Don't think you can take electronic equipment in there.
You may be able to use one in the common room.
You do what ever they tell you to do.
In a mental hospital how do you buy stuff outside the hospital. Will you have space to put a computer In your room and keep it there if you bought it. What do you do most of the day and what work you do?
If your locked up in their its like jail. They make the rules.
You are not allowed electronics. You are there to work on your mental health. You go to therapy sessions, meditate, learn coping skills and if you need medication they can observe how well it is working to see if they need to adjust the dose or change it all together.
It mainly depends on why you are there. Was it voluntary, or were you committed? And what are you supposed to be getting treatment for?
If it's voluntary, you are normally allowed more "leeway" in outside interactions.
But if you're being treated for something like "internet addiction", any use of technology related to that will be strictly monitored and controlled.