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/*
* otg.c - ChipIdea USB IP core OTG driver
*
* Copyright (C) 2013 Freescale Semiconductor, Inc.
*
* Author: Peter Chen
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*
* This file mainly handles otgsc register, OTG fsm operations for HNP and SRP
* are also included.
*/
#include <linux/usb/otg.h>
#include <linux/usb/gadget.h>
#include <linux/usb/chipidea.h>
#include "ci.h"
#include "bits.h"
#include "otg.h"
#include "otg_fsm.h"
/**
* hw_read_otgsc returns otgsc register bits value.
* @mask: bitfield mask
*/
u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
{
struct ci_hdrc_cable *cable;
u32 val = hw_read(ci, OP_OTGSC, mask);
/*
* If using extcon framework for VBUS and/or ID signal
* detection overwrite OTGSC register value
*/
cable = &ci->platdata->vbus_extcon;
if (!IS_ERR(cable->edev)) {
if (cable->changed)
val |= OTGSC_BSVIS;
else
val &= ~OTGSC_BSVIS;
if (cable->state)
val |= OTGSC_BSV;
else
val &= ~OTGSC_BSV;
if (cable->enabled)
val |= OTGSC_BSVIE;
else
val &= ~OTGSC_BSVIE;
}
cable = &ci->platdata->id_extcon;
if (!IS_ERR(cable->edev)) {
if (cable->changed)
val |= OTGSC_IDIS;
else
val &= ~OTGSC_IDIS;
if (cable->state)
val |= OTGSC_ID;
else
val &= ~OTGSC_ID;
if (cable->enabled)
val |= OTGSC_IDIE;
else
val &= ~OTGSC_IDIE;
}
return val & mask;
}
/**
* hw_write_otgsc updates target bits of OTGSC register.
* @mask: bitfield mask
* @data: to be written
*/
void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
{
struct ci_hdrc_cable *cable;
cable = &ci->platdata->vbus_extcon;
if (!IS_ERR(cable->edev)) {
if (data & mask & OTGSC_BSVIS)
cable->changed = false;
/* Don't enable vbus interrupt if using external notifier */
if (data & mask & OTGSC_BSVIE) {
cable->enabled = true;
data &= ~OTGSC_BSVIE;
} else if (mask & OTGSC_BSVIE) {
cable->enabled = false;
}
}
cable = &ci->platdata->id_extcon;
if (!IS_ERR(cable->edev)) {
if (data & mask & OTGSC_IDIS)
cable->changed = false;
/* Don't enable id interrupt if using external notifier */
if (data & mask & OTGSC_IDIE) {
cable->enabled = true;
data &= ~OTGSC_IDIE;
} else if (mask & OTGSC_IDIE) {
cable->enabled = false;
}
}
hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
}
/**
* ci_otg_role - pick role based on ID pin state
* @ci: the controller
*/
enum ci_role ci_otg_role(struct ci_hdrc *ci)
{
enum ci_role role = hw_read_otgsc(ci, OTGSC_ID)
? CI_ROLE_GADGET
: CI_ROLE_HOST;
return role;
}
void ci_handle_vbus_change(struct ci_hdrc *ci)
{
if (!ci->is_otg)
return;
if (hw_read_otgsc(ci, OTGSC_BSV))
usb_gadget_vbus_connect(&ci->gadget);
else
usb_gadget_vbus_disconnect(&ci->gadget);
}
/**
* When we switch to device mode, the vbus value should be lower
* than OTGSC_BSV before connecting to host.
*
* @ci: the controller
*
* This function returns an error code if timeout
*/
static int hw_wait_vbus_lower_bsv(struct ci_hdrc *ci)
{
unsigned long elapse = jiffies + msecs_to_jiffies(5000);
u32 mask = OTGSC_BSV;
while (hw_read_otgsc(ci, mask)) {
if (time_after(jiffies, elapse)) {
dev_err(ci->dev, "timeout waiting for %08x in OTGSC\n",
mask);
return -ETIMEDOUT;
}
msleep(20);
}
return 0;
}
static void ci_handle_id_switch(struct ci_hdrc *ci)
{
enum ci_role role = ci_otg_role(ci);
if (role != ci->role) {
dev_dbg(ci->dev, "switching from %s to %s\n",
ci_role(ci)->name, ci->roles[role]->name);
ci_role_stop(ci);
if (role == CI_ROLE_GADGET)
/*
* wait vbus lower than OTGSC_BSV before connecting
* to host
*/
hw_wait_vbus_lower_bsv(ci);
ci_role_start(ci, role);
}
}
/**
* ci_otg_work - perform otg (vbus/id) event handle
* @work: work struct
*/
static void ci_otg_work(struct work_struct *work)
{
struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
if (ci_otg_is_fsm_mode(ci) && !ci_otg_fsm_work(ci)) {
enable_irq(ci->irq);
return;
}
pm_runtime_get_sync(ci->dev);
if (ci->id_event) {
ci->id_event = false;
ci_handle_id_switch(ci);
} else if (ci->b_sess_valid_event) {
ci->b_sess_valid_event = false;
ci_handle_vbus_change(ci);
} else
dev_err(ci->dev, "unexpected event occurs at %s\n", __func__);
pm_runtime_put_sync(ci->dev);
enable_irq(ci->irq);
}
/**
* ci_hdrc_otg_init - initialize otg struct
* ci: the controller
*/
int ci_hdrc_otg_init(struct ci_hdrc *ci)
{
INIT_WORK(&ci->work, ci_otg_work);
ci->wq = create_freezable_workqueue("ci_otg");
if (!ci->wq) {
dev_err(ci->dev, "can't create workqueue\n");
return -ENODEV;
}
if (ci_otg_is_fsm_mode(ci))
return ci_hdrc_otg_fsm_init(ci);
return 0;
}
/**
* ci_hdrc_otg_destroy - destroy otg struct
* ci: the controller
*/
void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
{
if (ci->wq) {
flush_workqueue(ci->wq);
destroy_workqueue(ci->wq);
}
/* Disable all OTG irq and clear status */
hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
OTGSC_INT_STATUS_BITS);
if (ci_otg_is_fsm_mode(ci))
ci_hdrc_otg_fsm_remove(ci);
}
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