Samsung, one of chipmaker Qualcomm’s largest customers, and Intel, one of its biggest competitors, have added their support to the Federal Trade Commission’s case against Qualcomm.

The FTC’s lawsuit accuses Qualcomm of trying to corner the market for semiconductors used in smartphones. Both firms argue that the company stops them from competing fairly against it by leveraging patents that cover the fundamentals of modern phone systems.

Qualcomm is trying to fend off a series of legal and regulatory challenges to its business practices around the world, including a massive lawsuit by Apple. The chipmaker gets most of its profits from selling the rights to use patents that are used in most mobile phone systems.