Can I use my phone's charger to connect arduino M0 pro R3 with computer?
Echoing what Gerben said, in order to wrap up this question:


If the Samsung cable has a micro-usb on one end, and a usb-a on the other side, then I don't see why not. 
You just want to power it, not connect it to a PC? A regular USB port only supplies upto 500mA, so 1.5A is plenty.
The allowed input voltage range for this pin is 6-20 V. source‌​. So your 12v adapter is also fine.