[PATCH] usb: mtu3: Don't check the USB3 status bits if the max speed is USB2

[amergnat at baylibre.com]

From: Alexandre Bailon <abailon at baylibre.com>

If the IP is U3, the driver will check some USB3 status bits.
This could fail if only USB2 is used.
This only check these bits if USB operate at USB3 speed.

Signed-off-by: Alexandre Bailon <abailon at baylibre.com>
Signed-off-by: Fabien Parent <fparent at baylibre.com>
Signed-off-by: Alexandre Mergnat <amergnat at baylibre.com>
---
This patch is ported from downstream. Without this fix, USB doesn't
work if USB2 protocol is used first.
---
 drivers/usb/mtu3/mtu3_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/mtu3/mtu3_core.c b/drivers/usb/mtu3/mtu3_core.c
index a3a6282893d0..00dba871aff8 100644
--- a/drivers/usb/mtu3/mtu3_core.c
+++ b/drivers/usb/mtu3/mtu3_core.c
@@ -100,7 +100,7 @@ static int mtu3_device_enable(struct mtu3 *mtu)
 
 	mtu3_clrbits(ibase, U3D_SSUSB_IP_PW_CTRL2, SSUSB_IP_DEV_PDN);
 
-	if (mtu->u3_capable) {
+	if (mtu->u3_capable && mtu->max_speed >= USB_SPEED_SUPER) {
 		check_clk = SSUSB_U3_MAC_RST_B_STS;
 		mtu3_clrbits(ibase, SSUSB_U3_CTRL(0),
 			(SSUSB_U3_PORT_DIS | SSUSB_U3_PORT_PDN |

---
base-commit: fe15c26ee26efa11741a7b632e9f23b01aca4cc6
change-id: 20230426-usb-mtu3-improvement-77d987def9fe

Best regards,
-- 
Alexandre Mergnat <amergnat at baylibre.com>