What: /sys/class/power_supply/twl4030_ac/max_current
      /sys/class/power_supply/twl4030_usb/max_current
Description:
	Read/Write limit on current which may
	be drawn from the ac (Accessory Charger) or
	USB port.

	Value is in micro-Amps.

	Value is set automatically to an appropriate
	value when a cable is plugged or unplugged.

	Value can the set by writing to the attribute.
	The change will only persist until the next
	plug event.  These event are reported via udev.