A power capping framework has been proposed for the mainline Linux kernel to provide some standard interfaces for the increasing amount of drivers/hardware that support power monitoring and limiting.
More and more Linux hardware device drivers are becoming able to report their own individual power consumption (or estimated at least), some devices are able to set power limits on the device to not exceed a certain power consumption or threshold, and other features with regard to dynamic power control and maximizing performance in a power efficient driver. The Linux power capping framework is intended to provide a unified interface for userspace over sysfs for devices to expose their power capping functionality and to also have a unified driver API for implementing such features.
One example of a power capping driver already found on Linux is the Intel PowerClamp driver
and its RAPL support
Those wanting to find out more details on this proposed power capping framework can find a description along with the initial patch-set on the Linux kernel mailing list