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, it may include OTG operation 15 * in the future. 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 26 /** 27 * ci_otg_role - pick role based on ID pin state 28 * @ci: the controller 29 */ 30 enum ci_role ci_otg_role(struct ci_hdrc *ci) 31 { 32 u32 sts = hw_read(ci, OP_OTGSC, ~0); 33 enum ci_role role = sts & OTGSC_ID 34 ? CI_ROLE_GADGET 35 : CI_ROLE_HOST; 36 37 return role; 38 } 39 40 void ci_handle_vbus_change(struct ci_hdrc *ci) 41 { 42 u32 otgsc; 43 44 if (!ci->is_otg) 45 return; 46 47 otgsc = hw_read(ci, OP_OTGSC, ~0); 48 49 if (otgsc & OTGSC_BSV) 50 usb_gadget_vbus_connect(&ci->gadget); 51 else 52 usb_gadget_vbus_disconnect(&ci->gadget); 53 } 54 55 #define CI_VBUS_STABLE_TIMEOUT_MS 5000 56 static void ci_handle_id_switch(struct ci_hdrc *ci) 57 { 58 enum ci_role role = ci_otg_role(ci); 59 60 if (role != ci->role) { 61 dev_dbg(ci->dev, "switching from %s to %s\n", 62 ci_role(ci)->name, ci->roles[role]->name); 63 64 ci_role_stop(ci); 65 /* wait vbus lower than OTGSC_BSV */ 66 hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0, 67 CI_VBUS_STABLE_TIMEOUT_MS); 68 ci_role_start(ci, role); 69 } 70 } 71 /** 72 * ci_otg_work - perform otg (vbus/id) event handle 73 * @work: work struct 74 */ 75 static void ci_otg_work(struct work_struct *work) 76 { 77 struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work); 78 79 if (ci->id_event) { 80 ci->id_event = false; 81 ci_handle_id_switch(ci); 82 } else if (ci->b_sess_valid_event) { 83 ci->b_sess_valid_event = false; 84 ci_handle_vbus_change(ci); 85 } else 86 dev_err(ci->dev, "unexpected event occurs at %s\n", __func__); 87 88 enable_irq(ci->irq); 89 } 90 91 92 /** 93 * ci_hdrc_otg_init - initialize otg struct 94 * ci: the controller 95 */ 96 int ci_hdrc_otg_init(struct ci_hdrc *ci) 97 { 98 INIT_WORK(&ci->work, ci_otg_work); 99 ci->wq = create_singlethread_workqueue("ci_otg"); 100 if (!ci->wq) { 101 dev_err(ci->dev, "can't create workqueue\n"); 102 return -ENODEV; 103 } 104 105 return 0; 106 } 107 108 /** 109 * ci_hdrc_otg_destroy - destroy otg struct 110 * ci: the controller 111 */ 112 void ci_hdrc_otg_destroy(struct ci_hdrc *ci) 113 { 114 if (ci->wq) { 115 flush_workqueue(ci->wq); 116 destroy_workqueue(ci->wq); 117 } 118 ci_disable_otg_interrupt(ci, OTGSC_INT_EN_BITS); 119 ci_clear_otg_interrupt(ci, OTGSC_INT_STATUS_BITS); 120 } 121