[PATCH] usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly
From: Krishna Kurapati
Date: Thu Jul 14 2022 - 10:56:23 EST
On SC7180 devices, it is observed that dwc3 probing is deferred
because device_links_check_suppliers() finds that '88e3000.phy'
isn't ready yet.
As a part of its probe call, dwc3-qcom driver checks if dwc3 core
is wakeup capable or not. If the dwc3 core is wakeup capable, driver
configures dwc-qcom's power domain to be always ON. Also it configures
dp/dm interrupts accordingly to support wakeup from system suspend.
More info regarding the same can be found at:
commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status"
commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend")
In the event, dwc3 probe gets deferred and is processed after dwc3-qcom
probe, driver ends up reading the wakeup capability of dwc3 core as false
leading to instability in suspend/resume path.
To avoid this scenario, ensure dwc3_probe is successful by checking
if appropriate driver is assigned to it or not after the of_platform_populate
call. If it isn't then defer dwc3-qcom probe as well.
Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
drivers/usb/dwc3/dwc3-qcom.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index 7703655..096d1414 100644
@@ -722,6 +722,9 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
dev_err(dev, "failed to get dwc3 platform device\n");
+ if (!qcom->dwc3->dev.driver)
+ return -EPROBE_DEFER;