Healthd module

Openvela healthd publishes health detection modules such as battery charging status, charging voltage and current, and battery temperature through uORB. The Healthd module mainly senses the changes of mask through all device nodes in the /dev/charge/ directory under the poll system, obtains the changed parameters and publishes them through uORB.

Battery chip driver

For different battery chip drivers, the following requirements are required for the framework:

1. The device nodes registered by the battery chip need to be in the /dev/charge/ directory.

2. The battery chip driver must implement parameter change perception notification, and support the upper layer to access through poll in the process.

Healthd system framework

The system framework of Healthd is shown in the figure below:

It is mainly divided into 3 parts:

1. Healthd will open all registered charger device nodes and add the device nodes to the monitoring list.
2. Healthd monitors the POLLIN event of the charger device node through poll. If an event occurs, it will read the corresponding mask value and call the ioctl interface through mask to obtain the value of the corresponding change parameter of charger.
3. Healthd calls uORB’s API orb_publish_auto to publish the topic information of the battery status.

Healthd monitoring framework

The poll framework of Healthd is shown in the figure below:

The battery chip mainly registers two types of device nodes:

1. charger device node: mainly monitors changes in battery charging, charging status, charging voltage, charging current, battery temperature, etc.

2. gauge device node: mainly monitors changes in battery charging, battery power, battery temperature, etc.

3. charger device node: mainly monitors changes in battery charging, charging status, charging voltage, charging current, battery temperature, etc.

4. gauge device node: mainly monitors changes in battery presence, battery power, battery temperature, etc.

Healthd code path

Path: frameworks/system/healthd