rt2x00: Add dynamic detection of eFuse EEPROM in rt2800pci.

Instead of assuming that all rt3090 devices will have an eFuse EEPROM,
do as the legacy Ralink driver, and detect at run-time whether an
eFuse EEPROM is present.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800pci.c

@@ -145,6 +145,15 @@ static void rt2800pci_read_eeprom_pci(struct rt2x00_dev *rt2x00dev)
 			       EEPROM_SIZE / sizeof(u16));
 }
 
+static int rt2800pci_efuse_detect(struct rt2x00_dev *rt2x00dev)
+{
+	u32 reg;
+
+	rt2800_register_read(rt2x00dev, EFUSE_CTRL, &reg);
+
+	return rt2x00_get_field32(reg, EFUSE_CTRL_PRESENT);
+}
+
 static void rt2800pci_efuse_read(struct rt2x00_dev *rt2x00dev,
 				 unsigned int i)
 {
@@ -182,6 +191,11 @@ static inline void rt2800pci_read_eeprom_pci(struct rt2x00_dev *rt2x00dev)
 {
 }
 
+static inline int rt2800pci_efuse_detect(struct rt2x00_dev *rt2x00dev)
+{
+	return 0;
+}
+
 static inline void rt2800pci_read_eeprom_efuse(struct rt2x00_dev *rt2x00dev)
 {
 }
@@ -1091,11 +1105,11 @@ static int rt2800pci_validate_eeprom(struct rt2x00_dev *rt2x00dev)
 	case RT3052:
 		rt2800pci_read_eeprom_soc(rt2x00dev);
 		break;
-	case RT3090:
-		rt2800pci_read_eeprom_efuse(rt2x00dev);
-		break;
 	default:
-		rt2800pci_read_eeprom_pci(rt2x00dev);
+		if (rt2800pci_efuse_detect(rt2x00dev))
+			rt2800pci_read_eeprom_efuse(rt2x00dev);
+		else
+			rt2800pci_read_eeprom_pci(rt2x00dev);
 		break;
 	}
 

drivers/net/wireless/rt2x00/rt2800pci.h

@@ -62,6 +62,7 @@
 #define EFUSE_CTRL_ADDRESS_IN		FIELD32(0x03fe0000)
 #define EFUSE_CTRL_MODE			FIELD32(0x000000c0)
 #define EFUSE_CTRL_KICK			FIELD32(0x40000000)
+#define EFUSE_CTRL_PRESENT		FIELD32(0x80000000)
 
 /*
  * EFUSE_DATA0