On 14.8.2017 15:55, Linus Walleij wrote:

On Mon, Aug 7, 2017 at 1:01 PM, Michal Simek [off-list ref] wrote:

quoted

From: Nava kishore Manne <redacted>

In general situation on-SoC GPIO controller drivers should be probed
after pinctrl/pinmux controller driver, because on-SoC GPIOs utilize a
pin/pad as a resource provided and controlled by pinctrl subsystem.

  GPIO must come after pinctrl as gpios may need to mux pins....etc

Looking at Xilinx SoC series pinctrl drivers, zynq*_pinctrl_init()
functions are called at arch_initcall init levels,
so the change of initcall level for gpio-zynq driver from
postcore_initcall to subsys_initcall level is sufficient. Also note
that the most of GPIO controller drivers settled at subsys_initcall
level.

If pinctrl subsystem manages pads with GPIO functions, the change is
needed to avoid unwanted driver probe deferrals during kernel boot.

Signed-off-by: Nava kishore Manne <redacted>
Signed-off-by: Michal Simek <redacted>

Can't you just move it all the way to device_initcall and
simply use the standard module init macros?
builtin_platform_driver(), module_platform_driver()?

When I grep the kernel I see this

[linux](master)$ git grep "^core_initcall" drivers/gpio/ | wc -l
1
[linux](master)$ git grep "^postcore_initcall" drivers/gpio/ | wc -l
12
[linux](master)$ git grep "^arch_initcall" drivers/gpio/ | wc -l
2
[linux](master)$ git grep "^subsys_initcall" drivers/gpio/ | wc -l
33
[linux](master)$ git grep "^device_initcall" drivers/gpio/ | wc -l
4


[linux](master)$ git grep "^core_initcall" drivers/pinctrl/ | wc -l
6
[linux](master)$ git grep "^postcore_initcall" drivers/pinctrl/ | wc -l
7
[linux](master)$ git grep "^arch_initcall" drivers/pinctrl/ | wc -l
62
[linux](master)$ git grep "^subsys_initcall" drivers/pinctrl/ | wc -l
12
[linux](master)$ git grep "^device_initcall" drivers/pinctrl/ | wc -l
0

Majority of gpio drivers are in subsys_initcall and pinctrl in
arch_initcall. It doesn't mean that I have strong opinion about doing
this change. I have also read internal tracking system and it is not
fully clear if this is fixing any issue rather than removing on
deferring probe message.

Nava: Do you have any comment?

Thanks,
Michal