[PATCH] ARM: dts: kirkwood: fix pin-muxing of MPP7

[Thomas Petazzoni]

Hello,

On Thu,  4 Jan 2018 17:53:12 +0100, Thomas Petazzoni wrote:
> MPP7 is currently muxed as "gpio", but this function doesn't exist for
> MPP7, only "gpo" is available. This causes the following error:
> 
> kirkwood-pinctrl f1010000.pin-controller: unsupported function gpio on pin mpp7
> pinctrl core: failed to register map default (6): invalid type given
> kirkwood-pinctrl f1010000.pin-controller: error claiming hogs: -22
> kirkwood-pinctrl f1010000.pin-controller: could not claim hogs: -22
> kirkwood-pinctrl f1010000.pin-controller: unable to register pinctrl driver
> kirkwood-pinctrl: probe of f1010000.pin-controller failed with error -22
> 
> So the pinctrl driver is not probed, all device drivers (including the
> UART driver) do a -EPROBE_DEFER, and therefore the system doesn't
> really boot (well, it boots, but with no UART, and no devices that
> require pin-muxing).
> 
> Back when the Device Tree file for this board was introduced, the
> definition was already wrong. The pinctrl driver also always described
> as "gpo" this function for MPP7. However, between Linux 4.10 and 4.11,
> a hog pin failing to be muxed was turned from a simple warning to a
> hard error that caused the entire pinctrl driver probe to bail
> out. This is probably the result of commit 6118714275f0a ("pinctrl:
> core: Fix pinctrl_register_and_init() with pinctrl_enable()").
> 
> This commit fixes the Device Tree to use the proper "gpo" function for
> MPP7, which fixes the boot of OpenBlocks A7, which was broken since
> Linux 4.11.
> 
> Fixes: f24b56cbcd9d ("ARM: kirkwood: add support for OpenBlocks A7 platform")
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>

I just realized that my commit title isn't that great, as it doesn't
mention the board. Something like:

	ARM: dts: kirkwood: fix pin-muxing of MPP7 on OpenBlocks A7

would have been better.

Grégory: let me know if you want me to send a v2, or if you can fix up
this while applying.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com