Definitely the manager.
I've worked with managers who were OK with us working from home as long as work was getting done.
I also worked with another supervisor who once shouted at me whole I was on the Phone with my wife who was calling from the US....He even pushed me and shouted at me in front of my subordinates........
Then there was this another boss who had cameras installed in different rooms where people used to sit.Every one had to officially "Tell" him that they were leaving for the day......you couldn't leave without permission......
Organizational policies are largely driven by senior professionals.In larger companies, each departmental head can determine how his department works, as long as it is within the broad framework of company policies.
Every company in the world has HR policies that basically emphasize equality, respect and equal opportunity.But in practise, its different.
Basically, and this is my belief, If the supervisor thinks that HR and personnel management are crappy management areas which are no good in terms of determining competitive advantage, he will always run his department like his fiefdom