// SPDX-License-Identifier: GPL-2.0
/*
* gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
*
* Copyright (c) 2008 Philipp Zabel <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/usb.h>
#include <linux/workqueue.h>
#include <linux/regulator/consumer.h>
#include <linux/usb/gadget.h>
#include <linux/usb/otg.h>
/*
* A simple GPIO VBUS sensing driver for B peripheral only devices
* with internal transceivers. It can control a D+ pullup GPIO and
* a regulator to limit the current drawn from VBUS.
*
* Needs to be loaded before the UDC driver that will use it.
*/
struct gpio_vbus_data {
struct gpio_desc *vbus_gpiod;
struct gpio_desc *pullup_gpiod;
struct usb_phy phy;
struct device *dev;
struct regulator *vbus_draw;
int vbus_draw_enabled;
unsigned mA;
struct delayed_work work;
int vbus;
int irq;
};
/*
* This driver relies on "both edges" triggering. VBUS has 100 msec to
* stabilize, so the peripheral controller driver may need to cope with
* some bouncing due to current surges (e.g. charging local capacitance)
* and contact chatter.
*
* REVISIT in desperate straits, toggling between rising and falling
* edges might be workable.
*/
#define VBUS_IRQ_FLAGS \
(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
/* interface to regulator framework */
static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
{
struct regulator *vbus_draw = gpio_vbus->vbus_draw;
int enabled;
int ret;
if (!vbus_draw)
return;
enabled = gpio_vbus->vbus_draw_enabled;
if (mA) {
regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
if (!enabled) {
ret = regulator_enable(vbus_draw);
if (ret < 0)
return;
gpio_vbus->vbus_draw_enabled = 1;
}
} else {
if (enabled) {
ret = regulator_disable(vbus_draw);
if (ret < 0)
return;
gpio_vbus->vbus_draw_enabled = 0;
}
}
gpio_vbus->mA = mA;
}
static int is_vbus_powered(struct gpio_vbus_data *gpio_vbus)
{
return gpiod_get_value(gpio_vbus->vbus_gpiod);
}
static void gpio_vbus_work(struct work_struct *work)
{
struct gpio_vbus_data *gpio_vbus =
container_of(work, struct gpio_vbus_data, work.work);
int status, vbus;
if (!gpio_vbus->phy.otg->gadget)
return;
vbus = is_vbus_powered(gpio_vbus);
if ((vbus ^ gpio_vbus->vbus) == 0)
return;
gpio_vbus->vbus = vbus;
/* Peripheral controllers which manage the pullup themselves won't have
* a pullup GPIO configured here. If it's configured here, we'll do
* what isp1301_omap::b_peripheral() does and enable the pullup here...
* although that may complicate usb_gadget_{,dis}connect() support.
*/
if (vbus) {
status = USB_EVENT_VBUS;
gpio_vbus->phy.otg->state = OTG_STATE_B_PERIPHERAL;
gpio_vbus->phy.last_event = status;
usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
/* drawing a "unit load" is *always* OK, except for OTG */
set_vbus_draw(gpio_vbus, 100);
/* optionally enable D+ pullup */
if (gpio_vbus->pullup_gpiod)
gpiod_set_value(gpio_vbus->pullup_gpiod, 1);
atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
status, gpio_vbus->phy.otg->gadget);
usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_ENUMERATED);
} else {
/* optionally disable D+ pullup */
if (gpio_vbus->pullup_gpiod)
gpiod_set_value(gpio_vbus->pullup_gpiod, 0);
set_vbus_draw(gpio_vbus, 0);
usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
status = USB_EVENT_NONE;
gpio_vbus->phy.otg->state = OTG_STATE_B_IDLE;
gpio_vbus->phy.last_event = status;
atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
status, gpio_vbus->phy.otg->gadget);
usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_NONE);
}
}
/* VBUS change IRQ handler */
static irqreturn_t gpio_vbus_irq(int irq, void *data)
{
struct platform_device *pdev = data;
struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
struct usb_otg *otg = gpio_vbus->phy.otg;
dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
is_vbus_powered(gpio_vbus) ? "supplied" : "inactive",
otg->gadget ? otg->gadget->name : "none");
if (otg->gadget)
schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
return IRQ_HANDLED;
}
/* OTG transceiver interface */
/* bind/unbind the peripheral controller */
static int gpio_vbus_set_peripheral(struct usb_otg *otg,
struct usb_gadget *gadget)
{
struct gpio_vbus_data *gpio_vbus;
struct platform_device *pdev;
gpio_vbus = container_of(otg->usb_phy, struct gpio_vbus_data, phy);
pdev = to_platform_device(gpio_vbus->dev);
if (!gadget) {
dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
otg->gadget->name);
/* optionally disable D+ pullup */
if (gpio_vbus->pullup_gpiod)
gpiod_set_value(gpio_vbus->pullup_gpiod, 0);
set_vbus_draw(gpio_vbus, 0);
usb_gadget_vbus_disconnect(otg->gadget);
otg->state = OTG_STATE_UNDEFINED;
otg->gadget = NULL;
return 0;
}
otg->gadget = gadget;
dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
/* initialize connection state */
gpio_vbus->vbus = 0; /* start with disconnected */
gpio_vbus_irq(gpio_vbus->irq, pdev);
return 0;
}
/* effective for B devices, ignored for A-peripheral */
static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
{
struct gpio_vbus_data *gpio_vbus;
gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
if (phy->otg->state == OTG_STATE_B_PERIPHERAL)
set_vbus_draw(gpio_vbus, mA);
return 0;
}
/* for non-OTG B devices: set/clear transceiver suspend mode */
static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
{
struct gpio_vbus_data *gpio_vbus;
gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
/* draw max 0 mA from vbus in suspend mode; or the previously
* recorded amount of current if not suspended
*
* NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
* if they're wake-enabled ... we don't handle that yet.
