NXP PCF50633 RTC

modulename: rtc-pcf50633.ko

configname: CONFIG_RTC_DRV_PCF50633

Linux Kernel Configuration
└─>Device Drivers
└─>Real Time Clock
└─>NXP PCF50633 RTC
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
If you say yes here you get support for the RTC subsystem of the
NXP PCF50633 used in embedded systems.

source code:
drivers/rtc/rtc-pcf50633.c