nPM2100 - break-to-wake

[pdrzycimski_apo]

Hello everyone,

We are currently working on a project that uses the nPM2100 to power an nRF52840. Our application requires automatic enabling break-to-wake mode each time the SHPHLD pin is shorted (power switch based on the state of the SHPHLD pin)

At the moment, in our firmware (NCS 3.2.3), we are able to configure the controller through the overlay, but we do not see any way to enable this mode.

npm2100_pmic: pmic@74 {
    compatible = "nordic,npm2100";
    reg = <0x74>;


    shiphold-longpress = "ship";
    // shiphold-current = "low";
    // shiphold-hibernate-wakeup;

    npm2100_gpio: gpio-controller {
        compatible = "nordic,npm2100-gpio";
        gpio-controller;
        #gpio-cells = <2>;
        ngpios = <2>;
    };

    npm2100_regulators: regulators {
        compatible = "nordic,npm2100-regulator";

        npm2100_boost: BOOST {
            regulator-always-on;
            regulator-min-microvolt = <1800000>;
            regulator-max-microvolt = <3300000>;

            regulator-init-microvolt = <3300000>;
            regulator-init-microamp = <300000>;
            regulator-initial-mode = <(NPM2100_REG_OPER_AUTO | NPM2100_REG_FORCE_PASS)>;
            mode-gpios = <&npm2100_gpio 0 (GPIO_ACTIVE_LOW  | GPIO_PULL_DOWN | NPM2100_GPIO_DEBOUNCE_OFF)>;
        };


        npm2100_ldosw: LDOSW {
            regulator-min-microvolt = <800000>;
            regulator-max-microvolt = <3000000>;




            regulator-initial-mode = <(NPM2100_REG_OPER_ULP | NPM2100_REG_LDSW_EN)>;
            mode-gpios = <&npm2100_gpio 0 (GPIO_ACTIVE_HIGH  | GPIO_PULL_DOWN | NPM2100_GPIO_DEBOUNCE_OFF)>;
        };

    };

    npm2100_wdt: watchdog {
        compatible = "nordic,npm2100-wdt";
    };

    npm2100_vbat: vbat {
        compatible = "nordic,npm2100-vbat";
    };
};

Is it possible to configure break-to-wake mode using only the devicetree? I reviewed the driver itself and found options such as:

// shiphold-flags = <x>;
// shiphold-current = "low";
// shiphold-hibernate-wakeup;

Unfortunately, these do not seem to allow switching the mode itself.

If not, is there any example code available that enables it over I2C from the microcontroller? If I understand it correctly, I could use a callback from the SHPHLD pin and manually put the controller into break-to-wake mode.

Thank you in advance for any help. Perhaps someone has run into the same problem and managed to solve it.

Best regards,

Paweł

[Menon]

Hello,

I’m not 100% sure, but I think break-to-wake cannot be configured using only the devicetree. The DT options like shiphold-flags and shiphold-current seem to configure the default SHPHLD behavior (such as pull-up and polarity), but they do not actually switch the PMIC into that mode. See SHPHLD register and  WAKEUP register

Entering break-to-wake requires a runtime step, where the firmware ensures that SHPHLD is in the correct state and then writes to TASKS_SHIP over I2C. Based on this, your approach seems correct, you would need to handle this in firmware, for example by reacting to the SHPHLD pin or your switch logic and then triggering Ship mode manually.  See Ship and break to wake mode

Kind Regards,

Abhijith

[pdrzycimski_apo]

Thank you for your reply. I had read that section of the documentation, but I was hoping there would be some configuration option.

Today I worked on enabling this mode manually, and I managed to do it by writing the following values to the registers:

SHPHLD -> 0x15
WAKEUP -> 0x01
TASKS_SHIP -> 0x01

According to the documentation, I should have set SHPHLD to the option “No resistor” | “Low pull-up current”, but unfortunately that did not allow the PMIC to wake up. The “Weak pull-up enabled” option helped.

dtsi:

npm2100_pmic: pmic@74 {
        compatible = "nordic,npm2100";
        reg = <0x74>;

        shiphold-longpress = "disable";

        //shiphold-flags = <5>;
        //shiphold-current = "low";
        //shiphold-hibernate-wakeup;

        npm2100_gpio: gpio-controller {
            compatible = "nordic,npm2100-gpio";
            gpio-controller;
            #gpio-cells = <2>;
            ngpios = <2>;
        };

        npm2100_regulators: regulators {
            compatible = "nordic,npm2100-regulator";

            npm2100_boost: BOOST {
                regulator-always-on;
                regulator-min-microvolt = <1800000>;
                regulator-max-microvolt = <3300000>;


                regulator-init-microvolt = <1800000>;
                regulator-init-microamp = <300000>;
                
                
            };


            npm2100_ldosw: LDOSW {
                regulator-min-microvolt = <800000>;
                regulator-max-microvolt = <3000000>;
 
                
                
                
                regulator-initial-mode = <(NPM2100_REG_OPER_AUTO | NPM2100_REG_LDSW_EN)>;
                mode-gpios = <&npm2100_gpio 0 (GPIO_ACTIVE_HIGH  | GPIO_PULL_DOWN | NPM2100_GPIO_DEBOUNCE_OFF)>;
            };

        };

        npm2100_wdt: watchdog {
            compatible = "nordic,npm2100-wdt";
        };

        npm2100_vbat: vbat {
            compatible = "nordic,npm2100-vbat";
        };
   };

I have not checked the current consumption in this configuration yet, but functionally it works as expected.

Best Regards,

Paweł