ath9k: separate debugfs support from CONFIG_ATH_DEBUG

In my setups, ath9k's debugfs files are most of the time much more
useful than the messages generated by enabling CONFIG_ATH_DEBUG along
with the right debug flags.
Since CONFIG_ATH_DEBUG comes with a noticeable overhead on embedded
systems, this patch makes it possible to use the debugfs files without
that option.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/Kconfig

@@ -23,17 +23,12 @@ config ATH9K
 
 	  If you choose to build a module, it'll be called ath9k.
 
-if ATH_DEBUG
-
-config ATH9K_DEBUG
+config ATH9K_DEBUGFS
 	bool "Atheros ath9k debugging"
 	depends on ATH9K
 	---help---
-	  Say Y, if you need ath9k to display debug messages.
-	  Pass the debug mask as a module parameter:
-
-	  modprobe ath9k debug=0x00000200
+	  Say Y, if you need access to ath9k's statistics for
+	  interrupts, rate control, etc.
 
-	  Look in ath9k/debug.h for possible debug masks
+	  Also required for changing debug message flags at run time.
 
-endif # ATH_DEBUG

drivers/net/wireless/ath/ath9k/Makefile

@@ -7,7 +7,7 @@ ath9k-y +=	beacon.o \
 
 ath9k-$(CONFIG_PCI) += pci.o
 ath9k-$(CONFIG_ATHEROS_AR71XX) += ahb.o
-ath9k-$(CONFIG_ATH9K_DEBUG) += debug.o
+ath9k-$(CONFIG_ATH9K_DEBUGFS) += debug.o
 
 obj-$(CONFIG_ATH9K) += ath9k.o
 

drivers/net/wireless/ath/ath9k/ath9k.h

@@ -486,7 +486,7 @@ struct ath_softc {
 
 	int beacon_interval;
 
-#ifdef CONFIG_ATH9K_DEBUG
+#ifdef CONFIG_ATH9K_DEBUGFS
 	struct ath9k_debug debug;
 #endif
 	struct ath_beacon_config cur_beacon_conf;

drivers/net/wireless/ath/ath9k/debug.c

@@ -31,6 +31,8 @@ static int ath9k_debugfs_open(struct inode *inode, struct file *file)
 	return 0;
 }
 
+#ifdef CONFIG_ATH_DEBUG
+
 static ssize_t read_file_debug(struct file *file, char __user *user_buf,
 			     size_t count, loff_t *ppos)
 {
@@ -71,6 +73,8 @@ static const struct file_operations fops_debug = {
 	.owner = THIS_MODULE
 };
 
+#endif
+
 static ssize_t read_file_dma(struct file *file, char __user *user_buf,
 			     size_t count, loff_t *ppos)
 {
@@ -563,10 +567,12 @@ int ath9k_init_debug(struct ath_hw *ah)
 	if (!sc->debug.debugfs_phy)
 		goto err;
 
+#ifdef CONFIG_ATH_DEBUG
 	sc->debug.debugfs_debug = debugfs_create_file("debug",
 		S_IRUSR | S_IWUSR, sc->debug.debugfs_phy, sc, &fops_debug);
 	if (!sc->debug.debugfs_debug)
 		goto err;
+#endif
 
 	sc->debug.debugfs_dma = debugfs_create_file("dma", S_IRUSR,
 				       sc->debug.debugfs_phy, sc, &fops_dma);

drivers/net/wireless/ath/ath9k/debug.h

@@ -23,13 +23,13 @@
 struct ath_txq;
 struct ath_buf;
 
-#ifdef CONFIG_ATH9K_DEBUG
+#ifdef CONFIG_ATH9K_DEBUGFS
 #define TX_STAT_INC(q, c) sc->debug.stats.txstats[q].c++
 #else
 #define TX_STAT_INC(q, c) do { } while (0)
 #endif
 
-#ifdef CONFIG_ATH9K_DEBUG
+#ifdef CONFIG_ATH9K_DEBUGFS
 
 /**
  * struct ath_interrupt_stats - Contains statistics about interrupts
@@ -186,6 +186,6 @@ static inline void ath_debug_stat_retries(struct ath_softc *sc, int rix,
 {
 }
 
-#endif /* CONFIG_ATH9K_DEBUG */
+#endif /* CONFIG_ATH9K_DEBUGFS */
 
 #endif /* DEBUG_H */