1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * otg.c - ChipIdea USB IP core OTG driver
4 *
5 * Copyright (C) 2013 Freescale Semiconductor, Inc.
6 *
7 * Author: Peter Chen
8 */
9
10 /*
11 * This file mainly handles otgsc register, OTG fsm operations for HNP and SRP
12 * are also included.
13 */
14
15 #include <linux/usb/otg.h>
16 #include <linux/usb/gadget.h>
17 #include <linux/usb/chipidea.h>
18
19 #include "ci.h"
20 #include "bits.h"
21 #include "otg.h"
22 #include "otg_fsm.h"
23
24 /**
25 * hw_read_otgsc - returns otgsc register bits value.
26 * @ci: the controller
27 * @mask: bitfield mask
28 */
hw_read_otgsc(struct ci_hdrc * ci,u32 mask)29 u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
30 {
31 struct ci_hdrc_cable *cable;
32 u32 val = hw_read(ci, OP_OTGSC, mask);
33
34 /*
35 * If using extcon framework for VBUS and/or ID signal
36 * detection overwrite OTGSC register value
37 */
38 cable = &ci->platdata->vbus_extcon;
39 if (!IS_ERR(cable->edev) || ci->role_switch) {
40 if (cable->changed)
41 val |= OTGSC_BSVIS;
42 else
43 val &= ~OTGSC_BSVIS;
44
45 if (cable->connected)
46 val |= OTGSC_BSV;
47 else
48 val &= ~OTGSC_BSV;
49
50 if (cable->enabled)
51 val |= OTGSC_BSVIE;
52 else
53 val &= ~OTGSC_BSVIE;
54 }
55
56 cable = &ci->platdata->id_extcon;
57 if (!IS_ERR(cable->edev) || ci->role_switch) {
58 if (cable->changed)
59 val |= OTGSC_IDIS;
60 else
61 val &= ~OTGSC_IDIS;
62
63 if (cable->connected)
64 val &= ~OTGSC_ID; /* host */
65 else
66 val |= OTGSC_ID; /* device */
67
68 if (cable->enabled)
69 val |= OTGSC_IDIE;
70 else
71 val &= ~OTGSC_IDIE;
72 }
73
74 return val & mask;
75 }
76
77 /**
78 * hw_write_otgsc - updates target bits of OTGSC register.
79 * @ci: the controller
80 * @mask: bitfield mask
81 * @data: to be written
82 */
hw_write_otgsc(struct ci_hdrc * ci,u32 mask,u32 data)83 void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
84 {
85 struct ci_hdrc_cable *cable;
86
87 cable = &ci->platdata->vbus_extcon;
88 if (!IS_ERR(cable->edev) || ci->role_switch) {
89 if (data & mask & OTGSC_BSVIS)
90 cable->changed = false;
91
92 /* Don't enable vbus interrupt if using external notifier */
93 if (data & mask & OTGSC_BSVIE) {
94 cable->enabled = true;
95 data &= ~OTGSC_BSVIE;
96 } else if (mask & OTGSC_BSVIE) {
97 cable->enabled = false;
98 }
99 }
100
101 cable = &ci->platdata->id_extcon;
102 if (!IS_ERR(cable->edev) || ci->role_switch) {
103 if (data & mask & OTGSC_IDIS)
104 cable->changed = false;
105
106 /* Don't enable id interrupt if using external notifier */
107 if (data & mask & OTGSC_IDIE) {
108 cable->enabled = true;
109 data &= ~OTGSC_IDIE;
110 } else if (mask & OTGSC_IDIE) {
111 cable->enabled = false;
112 }
113 }
114
115 hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
116 }
117
118 /**
119 * ci_otg_role - pick role based on ID pin state
120 * @ci: the controller
121 */
ci_otg_role(struct ci_hdrc * ci)122 enum ci_role ci_otg_role(struct ci_hdrc *ci)
123 {
124 enum ci_role role = hw_read_otgsc(ci, OTGSC_ID)
125 ? CI_ROLE_GADGET
126 : CI_ROLE_HOST;
127
128 return role;
129 }
130
ci_handle_vbus_change(struct ci_hdrc * ci)131 void ci_handle_vbus_change(struct ci_hdrc *ci)
132 {
133 if (!ci->is_otg)
134 return;
135
136 if (hw_read_otgsc(ci, OTGSC_BSV) && !ci->vbus_active)
137 usb_gadget_vbus_connect(&ci->gadget);
138 else if (!hw_read_otgsc(ci, OTGSC_BSV) && ci->vbus_active)
139 usb_gadget_vbus_disconnect(&ci->gadget);
140 }
141
142 /**
143 * hw_wait_vbus_lower_bsv - When we switch to device mode, the vbus value
144 * should be lower than OTGSC_BSV before connecting
145 * to host.
