rt2x00: Fix vgc_level_reg handling

Currently vgc_level_reg and vgc_level are equal to eachother,
while the purpose of vgc_level_reg is the value last written
to the register and is remembered through link tuning resets.
The vgc_level is the currently active level, which is
reset during link tuning resets.

The usage of these variables depends on the drivers, some drivers
need both, while others need only one of the two.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2400pci.c

@@ -586,9 +586,11 @@ static void rt2400pci_link_stats(struct rt2x00_dev *rt2x00dev,
 static inline void rt2400pci_set_vgc(struct rt2x00_dev *rt2x00dev,
 				     struct link_qual *qual, u8 vgc_level)
 {
-	rt2400pci_bbp_write(rt2x00dev, 13, vgc_level);
-	qual->vgc_level = vgc_level;
-	qual->vgc_level_reg = vgc_level;
+	if (qual->vgc_level_reg != vgc_level) {
+		rt2400pci_bbp_write(rt2x00dev, 13, vgc_level);
+		qual->vgc_level = vgc_level;
+		qual->vgc_level_reg = vgc_level;
+	}
 }
 
 static void rt2400pci_reset_tuner(struct rt2x00_dev *rt2x00dev,

drivers/net/wireless/rt2x00/rt2500pci.c

@@ -626,6 +626,7 @@ static inline void rt2500pci_set_vgc(struct rt2x00_dev *rt2x00dev,
 {
 	if (qual->vgc_level_reg != vgc_level) {
 		rt2500pci_bbp_write(rt2x00dev, 17, vgc_level);
+		qual->vgc_level = vgc_level;
 		qual->vgc_level_reg = vgc_level;
 	}
 }
@@ -700,13 +701,10 @@ static void rt2500pci_link_tuner(struct rt2x00_dev *rt2x00dev,
 	 * R17 is inside the dynamic tuning range,
 	 * start tuning the link based on the false cca counter.
 	 */
-	if (qual->false_cca > 512 && qual->vgc_level_reg < 0x40) {
+	if (qual->false_cca > 512 && qual->vgc_level_reg < 0x40)
 		rt2500pci_set_vgc(rt2x00dev, qual, ++qual->vgc_level_reg);
-		qual->vgc_level = qual->vgc_level_reg;
-	} else if (qual->false_cca < 100 && qual->vgc_level_reg > 0x32) {
+	else if (qual->false_cca < 100 && qual->vgc_level_reg > 0x32)
 		rt2500pci_set_vgc(rt2x00dev, qual, --qual->vgc_level_reg);
-		qual->vgc_level = qual->vgc_level_reg;
-	}
 }
 
 /*

drivers/net/wireless/rt2x00/rt2x00link.c

@@ -302,6 +302,7 @@ void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
 void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
 {
 	struct link_qual *qual = &rt2x00dev->link.qual;
+	u8 vgc_level = qual->vgc_level_reg;
 
 	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
 		return;
@@ -317,6 +318,13 @@ void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
 	rt2x00dev->link.count = 0;
 	memset(qual, 0, sizeof(*qual));
 
+	/*
+	 * Restore the VGC level as stored in the registers,
+	 * the driver can use this to determine if the register
+	 * must be updated during reset or not.
+	 */
+	qual->vgc_level_reg = vgc_level;
+
 	/*
 	 * Reset the link tuner.
 	 */