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 */
31u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
32{
33	struct ci_hdrc_cable *cable;
34	u32 val = hw_read(ci, OP_OTGSC, mask);
35
36	/*
37	 * If using extcon framework for VBUS and/or ID signal
38	 * detection overwrite OTGSC register value
39	 */
40	cable = &ci->platdata->vbus_extcon;
41	if (!IS_ERR(cable->edev)) {
42		if (cable->changed)
43			val |= OTGSC_BSVIS;
44		else
45			val &= ~OTGSC_BSVIS;
46
47		cable->changed = false;
48
49		if (cable->state)
50			val |= OTGSC_BSV;
51		else
52			val &= ~OTGSC_BSV;
53	}
54
55	cable = &ci->platdata->id_extcon;
56	if (!IS_ERR(cable->edev)) {
57		if (cable->changed)
58			val |= OTGSC_IDIS;
59		else
60			val &= ~OTGSC_IDIS;
61
62		cable->changed = false;
63
64		if (cable->state)
65			val |= OTGSC_ID;
66		else
67			val &= ~OTGSC_ID;
68	}
69
70	return val;
71}
72
73/**
74 * hw_write_otgsc updates target bits of OTGSC register.
75 * @mask: bitfield mask
76 * @data: to be written
77 */
78void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
79{
80	hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
81}
82
83/**
84 * ci_otg_role - pick role based on ID pin state
85 * @ci: the controller
86 */
87enum ci_role ci_otg_role(struct ci_hdrc *ci)
88{
89	enum ci_role role = hw_read_otgsc(ci, OTGSC_ID)
90		? CI_ROLE_GADGET
91		: CI_ROLE_HOST;
92
93	return role;
94}
95
96void ci_handle_vbus_change(struct ci_hdrc *ci)
97{
98	if (!ci->is_otg)
99		return;
100
101	if (hw_read_otgsc(ci, OTGSC_BSV))
102		usb_gadget_vbus_connect(&ci->gadget);
103	else
104		usb_gadget_vbus_disconnect(&ci->gadget);
105}
106
107#define CI_VBUS_STABLE_TIMEOUT_MS 5000
108static void ci_handle_id_switch(struct ci_hdrc *ci)
109{
110	enum ci_role role = ci_otg_role(ci);
111
112	if (role != ci->role) {
113		dev_dbg(ci->dev, "switching from %s to %s\n",
114			ci_role(ci)->name, ci->roles[role]->name);
115
116		ci_role_stop(ci);
117
118		if (role == CI_ROLE_GADGET)
119			/* wait vbus lower than OTGSC_BSV */
120			hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0,
121					CI_VBUS_STABLE_TIMEOUT_MS);
122
123		ci_role_start(ci, role);
124	}
125}
126/**
127 * ci_otg_work - perform otg (vbus/id) event handle
128 * @work: work struct
129 */
130static void ci_otg_work(struct work_struct *work)
131{
132	struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
133
134	if (ci_otg_is_fsm_mode(ci) && !ci_otg_fsm_work(ci)) {
135		enable_irq(ci->irq);
136		return;
137	}
138
139	pm_runtime_get_sync(ci->dev);
140	if (ci->id_event) {
141		ci->id_event = false;
142		ci_handle_id_switch(ci);
143	} else if (ci->b_sess_valid_event) {
144		ci->b_sess_valid_event = false;
145		ci_handle_vbus_change(ci);
146	} else
147		dev_err(ci->dev, "unexpected event occurs at %s\n", __func__);
148	pm_runtime_put_sync(ci->dev);
149
150	enable_irq(ci->irq);
151}
152
153
154/**
155 * ci_hdrc_otg_init - initialize otg struct
156 * ci: the controller
157 */
158int ci_hdrc_otg_init(struct ci_hdrc *ci)
159{
160	INIT_WORK(&ci->work, ci_otg_work);
161	ci->wq = create_freezable_workqueue("ci_otg");
162	if (!ci->wq) {
163		dev_err(ci->dev, "can't create workqueue\n");
164		return -ENODEV;
165	}
166
167	if (ci_otg_is_fsm_mode(ci))
168		return ci_hdrc_otg_fsm_init(ci);
169
170	return 0;
171}
172
173/**
174 * ci_hdrc_otg_destroy - destroy otg struct
175 * ci: the controller
176 */
177void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
178{
179	if (ci->wq) {
180		flush_workqueue(ci->wq);
181		destroy_workqueue(ci->wq);
182	}
183	/* Disable all OTG irq and clear status */
184	hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
185						OTGSC_INT_STATUS_BITS);
186	if (ci_otg_is_fsm_mode(ci))
187		ci_hdrc_otg_fsm_remove(ci);
188}
189