/**
* exynos_drd_switch_set_host - bind/unbind the host controller driver.
*
* @otg: Pointer to the usb_otg structure.
* @host: Pointer to the usb_bus structure.
*
* Returns 0 on success otherwise negative errno.
*/
static int exynos_drd_switch_set_host(struct usb_otg *otg, struct usb_bus *host)
{
struct exynos_drd_switch *drd_switch = container_of(otg,
struct exynos_drd_switch, otg);
bool activate = false;
unsigned long flags;
spin_lock_irqsave(&drd_switch->lock, flags);
if (host) {
dev_dbg(otg->phy->dev, "Binding host %s\n", host->bus_name);
otg->host = host;
/*
* Prevents unnecessary activation of the work function.
* If both peripheral and host are set or if ID pin is low
* then we ensure that work function will enter to valid state.
*/
if (otg->gadget || drd_switch->id_state == A_DEV)
activate = true;
} else {
dev_dbg(otg->phy->dev, "Unbinding host\n");
if (otg->phy->state == OTG_STATE_A_HOST) {
exynos_drd_switch_start_host(otg, 0);
otg->host = NULL;
otg->phy->state = OTG_STATE_UNDEFINED;
activate = true;
} else {
otg->host = NULL;
}
}
spin_unlock_irqrestore(&drd_switch->lock, flags);
if (activate)
exynos_drd_switch_schedule_work(&drd_switch->work);
return 0;
}
/**
* exynos_drd_switch_work - work function.
*
* @w: Pointer to the exynos otg work structure.
*
* NOTE: After any change in phy->state,
* we must reschdule the state machine.
*/
static void exynos_drd_switch_work(struct work_struct *w)
{
struct exynos_drd_switch *drd_switch = container_of(w,
struct exynos_drd_switch, work.work);
struct usb_phy *phy = drd_switch->otg.phy;
struct delayed_work *work = &drd_switch->work;
enum usb_otg_state state, new_state;
enum id_pin_state id_state;
bool vbus_active;
unsigned long flags;
int ret = 0;
state = phy->state;
new_state = state;
if (atomic_read(&drd_switch->sm_reset)) {
if (state == OTG_STATE_A_HOST)
exynos_drd_switch_start_host(&drd_switch->otg, 0);
else if (state == OTG_STATE_B_PERIPHERAL)
exynos_drd_switch_start_peripheral(&drd_switch->otg, 0);
new_state = OTG_STATE_UNDEFINED;
goto exit;
}
spin_lock_irqsave(&drd_switch->lock, flags);
id_state = drd_switch->id_state;
vbus_active = drd_switch->vbus_active;
spin_unlock_irqrestore(&drd_switch->lock, flags);
/* Check OTG state */
switch (state) {
case OTG_STATE_UNDEFINED:
/* Switch to A or B-Device according to ID state */
if (id_state == B_DEV)
new_state = OTG_STATE_B_IDLE;
else if (id_state == A_DEV)
new_state = OTG_STATE_A_IDLE;
exynos_drd_switch_schedule_work(work);
break;
case OTG_STATE_B_IDLE:
if (id_state == A_DEV) {
new_state = OTG_STATE_A_IDLE;
exynos_drd_switch_schedule_work(work);
} else if (vbus_active) {
/* Start peripheral only if B-Session is valid */
ret = exynos_drd_switch_start_peripheral(
&drd_switch->otg, 1);
if (!ret) {
new_state = OTG_STATE_B_PERIPHERAL;
exynos_drd_switch_schedule_work(work);
} else if (ret == -EAGAIN) {
exynos_drd_switch_schedule_dwork(work,
EAGAIN_DELAY);
} else {
/* Fatal error */
dev_err(phy->dev,
"unable to start B-device\n");
}
} else {
dev_dbg(phy->dev, "VBus is not active\n");
}
break;
case OTG_STATE_B_PERIPHERAL:
dev_dbg(phy->dev, "OTG_STATE_B_PERIPHERAL\n");
if ((id_state == A_DEV) || !vbus_active) {
exynos_drd_switch_start_peripheral(&drd_switch->otg, 0);
new_state = OTG_STATE_B_IDLE;
exynos_drd_switch_schedule_work(work);
}
break;
case OTG_STATE_A_IDLE:
if (id_state == B_DEV) {
new_state = OTG_STATE_B_IDLE;
exynos_drd_switch_schedule_work(work);
} else {
/* Switch to A-Device */
ret = exynos_drd_switch_start_host(&drd_switch->otg, 1);
if (!ret || ret == -EINPROGRESS) {
new_state = OTG_STATE_A_HOST;
exynos_drd_switch_schedule_work(work);
} else if (ret == -EAGAIN || ret == -EBUSY) {
dev_vdbg(phy->dev, "host turn on retry\n");
exynos_drd_switch_schedule_dwork(work,
EAGAIN_DELAY);
} else {
/* Fatal error */
dev_err(phy->dev,
"unable to start A-device\n");
}
}
break;
case OTG_STATE_A_HOST:
dev_dbg(phy->dev, "OTG_STATE_A_HOST\n");
if (id_state == B_DEV) {
ret = exynos_drd_switch_start_host(&drd_switch->otg, 0);
/* Currently we ignore most of the errors */
if (ret == -EAGAIN) {
dev_vdbg(phy->dev, "host turn off retry\n");
exynos_drd_switch_schedule_dwork(work,
EAGAIN_DELAY);
} else {
if (ret == -EINVAL || ret == -EACCES)
/* Fatal error */
dev_err(phy->dev,
"unable to stop A-device\n");
new_state = OTG_STATE_A_IDLE;
exynos_drd_switch_schedule_work(work);
}
}
break;
default:
dev_err(phy->dev, "invalid otg-state\n");
}
exit:
WARN((phy->state != state), "PHY state has been changed outside of SM\n");
phy->state = new_state;
}
