[PATCH v2] mt7601u: check chip version on probe

[Stanislaw Gruszka <sgruszka@redhat.com>]

Since some USB device IDs are duplicated between mt7601u and mt76x0u
devices, check chip version on probe and return error if not match
0x7601.

Don't think this is serious issue, probe most likely will fail at
some other point for wrong device, but we do not have to configure
it if we know is not mt7601u device.

Reported-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
v2: return -ENODEV 
 
 drivers/net/wireless/mediatek/mt7601u/usb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt7601u/usb.c b/drivers/net/wireless/mediatek/mt7601u/usb.c
index d8b7863f7926..be3c794612b2 100644
--- a/drivers/net/wireless/mediatek/mt7601u/usb.c
+++ b/drivers/net/wireless/mediatek/mt7601u/usb.c
@@ -303,6 +303,10 @@ static int mt7601u_probe(struct usb_interface *usb_intf,
 	mac_rev = mt7601u_rr(dev, MT_MAC_CSR0);
 	dev_info(dev->dev, "ASIC revision: %08x MAC revision: %08x\n",
 		 asic_rev, mac_rev);
+	if ((asic_rev >> 16) != 0x7601) {
+		ret = -ENODEV;
+		goto err;
+	}
 
 	/* Note: vendor driver skips this check for MT7601U */
 	if (!(mt7601u_rr(dev, MT_EFUSE_CTRL) & MT_EFUSE_CTRL_SEL))
-- 
1.9.3