Some atypical users of xhci-pci might need to manually reset their xHCI
controller before starting the HCD setup. Check if a reset controller
device is available to the PCI bus and trigger a reset.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulie...@suse.de>

---

Changes since v1:
 - Use proper reset API
 - Make code simpler

 drivers/usb/host/xhci-pci.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ef513c2fb843..6e96affa4ceb 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/acpi.h>
+#include <linux/reset.h>
 
 #include "xhci.h"
 #include "xhci-trace.h"
@@ -339,6 +340,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct 
pci_device_id *id)
        struct xhci_hcd *xhci;
        struct usb_hcd *hcd;
        struct xhci_driver_data *driver_data;
+       struct reset_control *reset;
 
        driver_data = (struct xhci_driver_data *)id->driver_data;
        if (driver_data && driver_data->quirks & XHCI_RENESAS_FW_QUIRK) {
@@ -347,6 +349,11 @@ static int xhci_pci_probe(struct pci_dev *dev, const 
struct pci_device_id *id)
                        return retval;
        }
 
+       reset = devm_reset_control_get_optional_exclusive(&dev->bus->dev, NULL);
+       if (IS_ERR(reset))
+               return PTR_ERR(reset);
+       reset_control_reset(reset);
+
        /* Prevent runtime suspending between USB-2 and USB-3 initialization */
        pm_runtime_get_noresume(&dev->dev);
 
-- 
2.26.2

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