AR_D_GBL_IFS_EIFS
REG_WRITE(ah, AR_D_GBL_IFS_EIFS, 20);
REG_WRITE(ah, AR_D_GBL_IFS_EIFS, 20);
eifs = REG_READ(ah, AR_D_GBL_IFS_EIFS)/
REG_WRITE(ah, AR_D_GBL_IFS_EIFS, ath9k_hw_mac_to_clks(ah, eifs));