1 files changed, 384 insertions, 0 deletions

diff --git a/drivers/usb/phy/phy-gpio-vbus-usb.c b/drivers/usb/phy/phy-gpio-vbus-usb.c
new file mode 100644
index 000000000..f13f55307
--- /dev/null
+++ b/drivers/usb/phy/phy-gpio-vbus-usb.c
@@ -0,0 +1,384 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
+ *
+ * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
+ */
+
+#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 int 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);
+
+	return 0;
+}
+
+#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");
+
+static struct platform_driver gpio_vbus_driver = {
+	.driver = {
+		.name  = "gpio-vbus",
+#ifdef CONFIG_PM
+		.pm = &gpio_vbus_dev_pm_ops,
+#endif
+	},
+	.probe		= gpio_vbus_probe,
+	.remove		= gpio_vbus_remove,
+};
+
+module_platform_driver(gpio_vbus_driver);
+
+MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
+MODULE_AUTHOR("Philipp Zabel");
+MODULE_LICENSE("GPL");