Power subsystem overview

Power supply Charger (gpio-charger) Board poweroff and restart

Power (overview)

RT-Thread splits power into several layers. They are related but not interchangeable:

Layer	Page	Scope
Regulator	Regulator	Shared rails (LDO/DCDC): enable, voltage, refcount
Power domain	Power domain	SoC power islands while system is running
Power supply	Power supply	Battery/charger reporting (rt_power_supply)
Board off/restart	Board poweroff and restart	GPIO/syscon shutdown and reset
System DM power	System power off and reboot (core)	Ordered **rt_dm_power_off_handler** + machine hooks

Reset controller (IP block reset lines) is a different subsystem: Reset controller — not under components/drivers/power/reset/.

Sources under **components/drivers/power/**:

Path	Role
**supply/**	rt_power_supply core, daemon, **gpio-charger**, emulator

| ** eset/** | gpio-poweroff, gpio-restart, **syscon-*** reboot/poweroff |

Power domain providers: components/drivers/pmdomain/ (see Power domain).

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Typical consumer <tt>probe</tt> order

When a platform device comes up (Platform bus):

pinctrl (bus)
    → clock defaults (bus)
    → power domain attach (bus)     [optional, -RT_EEMPTY OK]
    → IOMMU attach (bus)            [optional]
    → driver probe:
          regulator get/enable      [your driver]
          reset deassert / clk enable
          rt_dm_dev_iomap
          register functional device

For battery/charger UI or PM policy, drivers register **rt_power_supply** (see Power supply).

For whole-system power off / reboot, drivers register **rt_dm_power_off_handler** (see Board poweroff and restart, System power off and reboot (core)).

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Kconfig (<tt>components/drivers/power/</tt>)

Option	Role
**RT_USING_POWER_SUPPLY**	Power supply class + workqueue
**RT_POWER_SUPPLY_DAEMON**	Poll/notify policy thread
**RT_POWER_SUPPLY_CHARGER_GPIO**	**gpio-charger**
**RT_POWER_SUPPLY_EMU**	Test battery/charger
**RT_USING_POWER_RESET**	Board poweroff/restart drivers
**RT_POWER_RESET_GPIO_***, **RT_POWER_RESET_SYSCON_***	In-tree reset drivers

Regulator and power domain have separate Kconfig trees under **components/drivers/regulator/** and **core/power_domain.c**.

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Quick map: what to implement

Goal	Register / API
Report SOC, charging, USB online	**rt_power_supply_register** + **RT_PLATFORM_DRIVER_EXPORT**
Shutdown PMIC / assert poweroff GPIO	**rt_dm_power_off_handler(..., SHUTDOWN, ...)**
Warm reset / recovery mode	**rt_dm_power_off_handler(..., RESET, ...)** + **rt_dm_reboot_mode_register**
Keep an IP block powered	**rt_dm_power_domain_attach** / **rt_regulator_get**
Share 3.3 V rail	**rt_regulator_enable** / **put**

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See also

• Platform bus — device/driver binding
• PIN Device — GPIO for chargers and gpio-poweroff
• components/drivers/power/Kconfig