146 *
147 * @ci: the controller
148 *
149 * This function returns an error code if timeout
150 */
hw_wait_vbus_lower_bsv(struct ci_hdrc * ci)151 static int hw_wait_vbus_lower_bsv(struct ci_hdrc *ci)
152 {
153 unsigned long elapse = jiffies + msecs_to_jiffies(5000);
154 u32 mask = OTGSC_BSV;
155
156 while (hw_read_otgsc(ci, mask)) {
157 if (time_after(jiffies, elapse)) {
158 dev_err(ci->dev, "timeout waiting for %08x in OTGSC\n",
159 mask);
160 return -ETIMEDOUT;
161 }
162 msleep(20);
163 }
164
165 return 0;
166 }
167
ci_handle_id_switch(struct ci_hdrc * ci)168 static void ci_handle_id_switch(struct ci_hdrc *ci)
169 {
170 enum ci_role role;
171
172 mutex_lock(&ci->mutex);
173 role = ci_otg_role(ci);
174 if (role != ci->role) {
175 dev_dbg(ci->dev, "switching from %s to %s\n",
176 ci_role(ci)->name, ci->roles[role]->name);
177
178 if (ci->vbus_active && ci->role == CI_ROLE_GADGET)
179 /*
180 * vbus disconnect event is lost due to role
181 * switch occurs during system suspend.
182 */
183 usb_gadget_vbus_disconnect(&ci->gadget);
184
185 ci_role_stop(ci);
186
187 if (role == CI_ROLE_GADGET &&
188 IS_ERR(ci->platdata->vbus_extcon.edev))
189 /*
190 * Wait vbus lower than OTGSC_BSV before connecting
191 * to host. If connecting status is from an external
192 * connector instead of register, we don't need to
193 * care vbus on the board, since it will not affect
194 * external connector status.
195 */
196 hw_wait_vbus_lower_bsv(ci);
197
198 ci_role_start(ci, role);
199 /* vbus change may have already occurred */
200 if (role == CI_ROLE_GADGET)
201 ci_handle_vbus_change(ci);
202 }
203 mutex_unlock(&ci->mutex);
204 }
205 /**
206 * ci_otg_work - perform otg (vbus/id) event handle
207 * @work: work struct
208 */
ci_otg_work(struct work_struct * work)209 static void ci_otg_work(struct work_struct *work)
210 {
211 struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
212
213 if (ci_otg_is_fsm_mode(ci) && !ci_otg_fsm_work(ci)) {
214 enable_irq(ci->irq);
215 return;
216 }
217
218 pm_runtime_get_sync(ci->dev);
219
220 if (ci->id_event) {
221 ci->id_event = false;
222 ci_handle_id_switch(ci);
223 }
224
225 if (ci->b_sess_valid_event) {
226 ci->b_sess_valid_event = false;
227 ci_handle_vbus_change(ci);
228 }
229
230 pm_runtime_put_sync(ci->dev);
231
232 enable_irq(ci->irq);
233 }
234
235
236 /**
237 * ci_hdrc_otg_init - initialize otg struct
238 * @ci: the controller
239 */
ci_hdrc_otg_init(struct ci_hdrc * ci)240 int ci_hdrc_otg_init(struct ci_hdrc *ci)
241 {
242 INIT_WORK(&ci->work, ci_otg_work);
243 ci->wq = create_freezable_workqueue("ci_otg");
244 if (!ci->wq) {
245 dev_err(ci->dev, "can't create workqueue\n");
246 return -ENODEV;
247 }
248
249 if (ci_otg_is_fsm_mode(ci))
250 return ci_hdrc_otg_fsm_init(ci);
251
252 return 0;
253 }
254
255 /**
256 * ci_hdrc_otg_destroy - destroy otg struct
257 * @ci: the controller
258 */
ci_hdrc_otg_destroy(struct ci_hdrc * ci)259 void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
260 {
261 if (ci->wq) {
262 flush_workqueue(ci->wq);
263 destroy_workqueue(ci->wq);
264 }
265 /* Disable all OTG irq and clear status */
266 hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
267 OTGSC_INT_STATUS_BITS);
268 if (ci_otg_is_fsm_mode(ci))
269 ci_hdrc_otg_fsm_remove(ci);
270 }
271