Has the U.S. Ever been charged with violating human rights, according to the Geneva Convention?

Not charged, but...

On January 11, 2002, the United States announced that it was refusing to abide by the 1949 Geneva Convention on the treatment of prisoners of war. The Third Geneva Convention, which provides specific guidelines for treatment of prisoner combatants, is a part of the "law of nations" and is a mainstay of international humanitarian law. The United States explained that the prisoners taken in Afghanistan and Pakistan were not actually prisoners of war, but were in fact "unlawful combatants."

- Baltimore Chronicle, February 6, 2002

And BTW, it's not "the Geneva Convention," there are four of them:

The first three Geneva Conventions were revised, expanded, and replaced, and the fourth one was added, in 1949.

• The Geneva Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field was adopted in 1864. It was significantly revised and replaced by the 1906 version the 1929 version, and later the Fourth Geneva Convention of 1949.
  
• The Geneva Convention for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea was adopted in 1906. It was significantly revised and replaced by the Fourth Geneva Convention of 1949.
  
• The Geneva Convention relative to the Treatment of Prisoners of War was adopted in 1929. It was significantly revised and replaced by the Fourth Geneva Convention of 1949.
  
• The Fourth Geneva Convention relative to the Protection of Civilian Persons in Time of War was adopted in 1949.
  

With three Geneva Conventions revised and adopted, and the fourth added, in 1949 the whole set is referred to as the "Geneva Conventions of 1949" or simply the "Geneva Conventions". The treaties of 1949 were ratified, in whole or with reservations, by 196 countries.

- Wikipedia