How many times do I need to do likable actions to get max affinity?

From the Fallout 4 Wiki:

Typically, all companions begin at an affinity value of 0. If the affinity value reaches 500, they will "admire" the Sole Survivor and often reveal new dialogue. Raising their affinity to 1000+ (max is 1100) will result in them "idolizing" the Sole Survivor, at which point the Sole Survivor are granted their companion perk.

You gain/lose this much affinity based upon four different ways a companion perceives an action:

• Liked: +15
• Loved: +35
• Disliked: -15
• Hated: -35

Most companions start at 0, meaning to reach Max affinity of 1,100 you would need to do ~73 "liked" actions (1,100/15), or ~31.5 "loved" actions (1,100/35). Of course you can perform any combination of these actions to reach the max.

If you consider 1,000 to be the max, since reaching 1,100 has no additional benefit besides giving you some wiggle room in the event you perform an action they dislike/hate, then you would need to do ~67 liked actions (1,000/15) or ~26 loved actions (1,000/35).