[PATCH] usb: dwc3: st: Propagate reset deassert failures

[Pengpeng Hou]

The ST DWC3 glue driver treats the powerdown and softreset reset
controls as required resources, but ignores reset_control_deassert()
failures before populating the child DWC3 device.  Resume ignores the
same failures before returning success.

Check the deassert operations and unwind the already deasserted
powerdown reset if softreset deassertion fails.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/usb/dwc3/dwc3-st.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-st.c b/drivers/usb/dwc3/dwc3-st.c
index 5d513decaacd..bbabfd933798 100644
--- a/drivers/usb/dwc3/dwc3-st.c
+++ b/drivers/usb/dwc3/dwc3-st.c
@@ -242,7 +242,9 @@ static int st_dwc3_probe(struct platform_device *pdev)
 				     "could not get power controller\n");
 
 	/* Manage PowerDown */
-	reset_control_deassert(dwc3_data->rstc_pwrdn);
+	ret = reset_control_deassert(dwc3_data->rstc_pwrdn);
+	if (ret)
+		return ret;
 
 	dwc3_data->rstc_rst =
 		devm_reset_control_get_shared(dev, "softreset");
@@ -253,7 +255,9 @@ static int st_dwc3_probe(struct platform_device *pdev)
 	}
 
 	/* Manage SoftReset */
-	reset_control_deassert(dwc3_data->rstc_rst);
+	ret = reset_control_deassert(dwc3_data->rstc_rst);
+	if (ret)
+		goto undo_powerdown;
 
 	/* Allocate and initialize the core */
 	ret = of_platform_populate(node, NULL, NULL, dev);
@@ -328,8 +332,15 @@ static int st_dwc3_resume(struct device *dev)
 
 	pinctrl_pm_select_default_state(dev);
 
-	reset_control_deassert(dwc3_data->rstc_pwrdn);
-	reset_control_deassert(dwc3_data->rstc_rst);
+	ret = reset_control_deassert(dwc3_data->rstc_pwrdn);
+	if (ret)
+		return ret;
+
+	ret = reset_control_deassert(dwc3_data->rstc_rst);
+	if (ret) {
+		reset_control_assert(dwc3_data->rstc_pwrdn);
+		return ret;
+	}
 
 	ret = st_dwc3_drd_init(dwc3_data);
 	if (ret) {
-- 
2.50.1 (Apple Git-155)