UART (H4) protocol support

configname: CONFIG_BT_HCIUART_H4

Linux Kernel Configuration
└─>Networking
└─>Bluetooth subsystem support
└─>Bluetooth device drivers
└─>UART (H4) protocol support
In linux kernel since version 2.6.12  
UART (H4) is serial protocol for communication between Bluetooth
device and host. This protocol is required for most Bluetooth devices
with UART interface, including PCMCIA and CF cards.

Say Y here to compile support for HCI UART (H4) protocol.