[PATCH AUTOSEL 4.14 18/22] usb: bdc: Halt controller on suspend

[Sasha Levin]

From: Danesh Petigara <danesh.petigara@xxxxxxxxxxxx>

[ Upstream commit 5fc453d7de3d0c345812453823a3a56783c5f82c ]

GISB bus error kernel panics have been observed during S2 transition
tests on the 7271t platform. The errors are a result of the BDC
interrupt handler trying to access BDC register space after the
system's suspend callbacks have completed.

Adding a suspend hook to the BDC driver that halts the controller before
S2 entry thus preventing unwanted access to the BDC register space during
this transition.

Signed-off-by: Danesh Petigara <danesh.petigara@xxxxxxxxxxxx>
Signed-off-by: Al Cooper <alcooperx@xxxxxxxxx>
Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/gadget/udc/bdc/bdc_core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/bdc/bdc_core.c b/drivers/usb/gadget/udc/bdc/bdc_core.c
index 2660cc2e42a08..58ba04d858bab 100644
--- a/drivers/usb/gadget/udc/bdc/bdc_core.c
+++ b/drivers/usb/gadget/udc/bdc/bdc_core.c
@@ -613,9 +613,14 @@ static int bdc_remove(struct platform_device *pdev)
 static int bdc_suspend(struct device *dev)
 {
 	struct bdc *bdc = dev_get_drvdata(dev);
+	int ret;
 
-	clk_disable_unprepare(bdc->clk);
-	return 0;
+	/* Halt the controller */
+	ret = bdc_stop(bdc);
+	if (!ret)
+		clk_disable_unprepare(bdc->clk);
+
+	return ret;
 }
 
 static int bdc_resume(struct device *dev)
-- 
2.25.1