*/
return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
}
/* platform driver interface */
static int gpio_vbus_probe(struct platform_device *pdev)
{
struct gpio_vbus_data *gpio_vbus;
struct resource *res;
struct device *dev = &pdev->dev;
int err, irq;
unsigned long irqflags;
gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
GFP_KERNEL);
if (!gpio_vbus)
return -ENOMEM;
gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
GFP_KERNEL);
if (!gpio_vbus->phy.otg)
return -ENOMEM;
platform_set_drvdata(pdev, gpio_vbus);
gpio_vbus->dev = &pdev->dev;
gpio_vbus->phy.label = "gpio-vbus";
gpio_vbus->phy.dev = gpio_vbus->dev;
gpio_vbus->phy.set_power = gpio_vbus_set_power;
gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
gpio_vbus->phy.otg->state = OTG_STATE_UNDEFINED;
gpio_vbus->phy.otg->usb_phy = &gpio_vbus->phy;
gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
/* Look up the VBUS sensing GPIO */
gpio_vbus->vbus_gpiod = devm_gpiod_get(dev, "vbus", GPIOD_IN);
if (IS_ERR(gpio_vbus->vbus_gpiod)) {
err = PTR_ERR(gpio_vbus->vbus_gpiod);
dev_err(&pdev->dev, "can't request vbus gpio, err: %d\n", err);
return err;
}
gpiod_set_consumer_name(gpio_vbus->vbus_gpiod, "vbus_detect");
res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (res) {
irq = res->start;
irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
} else {
irq = gpiod_to_irq(gpio_vbus->vbus_gpiod);
irqflags = VBUS_IRQ_FLAGS;
}
gpio_vbus->irq = irq;
/*
* The VBUS sensing GPIO should have a pulldown, which will normally be
* part of a resistor ladder turning a 4.0V-5.25V level on VBUS into a
* value the GPIO detects as active. Some systems will use comparators.
* Get the optional D+ or D- pullup GPIO. If the data line pullup is
* in use, initialize it to "not pulling up"
*/
gpio_vbus->pullup_gpiod = devm_gpiod_get_optional(dev, "pullup",
GPIOD_OUT_LOW);
if (IS_ERR(gpio_vbus->pullup_gpiod)) {
err = PTR_ERR(gpio_vbus->pullup_gpiod);
dev_err(&pdev->dev, "can't request pullup gpio, err: %d\n",
err);
return err;
}
if (gpio_vbus->pullup_gpiod)
gpiod_set_consumer_name(gpio_vbus->pullup_gpiod, "udc_pullup");
err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
"vbus_detect", pdev);
if (err) {
dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
irq, err);
return err;
}
INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
gpio_vbus->vbus_draw = devm_regulator_get(&pdev->dev, "vbus_draw");
if (IS_ERR(gpio_vbus->vbus_draw)) {
dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
PTR_ERR(gpio_vbus->vbus_draw));
gpio_vbus->vbus_draw = NULL;
}
/* only active when a gadget is registered */
err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
if (err) {
dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
err);
return err;
}
/* TODO: wakeup could be enabled here with device_init_wakeup(dev, 1) */
return 0;
}
static void gpio_vbus_remove(struct platform_device *pdev)
{
struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
device_init_wakeup(&pdev->dev, 0);
cancel_delayed_work_sync(&gpio_vbus->work);
usb_remove_phy(&gpio_vbus->phy);
}
#ifdef CONFIG_PM
static int gpio_vbus_pm_suspend(struct device *dev)
{
struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(gpio_vbus->irq);
return 0;
}
static int gpio_vbus_pm_resume(struct device *dev)
{
struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(gpio_vbus->irq);
return 0;
}
static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
.suspend = gpio_vbus_pm_suspend,
.resume = gpio_vbus_pm_resume,
};
#endif
MODULE_ALIAS("platform:gpio-vbus");
/*
* NOTE: this driver matches against "gpio-usb-b-connector" for
* devices that do NOT support role switch.
*/
static const struct of_device_id gpio_vbus_of_match[] = {
{
.compatible = "gpio-usb-b-connector",
},
{},
};
MODULE_DEVICE_TABLE(of, gpio_vbus_of_match);
static struct platform_driver gpio_vbus_driver = {
.driver = {
.name = "gpio-vbus",
#ifdef CONFIG_PM
.pm = &gpio_vbus_dev_pm_ops,
#endif
.of_match_table = gpio_vbus_of_match,
},
.probe = gpio_vbus_probe,
.remove_new = gpio_vbus_remove,
};
module_platform_driver(gpio_vbus_driver);
MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
MODULE_AUTHOR("Philipp Zabel");
MODULE_LICENSE("GPL");
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