The RTC driver can drive various real-time clocks and provides an interface for other components, e.g., uvmm, to read and write the time.

It needs access to the hardware, depending on the clock, either via a vbus or via an I2C device.

Command Line Options

There are no command line options.

Environment

Several capabilities can be used to interact with the environment:

• 'rtc' (server)

  The capability with which clients talk to the service. Note that writing to the RTC is only possible when having the rtc capability with write rights, read-only clients must have the capability with read rights only.

• 'vbus'

  The vbus used to access hardware for port-based clock on X86 and pl031 on arm.

  The vbus is also needed for receiving the inhibitor signal from IO.

• 'ds3231' (optional)

  The capability that provides access to an I2C DS3231 device. The capability needs to be created with type 1 (i2c-device).