The Linux 5.7 kernel that will be out in the late spring / early summer is poised to see support for USB fast charging support for Apple iOS devices.
Currently if charging an Apple iPhone / iPad from a USB port by default it will not draw more than 500mA per specifications. However, iOS devices can draw more power when communicated to do so via Apple’s protocol. With Linux 5.7 a new “apple-mfi-fastcharge” driver will allow this capability of up to 2500mA.
The apple-mfi-fastcharge driver will allow setting the power supply property via sysfs to “fast” and in turn lets the iOS device draw more power from the USB port, similar to the behavior of MFi certified chargers.
This 200+ lines of code charger written by Bastien Nocera has been queued into USB-next by Greg Kroah-Hartman for introduction in Linux 5.7. To no surprise, this USB fast charging driver for iOS devices was written without the support of Apple. With Linux 5.6 feature work having just ended last weekend, this is one of the first major USB additions that is already queued via the subsystem’s “-next” branch for ultimately landing in the next kernel series.