[PROBLEM] gpio: hog: requesting hog failed

[PROBLEM] gpio: hog: requesting hog failed

[Jiří Prchal]

Hi everybody,
I've just tried new gpio hog functionality, but maybe I misunderstand something
or I'm doing something wrong?
Can someone help me with it, please?
Thanks, Jiri.

Here is dmesg:
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.3.0-rc4-next-20151006_cpm9g25+ (prchal@prchalpc) (gcc version 4.7.3 (Ubuntu/Linaro 
4.7.3-12ubuntu1) ) #7 PREEMPT Thu Oct 8 09:08:21 CEST 2015
[    0.000000] CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=0005317f
...
[    0.243333] requesting hog GPIO in18 (chip fffff400.gpio, offset 28) failed
[    0.243333] requesting hog GPIO in19 (chip fffff400.gpio, offset 21) failed
[    0.246666] gpio-at91 fffff400.gpio: at address c8856400
...

and here my part of dts:
...
	ahb {
		apb {
			pinctrl@fffff400 {
				pioA: gpio@fffff400 {
					in18 {
						gpio-hog;
						gpios = <28 0>;
						input;
						line-name = "in18";
					};
					in19 {
						gpio-hog;
						gpios = <21 GPIO_ACTIVE_LOW>;
						input;
					};
				};
...

Re: [PROBLEM] gpio: hog: requesting hog failed

[Linus Walleij]

On Thu, Oct 8, 2015 at 2:29 PM, Jiří Prchal <jiri.prchal@aksignal.cz> wrote:

> Hi everybody,
> I've just tried new gpio hog functionality, but maybe I misunderstand
> something
> or I'm doing something wrong?
> Can someone help me with it, please?

Sometimes this has something to do with driver probe order.
For example if the driver uses a pin control backend to the GPIO,
it will not be able to request its own GPIOs until after both drivers
have probed.

You need to talk to the maintainers of this driver, J-C, Alexander
Stein, Nicolas Ferre.

Yours,
Linus Walleij
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