You are looking at the wrong place. The TPM is a very standard piece of hardware, that shouldn’t even need firmware (it would completely cancel the entire point of it). It enables a whole lot of shit, but it isn’t the thing that does the shit.
Now, you can go look at the always-on network enabled uncontrollable management unity that exists inside your computer’s processor… Intel pinky swears they can’t access them in any way and will only activate them if you pay extra¹; AMD AFAIK doesn’t even try to say anything.
1 - Makes sense to you? Well, how do they activate it if they can’t access it?