Synchronous Point-to-Point Protocol (PPP) support

modulename: hdlc_ppp.ko

configname: CONFIG_HDLC_PPP

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Wan interfaces support
└─>Synchronous Point-to-Point Protocol (PPP) support
In linux kernel since version 2.6.12  
Generic HDLC driver supporting PPP over WAN connections.

If unsure, say N.

source code:
drivers/net/wan/hdlc_ppp.c