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 */
 30enum 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
 40void 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
 56static 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 */
 75static 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 */
 96int 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 */
112void 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}