RE: [PATCH v2] Revert "pinctrl: freescale: imx: Use 'devm_of_iomap()' to avoid a resource leak in case of error in 'imx_pinctrl_probe()'"

[Aisheng Dong <aisheng.dong@xxxxxxx>]

> From: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Sent: Wednesday, June 17, 2020 2:16 AM
> 
> On Tue, Jun 16, 2020 at 5:54 AM Aisheng Dong <aisheng.dong@xxxxxxx>
> wrote:
> 
> > Could you help apply this patch as it blocked MX7D booting for a while?
> 
> > > This reverts commit ba403242615c2c99e27af7984b1650771a2cc2c9.
> > >
> > > After commit 26d8cde5260b ("pinctrl: freescale: imx: add shared
> > > input select reg support"). i.MX7D has two iomux controllers iomuxc
> > > and iomuxc-lpsr which share select_input register for daisy chain settings.
> > > If use 'devm_of_iomap()', when probe the iomuxc-lpsr, will call
> > > devm_request_mem_region() for the region <0x30330000-0x3033ffff> for
> > > the first time. Then, next time when probe the iomuxc, API
> > > devm_platform_ioremap_resource() will also use the API
> > > devm_request_mem_region() for the share region
> > > <0x30330000-0x3033ffff> again, then cause issue, log like below:
> > >
> > > [    0.179561] imx7d-pinctrl 302c0000.iomuxc-lpsr: initialized IMX pinctrl
> > > driver
> > > [    0.191742] imx7d-pinctrl 30330000.pinctrl: can't request region for
> > > resource [mem 0x30330000-0x3033ffff]
> > > [    0.191842] imx7d-pinctrl: probe of 30330000.pinctrl failed with error
> -16
> 
> It means that shared support took a wrong approach. If something has shared
> resources, another schema should be used, something like MFD (parent device
> which keeps only shared resources). Easiest way is to switch to the regmap API.
> 

I think a bit more, probably it's not worth to do it in order to not break current driver design a lot.
LPSR iomux case is bit complicated that only sel input is using the shared memory within another iomuxc.
Current approach seems already the easiest and most clean way.

Regards
Aisheng

> P.S. The revert is okay as a quick fix but... see above.
> 
> --
> With Best Regards,
> Andy Shevchenko