Level-triggered GPIO interrupt with NCS 2.7 on nRF9160

[SenseJo]

Hi,

after upgrading to NCS v2.7.0, I have some trouble with an increased sleep power consumption of our device when I use Zephyr's gpio-keys for the button input.

I was using NCS v2.5.2 before. Initially after upgrading, the button would not work any more at all, when I would compile with `CONFIG_PM_DEVICE` and `CONFIG_PM_DEVICE_RUNTIME`. That could be resolved by calling `pm_device_runtime_get()` on the gpio-keys device during initialization. Now the button would work, but the sleep power consumption would increase by around 15 μA.

With NCS v2.5.2, I also had an increase of the power consumption by about 15 μA when I added the button with gpio-keys to my software and enabled CONFIG_INPUT.
According to this (old) thread on devzone, the nRF9160 would require the use of level-, not edge-triggered GPIO interrupts, for low power consumption.

I then applied a small fix to the Zephyr gpio-keys driver, to use level-triggered instead of edge-triggered interrupts (see https://github.com/senseing-gmbh/sdk-zephyr/commit/7cab2bf5b45c6edf39632d5d0886781a05aaf50d). With this fix, the sleep power consumption would be good again.

Now, with NCS v2.7.0, simply replacing `GPIO_INT_EDGE_BOTH` in `zephr/drivers/input/input_gpio_keys.c` by `GPIO_INT_LEVELS_LOGICAL` again did not do the trick, though. I also tried `GPIO_INT_LEVEL_ACTIVE`, but then the sleep power consumption is still increased and the button would not work any more.

Is my approach to use `pm_device_runtime_get()` right, and how can I reduce the power consumption again with gpio-keys?

[Charlie]

Hi Johannes, 

Are you sure the 15uA extra current comes from GPIO configuration?

Would you be able to make a small sample only using gpio-keys to compare the power difference?

You can share me the sample if the difference still exists. 

In addition, I share a discussion about System off mode (+) nRF9160 - SYSTEM OFF Mode Current - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com) just in case you are also interested.

Best regards,

Charlie

[SenseJo]

Hi Charlie,

thanks for your reply!

I couldn't find out how to attach source files to this thread, but it's easily reproduceable e.g. with a slight modification of the Zephyr input_dump sample (e.g. from NCS v2.7.0, zephyr/samples/subsys/input/input_dump).

Just add code for initializing the modem to the main function (to work around NCSDK-10106), so it looks as follows:

#include <stdio.h>
#include <modem/nrf_modem_lib.h>

int main(void)
{
    int ret = nrf_modem_lib_init();
    if (ret) {
        printf("ERROR: Modem library initialization failed (%d)", ret);
        return ret;
    }

    printf("Input sample started\n");
    return 0;
}

Then, compile the the sample as follows:

west build -b nrf9160dk/nrf9160/ns (read) -- -DCONFIG_NRF_MODEM_LIB=y -DCONFIG_SERIAL=n

On my board, this results in a sleep current of ~18 μA:

Whereas, when the same sample is build with an additional `-DCONFIG_INPUT_GPIO_KEYS=n`, on my board the sleep current would be around 3 μA:

(I am using a custom board, but it simply consists of an nRF9160, an LDO and a SIM card slot, so I am still using the nrf9160dk/nrf9160/ns target)

[Charlie]

Hi Johannes,

I tried the solution you mentioned before, and the following change will make a nRF9160DK consume around 2.3uA floor current.

C:\NCS\v2.7.0\zephyr\samples\subsys\input\input_dump> git diff
diff --git a/drivers/input/input_gpio_keys.c b/drivers/input/input_gpio_keys.c
index fa27ca5bd64..d666e9c18de 100644
--- a/drivers/input/input_gpio_keys.c
+++ b/drivers/input/input_gpio_keys.c
@@ -149,7 +149,7 @@ static int gpio_keys_interrupt_configure(const struct gpio_dt_spec *gpio_spec,

        LOG_DBG("port=%s, pin=%d", gpio_spec->port->name, gpio_spec->pin);

-       ret = gpio_pin_interrupt_configure_dt(gpio_spec, GPIO_INT_EDGE_BOTH);
+       ret = gpio_pin_interrupt_configure_dt(gpio_spec, GPIO_INT_LEVELS_LOGICAL & ~GPIO_INT_MODE_DISABLED);
        if (ret < 0) {
                LOG_ERR("interrupt configuration failed: %d", ret);
                return ret;
diff --git a/samples/subsys/input/input_dump/prj.conf b/samples/subsys/input/input_dump/prj.conf
index e4c7fb97d5d..e8137283778 100644
--- a/samples/subsys/input/input_dump/prj.conf
+++ b/samples/subsys/input/input_dump/prj.conf
@@ -3,3 +3,4 @@ CONFIG_LOG_MODE_MINIMAL=y
 
 CONFIG_INPUT=y
 CONFIG_INPUT_EVENT_DUMP=y
+CONFIG_SERIAL=n
\ No newline at end of file

Change CONFIG_SERIAL to y and verified that the buttons still work.

*** Booting nRF Connect SDK v2.7.0-5cb85570ca43 ***
*** Using Zephyr OS v3.6.99-100befc70c74 ***
Input sample started
I: input event: dev=buttons          SYN type= 1 code= 11 value=1
I: input event: dev=buttons          SYN type= 1 code= 11 value=0
I: input event: dev=buttons          SYN type= 1 code=  2 value=1
I: input event: dev=buttons          SYN type= 1 code=  2 value=0
I: input event: dev=buttons          SYN type= 1 code= 11 value=1
I: input event: dev=buttons          SYN type= 1 code= 11 value=0
I: input event: dev=buttons          SYN type= 1 code=  2 value=1
I: input event: dev=buttons          SYN type= 1 code=  2 value=0

Do you have a chance to test with an nRF9160DK? 

Best regards,

Charlie