Hi,
I've got the same problem. And the problem is RTFM :) According to documentation (https://datasheets.maximintegrated.com/en/ds/DS1302.pdf) DS1302 dos not use i2c. It is using "simple serial protocol". You can find an example here: http://codelectron.com/setting-up-ds1302-rtc-geekcreit-kit-with-orange-pi-zero/
greetings,
Michał