[PATCH v1 2/6] drivers: usb: dwc3: Add delay after core soft reset

[Balaji Selvanathan]

Add a 100 ms delay after clearing the core soft reset bit to ensure
the DWC3 controller has sufficient time to complete its reset
sequence before subsequent register accesses.

Without this delay, USB initialization can fail on some Qualcomm
platforms, particularly when using super-speed capable PHYs like
the QMP USB3-DP Combo PHY on SC7280/QCM6490.

The change is taken from following upstream Linux implementation:
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/dwc3/core.c?id=3d25d46a255a83f94d7d4d4216f38aafc8e116b0

Signed-off-by: Balaji Selvanathan <balaji.selvanathan at oss.qualcomm.com>
---
 drivers/usb/dwc3/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 847fa1f82c3..ff0bca0dd8e 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -94,6 +94,8 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
 	reg &= ~DWC3_GCTL_CORESOFTRESET;
 	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
 
+	mdelay(100);
+
 	return 0;
 }
 
-- 
2.34.1