usb: xhci-pci: Add support for reset controllers

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.

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200629161845.6021-6-nsaenzjulienne@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 3feaafe..c26c06e 100644 (file)
--- 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"
@@ -346,6 +347,7 @@ 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) {
@@ -354,6 +356,11 @@ 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->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);
 
@@ -371,6 +378,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
        /* USB 2.0 roothub is stored in the PCI device now. */
        hcd = dev_get_drvdata(&dev->dev);
        xhci = hcd_to_xhci(hcd);
+       xhci->reset = reset;
        xhci->shared_hcd = usb_create_shared_hcd(&xhci_pci_hc_driver, &dev->dev,
                                                 pci_name(dev), hcd);
        if (!xhci->shared_hcd) {
@@ -522,6 +530,8 @@ static int xhci_pci_resume(struct usb_hcd *hcd, bool hibernated)
        struct pci_dev          *pdev = to_pci_dev(hcd->self.controller);
        int                     retval = 0;
 
+       reset_control_reset(xhci->reset);
+
        /* The BIOS on systems with the Intel Panther Point chipset may or may
         * not support xHCI natively.  That means that during system resume, it
         * may switch the ports back to EHCI so that users can use their

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index ea1754f..ac44b62 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1770,6 +1770,8 @@ struct xhci_hcd {
        /* optional clocks */
        struct clk              *clk;
        struct clk              *reg_clk;
+       /* optional reset controller */
+       struct reset_control *reset;
        /* data structures */
        struct xhci_device_context_array *dcbaa;
        struct xhci_ring        *cmd_ring;