ath5k: use noise calibration from madwifi hal

This updates ath5k to calibrate the noise floor similar to the
way it is done in the madwifi hal and ath9k.  Of note:

- we start NF measurement at the same time as AGC calibration,
  but do not actually read the value until the periodic (long)
  calibration
- we keep a history of the last few values read and write the
  median back to the hardware for CCA
- we do not complain if NF calibration isn't complete, instead
  we keep the last read value.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath5k/attach.c b/drivers/net/wireless/ath/ath5k/attach.c
index 92995adeb5c..42284445b75 100644
--- a/drivers/net/wireless/ath/ath5k/attach.c
+++ b/drivers/net/wireless/ath/ath5k/attach.c
@@ -331,6 +331,8 @@ int ath5k_hw_attach(struct ath5k_softc *sc)
 
 	ath5k_hw_rfgain_opt_init(ah);
 
+	ath5k_hw_init_nfcal_hist(ah);
+
 	/* turn on HW LEDs */
 	ath5k_hw_set_ledstate(ah, AR5K_LED_INIT);