[PATCH] usb: roles: Add PM callbacks

From: Chen, Hu
Date: Sun Jul 07 2019 - 22:44:56 EST


On some Broxton NUC, the usb role is lost after S3 (it becomes "none").
Add PM callbacks to address this issue: save the role during suspend and
restore usb to that role during resume.

Test:
Run Android on UC6CAY, a NUC powered by Broxton. Access this NUC via
"adb shell" from a host PC. After a suspend/resume cycle, the adb still
works well.

Signed-off-by: Chen, Hu <hu1.chen@xxxxxxxxx>
Signed-off-by: Balaji <m.balaji@xxxxxxxxx>

diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
index 277de96181f9..caa1cfab41cc 100644
--- a/drivers/usb/roles/intel-xhci-usb-role-switch.c
+++ b/drivers/usb/roles/intel-xhci-usb-role-switch.c
@@ -37,6 +37,7 @@
struct intel_xhci_usb_data {
struct usb_role_switch *role_sw;
void __iomem *base;
+ enum usb_role role;
};

static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
@@ -167,6 +168,30 @@ static int intel_xhci_usb_remove(struct platform_device *pdev)
return 0;
}

+static int intel_xhci_usb_suspend(struct platform_device *pdev,
+ pm_message_t state)
+{
+ struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+
+ data->role = intel_xhci_usb_get_role(dev);
+
+ return 0;
+}
+
+static int intel_xhci_usb_resume(struct platform_device *pdev)
+{
+ struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+
+ if (intel_xhci_usb_get_role(dev) != data->role) {
+ if (intel_xhci_usb_set_role(dev, data->role) != 0)
+ dev_warn(dev, "Failed to set role during resume\n");
+ }
+
+ return 0;
+}
+
static const struct platform_device_id intel_xhci_usb_table[] = {
{ .name = DRV_NAME },
{}
@@ -180,6 +205,8 @@ static struct platform_driver intel_xhci_usb_driver = {
.id_table = intel_xhci_usb_table,
.probe = intel_xhci_usb_probe,
.remove = intel_xhci_usb_remove,
+ .suspend = intel_xhci_usb_suspend,
+ .resume = intel_xhci_usb_resume,
};

module_platform_driver(intel_xhci_usb_driver);
--
2.22.0