drivers/usb/dwc3/drd.c

   1 /**
   2  * drd.c - DesignWare USB3 DRD Controller Dual-role support
   3  *
   4  * Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com
   5  *
   6  * Authors: Roger Quadros <rogerq@ti.com>
   7  *
   8  * This program is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2  of
  10  * the License as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/extcon.h>
  22
  23 #include "debug.h"
  24 #include "core.h"
  25 #include "gadget.h"
  26
  27 static void dwc3_drd_update(struct dwc3 *dwc)
  28 {
  29         int id;
  30
  31         id = extcon_get_state(dwc->edev, EXTCON_USB_HOST);
  32         if (id < 0)
  33                 id = 0;
  34
  35         dwc3_set_mode(dwc, id ?
  36                       DWC3_GCTL_PRTCAP_HOST :
  37                       DWC3_GCTL_PRTCAP_DEVICE);
  38 }
  39
  40 static int dwc3_drd_notifier(struct notifier_block *nb,
  41                              unsigned long event, void *ptr)
  42 {
  43         struct dwc3 *dwc = container_of(nb, struct dwc3, edev_nb);
  44
  45         dwc3_set_mode(dwc, event ?
  46                       DWC3_GCTL_PRTCAP_HOST :
  47                       DWC3_GCTL_PRTCAP_DEVICE);
  48
  49         return NOTIFY_DONE;
  50 }
  51
  52 int dwc3_drd_init(struct dwc3 *dwc)
  53 {
  54         int ret;
  55
  56         if (dwc->dev->of_node) {
  57                 if (of_property_read_bool(dwc->dev->of_node, "extcon"))
  58                         dwc->edev = extcon_get_edev_by_phandle(dwc->dev, 0);
  59
  60                 if (IS_ERR(dwc->edev))
  61                         return PTR_ERR(dwc->edev);
  62
  63                 dwc->edev_nb.notifier_call = dwc3_drd_notifier;
  64                 ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
  65                                                &dwc->edev_nb);
  66                 if (ret < 0) {
  67                         dev_err(dwc->dev, "couldn't register cable notifier\n");
  68                         return ret;
  69                 }
  70         }
  71
  72         dwc3_drd_update(dwc);
  73
  74         return 0;
  75 }
  76
  77 void dwc3_drd_exit(struct dwc3 *dwc)
  78 {
  79         extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
  80                                    &dwc->edev_nb);
  81
  82         dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
  83         flush_work(&dwc->drd_work);
  84         dwc3_gadget_exit(dwc);
  85 }