CONFIG_CLKSRC_PXA (not configurable)

modulename: timer-pxa.ko

and/or

pxa_timer.ko

configname: CONFIG_CLKSRC_PXA

Linux Kernel Configuration
└─>Device Drivers
└─>Clock Source drivers
└─>CLKSRC_PXA
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables OST0 support available on PXA and SA-11x0
platforms.

source code:
drivers/clocksource/pxa_timer.c