Wake-Up Source - 2020.2 English

Versal ACAP System Software Developers Guide (UG1304)

Document ID
UG1304
Release Date
2020-11-24
Version
2020.2 English

The kernel resumes from the suspend mode when a wake-up event occurs. The following wake-up sources can be used:

UART
If enabled as a wake-up source, a UART input will trigger the kernel to resume from the suspend mode.
Required Kernel Configurations
Same as Suspend
Example Code
To set RTC to wake up the APU after 10 seconds:
$ echo enabled > /sys/devices/platform/amba/ff000000.serial/tty/ttyAMA0/power/wakeup
RTC
If enabled as a wake-up source, the kernel will resume from the suspend mode when the RTC timer expires. Note that the RTC wake-up source is enabled by default.
Required Kernel Configurations
Same as Suspend
Example Code
To wake up the APU on UART input:
$ echo enabled > /sys/devices/platform/amba/ff000000.serial/tty/ttyAMA0/power/wakeup
GPIO
If enabled as a wake-up source, a GPIO event will trigger the kernel to resume from the suspend mode.
Required Kernel Configurations
  • Device Drivers
  • Input device support, [*]
    • Generic input layer (needed for keyboard, mouse, ...) (INPUT [=y])
    • [*] Keyboards (INPUT_KEYBOARD [=y])
    • [*] GPIO Buttons (CONFIG_KEYBOARD_GPIO=y)
    • [*] Polled GPIO buttons
Example Code
To wake up the APU on the GPIO pin:
$ echo enabled > /sys/devices/platform/gpio-keys/power/wakeup