Re: [PATCH v2 1/5] pinctrl: imx: use struct imx_pinctrl_soc_info as a const

[Gary Bisson]

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@xxxxxxxxxx>
> >> Cc: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
> >> Cc: Dong Aisheng <aisheng.dong@xxxxxxx>
> >> Cc: Gary Bisson <gary.bisson@xxxxxxxxxxxxxxxxxxx>
> >> Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
> > 
> > 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