wake up from sleep on gpio interrupt

[pratyushtomar]

I am using imx6ul evk with yocto. Once my evk goes to sleep I want to wake it up once interrupt is received on gpio2 21. I added following lines to my dts file

gpio-keys {

    compatible = "gpio-keys";

    wakeup {

      label = "wakeup gpio";

      gpios = <&gpio2 21 GPIO_ACTIVE_LOW>;

      linux,code = <29>;

      gpio-key,wakeup;

    };

  };

I suspend using following command

echo standby > /sys/power/state

but it doesn't wake up once interrupt(high to low) is received on gpio2 21. Where I am making a mistake? Can anyone help me find out reason for failure to wake up?

[vinothkumars]

Hi Pratyush Tomar,

Will you please give your configuration. I am also struggling in wake up.

Thanks & Regards,

VinothS,

[nitigupta]

Hello, 

Currently I am working on wandboard quad. I also want one of its external GPIO act as a Power Button in order to wake up the processor. With this respect, I find this post very useful. But I failed to interpret this line "linux,code = <29>" . From where we get this "linux,code = <29>". Kindly help.

Thanks,

Niti Gupta

[jran]

If you take a look in the kernel documentation /devicetree/bindings/gpio/gpio_keys.txt you will find:

Subnode properties:

- gpios: OF device-tree gpio specification.
- label: Descriptive name of the key.
- linux,code: Keycode to emit.

i.e. what keyboard button the GPIO should correspond to. 

A list of Linux keycodes can be found for example here:

Keycode Table 

Where you can see that keycode 29 is "Left CTRL", which is suitable as it would not have any noticeable effect when it is "pressed" for the wakeup event.

[pratyushtomar]

Hello Carl,

My dts file configuration was correct. The problem was with motion sensor which was not generating interrupt (wake up source from sleep). Secondly as you said the error was due to pin being used twice for 2 different functions.

Thanks

Pratyush

[pratyushtomar]

ok I managed to work out thing my device resumes from sleep but I receive following error messages

root@imx6ulevk:~# imx6ul-pinctrl 20e0000.iomuxc: pin MX6UL_PAD_SD1_DATA3 already requested by 20e0000.iomuxc; cannot claim for 2190000.usdhc

imx6ul-pinctrl 20e0000.iomuxc: pin-116 (2190000.usdhc) status -22

imx6ul-pinctrl 20e0000.iomuxc: could not request pin 116 (MX6UL_PAD_SD1_DATA3) from group usdhc1grp  on device 20e0000.iomuxc

sdhci-esdhc-imx 2190000.usdhc: Error applying setting, reverse things back

[carlsherratt]

Hi Pratyush,

The errors you are seeing relate to some of the pin's defined in your Device Tree being used twice for two different functions.

Can I ask, How did you manage to "work out things" with your suspend/resume issue with the gpio-keys gpio, what was wrong and how did you fix it? It would be useful for the community to explain.

Thanks

Carl

[pratyushtomar]

Hello Yuri I have already gone through these links but it didn't workout. I mad following changes in my dts file.

gpio-keys { 

    compatible = "gpio-keys"; 

    wakeup { 

      label = "wakeup gpio"; 

      gpios = <&gpio2 21 GPIO_ACTIVE_LOW>; 

      linux,code = <29>; 

      gpio-key,wakeup; 

    }; 

  }

imx6ul-evk {

  pinctrl_hog_1: hoggrp-1 {

  fsl,pins = <

  MX6UL_PAD_UART1_RTS_B__GPIO1_IO19 0x17059 /* SD1 CD */

  MX6UL_PAD_GPIO1_IO05__USDHC1_VSELECT 0x17059 /* SD1 VSELECT */

  MX6UL_PAD_GPIO1_IO09__GPIO1_IO09        0x17059 /* SD1 RESET */

  MX6UL_PAD_SNVS_TAMPER0__GPIO5_IO00 0x80000000

  MX6UL_PAD_SD1_DATA3__GPIO2_IO21 0x80000000  //line added

  >;

  };

But it's still not working out.

[Yuri · Accepted solution]

Hello,

  Please refer to the following :

i.MX6 wakeup difficulties

GPIO Line - Wakeup - Level Trigger

How to configure iMX6 (Linux) to power resume via GPIO 

Have a great day,

Yuri

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