drivers/usb/dwc3/drd.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /**
   3  * drd.c - DesignWare USB3 DRD Controller Dual-role support
   4  *
   5  * Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com
   6  *
   7  * Authors: Roger Quadros <rogerq@ti.com>
   8  */
   9
  10 #include <linux/extcon.h>
  11
  12 #include "debug.h"
  13 #include "core.h"
  14 #include "gadget.h"
  15
  16 static void dwc3_drd_update(struct dwc3 *dwc)
  17 {
  18         int id;
  19
  20         id = extcon_get_state(dwc->edev, EXTCON_USB_HOST);
  21         if (id < 0)
  22                 id = 0;
  23
  24         dwc3_set_mode(dwc, id ?
  25                       DWC3_GCTL_PRTCAP_HOST :
  26                       DWC3_GCTL_PRTCAP_DEVICE);
  27 }
  28
  29 static int dwc3_drd_notifier(struct notifier_block *nb,
  30                              unsigned long event, void *ptr)
  31 {
  32         struct dwc3 *dwc = container_of(nb, struct dwc3, edev_nb);
  33
  34         dwc3_set_mode(dwc, event ?
  35                       DWC3_GCTL_PRTCAP_HOST :
  36                       DWC3_GCTL_PRTCAP_DEVICE);
  37
  38         return NOTIFY_DONE;
  39 }
  40
  41 int dwc3_drd_init(struct dwc3 *dwc)
  42 {
  43         int ret;
  44
  45         if (dwc->dev->of_node) {
  46                 if (of_property_read_bool(dwc->dev->of_node, "extcon"))
  47                         dwc->edev = extcon_get_edev_by_phandle(dwc->dev, 0);
  48
  49                 if (IS_ERR(dwc->edev))
  50                         return PTR_ERR(dwc->edev);
  51
  52                 dwc->edev_nb.notifier_call = dwc3_drd_notifier;
  53                 ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
  54                                                &dwc->edev_nb);
  55                 if (ret < 0) {
  56                         dev_err(dwc->dev, "couldn't register cable notifier\n");
  57                         return ret;
  58                 }
  59         }
  60
  61         dwc3_drd_update(dwc);
  62
  63         return 0;
  64 }
  65
  66 void dwc3_drd_exit(struct dwc3 *dwc)
  67 {
  68         extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
  69                                    &dwc->edev_nb);
  70
  71         dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
  72         flush_work(&dwc->drd_work);
  73         dwc3_gadget_exit(dwc);
  74 }