// SPDX-License-Identifier: GPL-2.0 /* * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices * * Copyright (c) 2008 Philipp Zabel */ #include #include #include #include #include #include #include #include #include #include #include /* * 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 = gpio_vbus_remove, }; module_platform_driver(gpio_vbus_driver); MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver"); MODULE_AUTHOR("Philipp Zabel"); MODULE_LICENSE("GPL");