rt2500usb_bbp_read
bbp = rt2500usb_bbp_read(rt2x00dev, 17);
.read = rt2500usb_bbp_read,
r2 = rt2500usb_bbp_read(rt2x00dev, 2);
r14 = rt2500usb_bbp_read(rt2x00dev, 14);
value = rt2500usb_bbp_read(rt2x00dev, 0);