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	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 */
41void 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 */
50enum 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
59void 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
71static 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 */
90static 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 */
116int 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 */
135void 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