AM625: How to use a GPIO on the Main domain as wakeup source

Part Number: AM625

Hello,

according to the release notes, from release 09.00.00, it should be possible to wake the SoC from low power mode using a GPIO in the main domain using I/O Daisy Chain.

Can you provide an example on how this needs to be configured on the device tree?

At the moment we have something like this

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&main_pmx0 {
  pin: main-gpio0-32-pins-default {
    pinctrl-single,pins = <
      AM62X_IOPAD(0x0084, PIN_INPUT_PULLUP, 7)
    >;
  };
};
gpio-keys {
  compatible = "gpio-keys";
  pinctrl-names = "default";
  pinctrl-0 = <&pin>;
  key-wakeup {
    gpios = <&main_gpio0 32 GPIO_ACTIVE_LOW>;
    label = "Wake-Up";
    linux,code = <KEY_WAKEUP>;
    wakeup-source;
  };
};
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

&main_pmx0 {

  pin: main-gpio0-32-pins-default {
    pinctrl-single,pins = <
      AM62X_IOPAD(0x0084, PIN_INPUT_PULLUP, 7)
    >;
  };
};

gpio-keys {
  compatible = "gpio-keys";
  pinctrl-names = "default";
  pinctrl-0 = <&pin>;

  key-wakeup {
    gpios = <&main_gpio0 32 GPIO_ACTIVE_LOW>;
    label = "Wake-Up";
    linux,code = <KEY_WAKEUP>;
    wakeup-source;
  };
};

What do we need to add/change?

over 2 years ago

0 Bin Liu over 2 years ago

TI__Guru**** 153671 points

Hi,

Please see the section 3.2.2.11.5.2. (MCU GPIO) and 3.2.2.11.5.3 (Main UART I/O Daisy Chain) in the documentation below.

https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/09_00_00_03/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Power_Management/pm_wakeup_sources.html

0 fd over 2 years ago in reply to Bin Liu

Intellectual 665 points

Can you please me point out where the solution is described in the page you linked? I cannot find anything related to GPIO on the MAIN domain.

0 Bin Liu over 2 years ago in reply to fd

TI__Guru**** 153671 points

I haven't got a chance to test this by myself, but the mentioned second section explains how to set I/O daisy chain for main_uart0, using interrupts-extended DT property, this should be applicable to MAIN GPIO too.

0 fd over 2 years ago in reply to Bin Liu

Intellectual 665 points

What should I do exactly? I cannot see how that would work for a GPIO. Are you sure that this functionality is working?

0 Bin Liu over 2 years ago in reply to fd

TI__Guru**** 153671 points

I see the interrupts DT entry is different in main_gpioX from main_uartX. I will look into it to see how exactly to configure I/O daisy chain for main gpio. I will get back to you in a few days.

+1 Bin Liu over 2 years ago in reply to fd

TI__Guru**** 153671 points

Hi,

MAIN GPIO wakeup is indeed not supported in SDK9.0 yet. The kernel community just posted a kernel patch laster last week to the gpio-key driver which is needed to enable MAIN GPIO wakeup.

Is there any reason your project picks MAIN GPIO instead of MCU GPIO as the wakeup source?

0 fd over 2 years ago in reply to Bin Liu

Intellectual 665 points

> Is there any reason your project picks MAIN GPIO instead of MCU GPIO as the wakeup source?

The reason is that MCU GPIO bank cannot be shared between the cortex-A and the cortex-M, given we needed to have GPIOs available to the Cortex-M we could not use those as wakeup. At the same time we got a clear answer from TI that this was fine and was going to be supported.

0 fd over 2 years ago in reply to Bin Liu

Intellectual 665 points

Patch is available here: https://lore.kernel.org/all/20230811110432.3968-2-tony@atomide.com/

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AM625: How to use a GPIO on the Main domain as wakeup source