drivers/usb/chipidea/otg.c

   1 /*
   2  * otg.c - ChipIdea USB IP core OTG driver
   3  *
   4  * Copyright (C) 2013 Freescale Semiconductor, Inc.
   5  *
   6  * Author: Peter Chen
   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 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 /*
  14  * This file mainly handles otgsc register, OTG fsm operations for HNP and SRP
  15  * are also included.
  16  */
  17
  18 #include <linux/usb/otg.h>
  19 #include <linux/usb/gadget.h>
  20 #include <linux/usb/chipidea.h>
  21
  22 #include "ci.h"
  23 #include "bits.h"
  24 #include "otg.h"
  25 #include "otg_fsm.h"
  26
  27 /**
  28  * hw_read_otgsc returns otgsc register bits value.
  29  * @mask: bitfield mask
  30  */
  31 u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
  32 {
  33         struct ci_hdrc_cable *cable;
  34         u32 val = hw_read(ci, OP_OTGSC, mask);
  35
  36         /*
  37          * If using extcon framework for VBUS and/or ID signal
  38          * detection overwrite OTGSC register value
  39          */
  40         cable = &ci->platdata->vbus_extcon;
  41         if (!IS_ERR(cable->edev)) {
  42                 if (cable->changed)
  43                         val |= OTGSC_BSVIS;
  44                 else
  45                         val &= ~OTGSC_BSVIS;
  46
  47                 cable->changed = false;
  48
  49                 if (cable->state)
  50                         val |= OTGSC_BSV;
  51                 else
  52                         val &= ~OTGSC_BSV;
  53         }
  54
  55         cable = &ci->platdata->id_extcon;
  56         if (!IS_ERR(cable->edev)) {
  57                 if (cable->changed)
  58                         val |= OTGSC_IDIS;
  59                 else
  60                         val &= ~OTGSC_IDIS;
  61
  62                 cable->changed = false;
  63
  64                 if (cable->state)
  65                         val |= OTGSC_ID;
  66                 else
  67                         val &= ~OTGSC_ID;
  68         }
  69
  70         return val;
  71 }
  72
  73 /**
  74  * hw_write_otgsc updates target bits of OTGSC register.
  75  * @mask: bitfield mask
  76  * @data: to be written
  77  */
  78 void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
  79 {
  80         hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
  81 }
  82
  83 /**
  84  * ci_otg_role - pick role based on ID pin state
  85  * @ci: the controller
  86  */
  87 enum ci_role ci_otg_role(struct ci_hdrc *ci)
  88 {
  89         enum ci_role role = hw_read_otgsc(ci, OTGSC_ID)
  90                 ? CI_ROLE_GADGET
  91                 : CI_ROLE_HOST;
  92
  93         return role;
  94 }
  95
  96 void ci_handle_vbus_change(struct ci_hdrc *ci)
  97 {
  98         if (!ci->is_otg)
  99                 return;
 100
 101         if (hw_read_otgsc(ci, OTGSC_BSV))
 102                 usb_gadget_vbus_connect(&ci->gadget);
 103         else
 104                 usb_gadget_vbus_disconnect(&ci->gadget);
 105 }
 106
 107 #define CI_VBUS_STABLE_TIMEOUT_MS 5000
 108 static void ci_handle_id_switch(struct ci_hdrc *ci)
 109 {
 110         enum ci_role role = ci_otg_role(ci);
 111
 112         if (role != ci->role) {
 113                 dev_dbg(ci->dev, "switching from %s to %s\n",
 114                         ci_role(ci)->name, ci->roles[role]->name);
 115
 116                 ci_role_stop(ci);
 117
 118                 if (role == CI_ROLE_GADGET)
 119                         /* wait vbus lower than OTGSC_BSV */
 120                         hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0,
 121                                         CI_VBUS_STABLE_TIMEOUT_MS);
 122
 123                 ci_role_start(ci, role);
 124         }
 125 }
 126 /**
 127  * ci_otg_work - perform otg (vbus/id) event handle
 128  * @work: work struct
 129  */
 130 static void ci_otg_work(struct work_struct *work)
 131 {
 132         struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
 133
 134         if (ci_otg_is_fsm_mode(ci) && !ci_otg_fsm_work(ci)) {
 135                 enable_irq(ci->irq);
 136                 return;
 137         }
 138
 139         pm_runtime_get_sync(ci->dev);
 140         if (ci->id_event) {
 141                 ci->id_event = false;
 142                 ci_handle_id_switch(ci);
 143         } else if (ci->b_sess_valid_event) {
 144                 ci->b_sess_valid_event = false;
 145                 ci_handle_vbus_change(ci);
 146         } else
 147                 dev_err(ci->dev, "unexpected event occurs at %s\n", __func__);
 148         pm_runtime_put_sync(ci->dev);
 149
 150         enable_irq(ci->irq);
 151 }
 152
 153
 154 /**
 155  * ci_hdrc_otg_init - initialize otg struct
 156  * ci: the controller
 157  */
 158 int ci_hdrc_otg_init(struct ci_hdrc *ci)
 159 {
 160         INIT_WORK(&ci->work, ci_otg_work);
 161         ci->wq = create_freezable_workqueue("ci_otg");
 162         if (!ci->wq) {
 163                 dev_err(ci->dev, "can't create workqueue\n");
 164                 return -ENODEV;
 165         }
 166
 167         if (ci_otg_is_fsm_mode(ci))
 168                 return ci_hdrc_otg_fsm_init(ci);
 169
 170         return 0;
 171 }
 172
 173 /**
 174  * ci_hdrc_otg_destroy - destroy otg struct
 175  * ci: the controller
 176  */
 177 void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
 178 {
 179         if (ci->wq) {
 180                 flush_workqueue(ci->wq);
 181                 destroy_workqueue(ci->wq);
 182         }
 183         /* Disable all OTG irq and clear status */
 184         hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
 185                                                 OTGSC_INT_STATUS_BITS);
 186         if (ci_otg_is_fsm_mode(ci))
 187                 ci_hdrc_otg_fsm_remove(ci);
 188 }