: shawn.guo@linaro.org (Shawn Guo)
Date: Mon, 9 Jan 2012 14:32:12 +0800
Subject: [RFC PATCH v3 3/5] pinctrl: imx: add pinctrl imx driver
In-Reply-To: <20120109021702.GV2414@b20223-02.ap.freescale.net>
References: <1324402840-32451-1-git-send-email-b29396@freescale.com>
 <1324402840-32451-4-git-send-email-b29396@freescale.com>
 <20120108130542.GC2203@richard-laptop>
 <20120109020848.GF1835@S2101-09.ap.freescale.net>
 <20120109021702.GV2414@b20223-02.ap.freescale.net>
Message-ID: <20120109063136.GI1835@S2101-09.ap.freescale.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Jan 09, 2012 at 10:17:03AM +0800, Richard Zhao wrote:
> On Mon, Jan 09, 2012 at 10:08:51AM +0800, Shawn Guo wrote:
> > On Sun, Jan 08, 2012 at 09:05:44PM +0800, Richard Zhao wrote:
> > > > +enum imx_imx53_pinctrl_pads {
> > > > +	MX53_GPIO_19 = 0,
> > > > +	MX53_KEY_COL0 = 1,
> > > > +	MX53_KEY_ROW0 = 2,
> > > > +	MX53_KEY_COL1 = 3,
> > > > +	MX53_KEY_ROW1 = 4,
> > > > +	MX53_KEY_COL2 = 5,
> > > > +	MX53_KEY_ROW2 = 6,
> > > ...
> > > Why not describe it in dts and make this file generic for imx?
> > > One node for one pad,
> > 
> > Doing this will bloat the device tree dramatically.  Actually I had
> > a patch doing so before the pinctrl subsystem was born, but it
> > concerned Grant a lot for that reason and thus died.
> are you against describing pad in dts or one node per pad?
> one node per pad is just a tip to extend pad property, to support
> other features (pinconf in your word).

I definitely want to describe pinconf in device tree, though what's
the best interface for pinctrl client driver to talk to pinconf is
still vague to me.

> > 
> > > it'll be easy to extend pad properties. You know
> > > the pad may set pull up/down, open drain, drive strenth, daisy chain etc.
> > > The features have to be supported, to make your model usefull.
> > > 
> > As Aisheng mentioned, the pinconf support will be added later.
> I expect pinconf come together, and get a ready-to-use patch series.
> 
As I was educated by Linus.W, we can not drink ocean and we need to
split big chunk of work into pieces and achieve it step by step.

-- 
Regards,
Shawn