Subscribing to power manager events.

[kat829]

Hi!

I am trying to subscribe to the power management events that correspond to the following log lines (which I can clearly see in the log):

I: POWER event ready
I: POWER event removed
I: SUSPEND state detected
I: RESUMING from suspend

I have been trying with this code:

#include "power.h"
#include <zephyr/logging/log.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/sys/util.h>
#include <zephyr/pm/device.h>
#include <zephyr/pm/state.h>
#include <zephyr/pm/pm.h>

LOG_MODULE_REGISTER(my_module, LOG_LEVEL_INF);

void pm_notifier_cb(enum pm_state state)
{
    printk("PM: %i", state);
}

static struct pm_notifier notifier = {
    .state_entry = pm_notifier_cb,
    .state_exit = pm_notifier_cb,
};

void InitPower(void) {
    printk("Power Init");
    pm_notifier_register(&notifier);
}

I have extended prj.conf with:

CONFIG_PM_DEVICE_RUNTIME=y
CONFIG_PM_DEVICE=y
CONFIG_PM=y

Results:

• - "Power Init" is getting printed just fine
• - but the callback is never called.

Setup:

• - NCS_VERSION=v2.6.0
• - Running from Ubuntu
• - Any other info needed?

Any idea what I am doing wrong?

[kat829]

I see.

So where do the mentioned POWER log lines come from?

I: POWER event ready
I: POWER event removed

[Vidar Berg]

It's probably from the USB stack here: https://github.com/nrfconnect/sdk-zephyr/blob/1fa31bbc30a3e501a3d6dfce978128a03e61b1e3/drivers/usb/udc/udc_nrf.c#L383.

You can pass a callback function to the usb_enable() function if you want to monitor USB events in your app.

https://docs.nordicsemi.com/bundle/ncs-latest/page/zephyr/connectivity/usb/device/api/usb_device.html#c.usb_enable  

[kat829]

I see.

Our project uses c2usb to handle USB, that in turn uses zephyr's udc. As a result, using usb_enable directly is not possible (it results in multiple registrations for irq 39). I guess I shall delegate this on our usb expert.

If you have any further comments, they are welcome, otherwise I consider this solved.

Thanks for help!

[Vidar Berg]

In that case, it looks like you should be using this function: https://docs.nordicsemi.com/bundle/ncs-latest/page/zephyr/connectivity/usb/device_next/api/usbd.html#c.usbd_msg_register_cb 

[kat829]

(I assume you mean when some version that compiles is released.)

Thanks!