ath9k: add spectral scan feature

Adds the spectral scan feature for ath9k. AR92xx and AR93xx chips
are supported for now. The spectral scan is triggered by configuring
a mode through a debugfs control file. Samples can be gathered via
another relay debugfs file.

Essentially, to try it out:

echo chanscan > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl
iw dev wlan0 scan
cat /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan0 > samples
echo disable > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl

This feature is still experimental.

The special "chanscan" mode is used to perform spectral scan while
mac80211 is scanning for channels. To allow this,
sw_scan_start/complete() ops have been added.

The patch contains code snippets and information from Zefir Kurtisi and
information provided by Adrian Chadd and Felix Fietkau.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 5c01f43c32b0..90cfcb3983d1 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -20,6 +20,7 @@
 #include <linux/slab.h>
 #include <linux/ath9k_platform.h>
 #include <linux/module.h>
+#include <linux/relay.h>
 
 #include "ath9k.h"
 
@@ -916,6 +917,11 @@ static void ath9k_deinit_softc(struct ath_softc *sc)
                 sc->dfs_detector->exit(sc->dfs_detector);
 
         ath9k_eeprom_release(sc);
+
+        if (sc->rfs_chan_spec_scan) {
+                relay_close(sc->rfs_chan_spec_scan);
+                sc->rfs_chan_spec_scan = NULL;
+        }
 }
 
 void ath9k_deinit_device(struct ath_softc *sc)