Atheros ath9k/ath9k_htc spectral scan support
configname: CONFIG_ATH9K_COMMON_SPECTRAL
Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Wireless LAN
└─>Atheros ath9k/ath9k_htc spectral scan support
In linux kernel since version 4.2 (release Date: 2015-08-30)
Say Y to enable access to the FFT/spectral data via debugfs.