I2C ADS 7828 REGISTERS

I have detected th pine i2c input of ads7828 device connected to my beagleboard-xm i2c. Its address is 0x48. Now how do i read the exact value of input coming from the adc? Which register should i read using the command i2cget -y -f 2 0x48 0x?? w so that i could get the voltage input/?

And can i use the i2c input to control the gpio pin output ? Like i want the gpio pin to be “high” when i2c input is less than some value and it should go “low” when i2c input exceeds that value?

plzzz help
Regards