Date: Tue, 9 Jan 2018 15:33:29 +0100
From: Gary Bisson <gary.bisson@boundarydevices.com>
To: Stefan Agner <stefan@agner.ch>
Cc: linus.walleij@linaro.org, shawnguo@kernel.org,
        kernel@pengutronix.de, fabio.estevam@nxp.com, aisheng.dong@nxp.com,
        robh+dt@kernel.org, mark.rutland@arm.com,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Arvind Yadav <arvind.yadav.cs@gmail.com>
Subject: Re: [PATCH v2 1/5] pinctrl: imx: use struct imx_pinctrl_soc_info as
 a const
Message-ID: <20180109143329.GA23576@t450s.lan>
References: <20180106142553.15322-1-stefan@agner.ch>
 <20180106142553.15322-2-stefan@agner.ch>
 <20180108164855.GA6504@t450s.lan>
 <f12aa7b7b3aea7a691a1acd14b8daa58@agner.ch>
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Hi Stefan,

On Mon, Jan 08, 2018 at 09:52:36PM +0100, Stefan Agner wrote:
> On 2018-01-08 17:48, Gary Bisson wrote:
> > Hi Stefan,
> > 
> > On Sat, Jan 06, 2018 at 03:25:49PM +0100, Stefan Agner wrote:
> >> For some SoCs the struct imx_pinctrl_soc_info is passed through
> >> of_device_id.data which is const. Most variables are already const
> >> or otherwise not written. However, some fields are modified at
> >> runtime. Move those fields to the dynamically allocated struct
> >> imx_pinctrl.
> >>
> >> Fixes: b3060044e495 ("pinctrl: freescale: imx7d: make of_device_ids const")
> >> Cc: Shawn Guo <shawnguo@kernel.org>
> >> Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
> >> Cc: Dong Aisheng <aisheng.dong@nxp.com>
> >> Cc: Gary Bisson <gary.bisson@boundarydevices.com>
> >> Signed-off-by: Stefan Agner <stefan@agner.ch>
> > 
> > This is actually more or less a revert of a previous commit:
> > b28742be4709 pinctrl: imx: remove const qualifier of imx_pinctrl_soc_info
> 
> Hm, I see. However, back then imx_pinctrl_probe still consumed a
> non-const struct imx_pinctrl_soc_info pointer. So this constifies all
> the way through. 
> 
> > 
> > Note that the idea for this commit was to get dt-overlays working and
> > able to do pinctrl changes using configfs interface to load an overlay
> > (using Pantelis patch). Not sure where we stand on loading such overlay
> > from user-space, is it still something that will happen?
> 
> I am all for dt-overlays and actually also hope that it will make it
> completely into mainline. So whatever prevents using device tree
> overlays should be addressed.
> 
> It seems that ngroups is now part of struct pinctrl_dev (num_groups),
> which is still writable. So we should be fine?

Correct, I forgot about the generic pinmux/pinctrl patches. Indeed
having the structure as const is perfectly fine now, even with
dt-overlays in mind.

Regards,
Gary