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         return hw_read(ci, OP_OTGSC, mask);
  34 }
  35
  36 /**
  37  * hw_write_otgsc updates target bits of OTGSC register.
  38  * @mask: bitfield mask
  39  * @data: to be written
  40  */
  41 void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
  42 {
  43         hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
  44 }
  45
  46 /**
  47  * ci_otg_role - pick role based on ID pin state
  48  * @ci: the controller
  49  */
  50 enum ci_role ci_otg_role(struct ci_hdrc *ci)
  51 {
  52         enum ci_role role = hw_read_otgsc(ci, OTGSC_ID)
  53                 ? CI_ROLE_GADGET
  54                 : CI_ROLE_HOST;
  55
  56         return role;
  57 }
  58
  59 void ci_handle_vbus_change(struct ci_hdrc *ci)
  60 {
  61         if (!ci->is_otg)
  62                 return;
  63
  64         if (hw_read_otgsc(ci, OTGSC_BSV))
  65                 usb_gadget_vbus_connect(&ci->gadget);
  66         else
  67                 usb_gadget_vbus_disconnect(&ci->gadget);
  68 }
  69
  70 #define CI_VBUS_STABLE_TIMEOUT_MS 5000
  71 static void ci_handle_id_switch(struct ci_hdrc *ci)
  72 {
  73         enum ci_role role = ci_otg_role(ci);
  74
  75         if (role != ci->role) {
  76                 dev_dbg(ci->dev, "switching from %s to %s\n",
  77                         ci_role(ci)->name, ci->roles[role]->name);
  78
  79                 ci_role_stop(ci);
  80                 /* wait vbus lower than OTGSC_BSV */
  81                 hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0,
  82                                 CI_VBUS_STABLE_TIMEOUT_MS);
  83                 ci_role_start(ci, role);
  84         }
  85 }
  86 /**
  87  * ci_otg_work - perform otg (vbus/id) event handle
  88  * @work: work struct
  89  */
  90 static void ci_otg_work(struct work_struct *work)
  91 {
  92         struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
  93
  94         if (ci_otg_is_fsm_mode(ci) && !ci_otg_fsm_work(ci)) {
  95                 enable_irq(ci->irq);
  96                 return;
  97         }
  98
  99         if (ci->id_event) {
 100                 ci->id_event = false;
 101                 ci_handle_id_switch(ci);
 102         } else if (ci->b_sess_valid_event) {
 103                 ci->b_sess_valid_event = false;
 104                 ci_handle_vbus_change(ci);
 105         } else
 106                 dev_err(ci->dev, "unexpected event occurs at %s\n", __func__);
 107
 108         enable_irq(ci->irq);
 109 }
 110
 111
 112 /**
 113  * ci_hdrc_otg_init - initialize otg struct
 114  * ci: the controller
 115  */
 116 int ci_hdrc_otg_init(struct ci_hdrc *ci)
 117 {
 118         INIT_WORK(&ci->work, ci_otg_work);
 119         ci->wq = create_singlethread_workqueue("ci_otg");
 120         if (!ci->wq) {
 121                 dev_err(ci->dev, "can't create workqueue\n");
 122                 return -ENODEV;
 123         }
 124
 125         if (ci_otg_is_fsm_mode(ci))
 126                 return ci_hdrc_otg_fsm_init(ci);
 127
 128         return 0;
 129 }
 130
 131 /**
 132  * ci_hdrc_otg_destroy - destroy otg struct
 133  * ci: the controller
 134  */
 135 void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
 136 {
 137         if (ci->wq) {
 138                 flush_workqueue(ci->wq);
 139                 destroy_workqueue(ci->wq);
 140         }
 141         /* Disable all OTG irq and clear status */
 142         hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
 143                                                 OTGSC_INT_STATUS_BITS);
 144         if (ci_otg_is_fsm_mode(ci))
 145                 ci_hdrc_otg_fsm_remove(ci);
 146 }