See after a long search, there are no colleges I got which have allowed the use of smartphones. As per most of the colleges, the things a student should keep in mind is that the student should not talk loud, loiter unnecessarily, use of phones are prohibited.

The top PU colleges in Bangalore are:

• Gr Pre University College.
• The Sports School.
• Aurinko Academy.
• The Aurinko Academy Pu College.
• Navkis Residential Pre-university College.
• Shree Swaminarayan Gurukul Residential Pu College.
• Ashok Composite Pu College.
• Sgpta Pu College.

To know more about PUC, visit the link below:

https://school.careers360.com/exams/karnataka-puc-board

I hope this answer helps. All the very best for your future endeavors!