Dallas/Maxim DS1307/37/38/39/40, ST M41T00, EPSON RX-8025

modulename: rtc-ds1307.ko

configname: CONFIG_RTC_DRV_DS1307

Linux Kernel Configuration
└─>Device Drivers
└─>Real Time Clock
└─>I2C support
└─>Dallas/Maxim DS1307/37/38/39/40, ST M41T00, EPSON RX-8025
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
If you say yes here you get support for various compatible RTC
chips (often with battery backup) connected with I2C. This driver
should handle DS1307, DS1337, DS1338, DS1339, DS1340, ST M41T00,
EPSON RX-8025 and probably other chips. In some cases the RTC
must already have been initialized (by manufacturing or a
bootloader).

The first seven registers on these chips hold an RTC, and other
registers may add features such as NVRAM, a trickle charger for
the RTC/NVRAM backup power, and alarms. NVRAM is visible in
sysfs, but other chip features may not be available.

This driver can also be built as a module. If so, the module
will be called rtc-ds1307.

source code: