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 */
29u32 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 */
83void 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 */
122enum 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
131void 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 */
151static 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
168void 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 */
209static 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 */
240int 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 */
259void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
260{
261	if (ci->wq)
262		destroy_workqueue(ci->wq);
263
264	/* Disable all OTG irq and clear status */
265	hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
266						OTGSC_INT_STATUS_BITS);
267	if (ci_otg_is_fsm_mode(ci))
268		ci_hdrc_otg_fsm_remove(ci);
269}
270