[PATCH v2] usb: dwc3: qcom: Provide stubs for dwc3_qcom_read_usb2_speed function

[Krishna Kurapati]

Dwc3 Qcom driver makes use of usb_hub_find_child API in its efforts
to get speed of connected devices (HS/LS/FS) and enable interrupts
accordingly. usb_hub_find_child API is a part of usb core compiled
either into the kernel or as a module (CONFIG_USB= Y or M). In some
builds (make randconfig for i386) CONFIG_USB is not enabled and the
usb core is not compiled resulting in linking errors.

Provide stubs for dwc3_qcom_read_usb2_speed function to use
usb_hub_find_child API only if CONFIG_USB is enabled. Else return
USB_SPEED_UNKNOWN.

Fixes: 6895ea55c385 (usb: dwc3: qcom: Configure wakeup interrupts during suspend)
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Suggested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
---
v2: Updated commit text to include cases when CONFIG_USB=m as well.

 drivers/usb/dwc3/dwc3-qcom.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index c5e482f..bd8dc5a 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -299,6 +299,7 @@ static void dwc3_qcom_interconnect_exit(struct dwc3_qcom *qcom)
 	icc_put(qcom->icc_path_apps);
 }
 
+#ifdef CONFIG_USB
 static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom)
 {
 	struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
@@ -318,6 +319,12 @@ static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom)
 
 	return udev->speed;
 }
+#else
+static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom)
+{
+	return USB_SPEED_UNKNOWN;
+}
+#endif
 
 static void dwc3_qcom_enable_wakeup_irq(int irq, unsigned int polarity)
 {
-- 
2.7.4