b43: add helper waiting for given value in radio reg

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43/phy_common.c b/drivers/net/wireless/b43/phy_common.c
index f627cef..f01676a 100644
--- a/drivers/net/wireless/b43/phy_common.c
+++ b/drivers/net/wireless/b43/phy_common.c
@@ -240,6 +240,21 @@
 			  (b43_radio_read16(dev, offset) & mask) | set);
 }
 
+bool b43_radio_wait_value(struct b43_wldev *dev, u16 offset, u16 mask,
+			  u16 value, int delay, int timeout)
+{
+	u16 val;
+	int i;
+
+	for (i = 0; i < timeout; i += delay) {
+		val = b43_radio_read(dev, offset);
+		if ((val & mask) == value)
+			return true;
+		udelay(delay);
+	}
+	return false;
+}
+
 u16 b43_phy_read(struct b43_wldev *dev, u16 reg)
 {
 	assert_mac_suspended(dev);