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 } 147