Man page 9 : device_for_each_child

device_for_each_child - device child iterator.

int device_for_each_child(struct device *  parent , void *  data , int (* fn ) (struct device *dev, void *data));

parent
    parent struct device.

data
    data for the callback.

fn
    function to be called for each device.

Iterate over parentAqs child devices, and call fn for each, passing it data.

We check the return of fn each time. If it returns anything other than 0, we break out and return that value.