Re: PXA25x: GPIO driver fails probe due to resource conflict with pinctrl driver

Jonathan Neuschäfer
2022-12-07T16:40:56Z

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On Wed, Dec 07, 2022 at 04:28:07PM +0100, Andrew Lunn wrote:
> On Wed, Dec 07, 2022 at 12:25:53PM +0100, Jonathan Neuschäfer wrote:
> > Hello,
> >
> > I am currently trying to bring up Linux 6.1-rcX on a PXA255 board, using a
> > devicetree. One problem I encountered is that the PXA GPIO driver fails to
> > probe because it uses the same MMIO register range as the pinctrl driver:
> >
> > [ 0.666169] pxa25x-pinctrl 40e00054.pinctrl: initialized pxa2xx pinctrl driver
> > [ 0.694407] pxa-gpio 40e00000.gpio: can't request region for resource [mem 0x40e00000-0x40e0ffff]
> > [ 0.695050] pxa-gpio: probe of 40e00000.gpio failed with error -16
> >
> > Before I try to fix this myself: Is GPIO on PXA25x currently expected to
> > work and when has it last been seen working?
> >
> > What would be a good way to fix this?
>
> How are the registers arranged? Is 0x40e00000-0x40e0ffff simply too
> large, and making it smaller would fix the issue? Or are the registers
> interleaved? It is possible to request a region in a non-exclusive
> manor. Or is it more than interleaving, individual registers need to
> be shared between the two drivers? If so, you have the locking issues
> you mentioned.
>
> Andrew

(I wrote this before I saw the other reply, so there are probably
duplicate information)

They overlap. pxa25x.dtsi declares:

pinctrl: pinctrl@40e00000 {
reg = <0x40e00054 0x20>, // base_af[0]
<0x40e0000c 0xc>, // base_dir[0]
<0x40e0010c 4>, // base_dir[3]
<0x40f00020 0x10>; // base_sleep[0]
compatible = "marvell,pxa25x-pinctrl";
};

(comments mine, based on pinctrl-pxxa25x.c)

The GPIO driver mentions these registers (for PXA25x):

GPLR GPDR GPSR GPCR GRER GFER GEDR
BANK 0 - 0x0000 0x000C 0x0018 0x0024 0x0030 0x003C 0x0048
BANK 1 - 0x0004 0x0010 0x001C 0x0028 0x0034 0x0040 0x004C
BANK 2 - 0x0008 0x0014 0x0020 0x002C 0x0038 0x0044 0x0050

So, there are overlaps in GPDR (0x0c-0x14, GPIO pin direction register).

The register at 0x10c seems bogus for PXA25x: gpio-pxa.c mentions it as
part of bank 3, which only exists in PXA27x or later.

Jonathan

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