Ok. I'm not sure why you have not responded to my request for additional information. I asked these questions because they are legally significant to understanding your employment status, which in term, dictates your particular protections. Without the information, I have to speak in generalities and I'm then forced to give a less precise response.
Generally speaking, speaking with HR is not a actually a protected activity. Unlike most are led to believe, HR is actually just an arm of the employer whose primary goal is protecting the company. There is no real anonymity or confidentiality in your comments to HR. So, in an employment situation where you are an "at will" employee and your complaints relate to just workplace issues that would amount to office politics, there is literally no protection at all. You have to be exceedingly careful with what you say, because it can easily backfire on you and form the basis for a termination.
Now, if you are in a contract situation or union, then you are a bit more protected because you can only be terminated for cause, in accordance with the contract. Then you just have to avoid comments that amount to insubordination (just stay professional).
Finally, if you are complaining about discrimination (race, religion, gender, age, disability or recent medical leave use), OSHA matters or wage and hour issues, you have protections from external statutes and again, you just have to remain professional in your comments.