/* * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices * * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com> * * 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. */ #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/gpio.h> #include <linux/interrupt.h> #include <linux/usb.h> #include <linux/regulator/consumer.h> #include <linux/usb/gadget.h> #include <linux/usb/gpio_vbus.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 otg_transceiver otg; struct device *dev; struct regulator *vbus_draw; int vbus_draw_enabled; unsigned mA; }; /* * 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_SAMPLE_RANDOM | 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; if (!vbus_draw) return; enabled = gpio_vbus->vbus_draw_enabled; if (mA) { regulator_set_current_limit(vbus_draw, 0, 1000 * mA); if (!enabled) { regulator_enable(vbus_draw); gpio_vbus->vbus_draw_enabled = 1; } } else { if (enabled) { regulator_disable(vbus_draw); gpio_vbus->vbus_draw_enabled = 0; } } gpio_vbus->mA = mA; } /* VBUS change IRQ handler */ static irqreturn_t gpio_vbus_irq(int irq, void *data) { struct platform_device *pdev = data; struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data; struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev); int gpio, vbus; vbus = gpio_get_value(pdata->gpio_vbus); if (pdata->gpio_vbus_inverted) vbus = !vbus; dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n", vbus ? "supplied" : "inactive", gpio_vbus->otg.gadget ? gpio_vbus->otg.gadget->name : "none"); if (!gpio_vbus->otg.gadget) return IRQ_HANDLED; /* Peripheral controllers which manage the pullup themselves won't have * gpio_pullup 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. */ gpio = pdata->gpio_pullup; if (vbus) { gpio_vbus->otg.state = OTG_STATE_B_PERIPHERAL; usb_gadget_vbus_connect(gpio_vbus->otg.gadget); /* drawing a "unit load" is *always* OK, except for OTG */ set_vbus_draw(gpio_vbus, 100); /* optionally enable D+ pullup */ if (gpio_is_valid(gpio)) gpio_set_value(gpio, !pdata->gpio_pullup_inverted); } else { /* optionally disable D+ pullup */ if (gpio_is_valid(gpio)) gpio_set_value(gpio, pdata->gpio_pullup_inverted); set_vbus_draw(gpio_vbus, 0); usb_gadget_vbus_disconnect(gpio_vbus->otg.gadget); gpio_vbus->otg.state = OTG_STATE_B_IDLE; } return IRQ_HANDLED; } /* OTG transceiver interface */ /* bind/unbind the peripheral controller */ static int gpio_vbus_set_peripheral(struct otg_transceiver *otg, struct usb_gadget *gadget) { struct gpio_vbus_data *gpio_vbus; struct gpio_vbus_mach_info *pdata; struct platform_device *pdev; int gpio, irq; gpio_vbus = container_of(otg, struct gpio_vbus_data, otg); pdev = to_platform_device(gpio_vbus->dev); pdata = gpio_vbus->dev->platform_data; irq = gpio_to_irq(pdata->gpio_vbus); gpio = pdata->gpio_pullup; if (!gadget) { dev_dbg(&pdev->dev, "unregistering gadget '%s'\n", otg->gadget->name); /* optionally disable D+ pullup */ if (gpio_is_valid(gpio)) gpio_set_value(gpio, pdata->gpio_pullup_inverted); 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_irq(irq, pdev); return 0; } /* effective for B devices, ignored for A-peripheral */ static int gpio_vbus_set_power(struct otg_transceiver *otg, unsigned mA) { struct gpio_vbus_data *gpio_vbus; gpio_vbus = container_of(otg, struct gpio_vbus_data, otg); if (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 otg_transceiver *otg, int suspend) { struct gpio_vbus_data *gpio_vbus; gpio_vbus = container_of(otg, struct gpio_vbus_data, otg); /* 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(otg, suspend ? 0 : gpio_vbus->mA); } /* platform driver interface */ static int __init gpio_vbus_probe(struct platform_device *pdev) { struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data; struct gpio_vbus_data *gpio_vbus; struct resource *res; int err, gpio, irq; if (!pdata || !gpio_is_valid(pdata->gpio_vbus)) return -EINVAL; gpio = pdata->gpio_vbus; gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL); if (!gpio_vbus) return -ENOMEM; platform_set_drvdata(pdev, gpio_vbus); gpio_vbus->dev = &pdev->dev; gpio_vbus->otg.label = "gpio-vbus"; gpio_vbus->otg.state = OTG_STATE_UNDEFINED; gpio_vbus->otg.set_peripheral = gpio_vbus_set_peripheral; gpio_vbus->otg.set_power = gpio_vbus_set_power; gpio_vbus->otg.set_suspend = gpio_vbus_set_suspend; err = gpio_request(gpio, "vbus_detect"); if (err) { dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n", gpio, err); goto err_gpio; } gpio_direction_input(gpio); res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (res) { irq = res->start; res->flags &= IRQF_TRIGGER_MASK; res->flags |= IRQF_SAMPLE_RANDOM | IRQF_SHARED; } else irq = gpio_to_irq(gpio); /* if data line pullup is in use, initialize it to "not pulling up" */ gpio = pdata->gpio_pullup; if (gpio_is_valid(gpio)) { err = gpio_request(gpio, "udc_pullup"); if (err) { dev_err(&pdev->dev, "can't request pullup gpio %d, err: %d\n", gpio, err); gpio_free(pdata->gpio_vbus); goto err_gpio; } gpio_direction_output(gpio, pdata->gpio_pullup_inverted); } err = request_irq(irq, gpio_vbus_irq, VBUS_IRQ_FLAGS, "vbus_detect", pdev); if (err) { dev_err(&pdev->dev, "can't request irq %i, err: %d\n", irq, err); goto err_irq; } /* only active when a gadget is registered */ err = otg_set_transceiver(&gpio_vbus->otg); if (err) { dev_err(&pdev->dev, "can't register transceiver, err: %d\n", err); goto err_otg; } gpio_vbus->vbus_draw = 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; } return 0; err_otg: free_irq(irq, &pdev->dev); err_irq: if (gpio_is_valid(pdata->gpio_pullup)) gpio_free(pdata->gpio_pullup); gpio_free(pdata->gpio_vbus); err_gpio: platform_set_drvdata(pdev, NULL); kfree(gpio_vbus); return err; } static int __exit gpio_vbus_remove(struct platform_device *pdev) { struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev); struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data; int gpio = pdata->gpio_vbus; regulator_put(gpio_vbus->vbus_draw); otg_set_transceiver(NULL); free_irq(gpio_to_irq(gpio), &pdev->dev); if (gpio_is_valid(pdata->gpio_pullup)) gpio_free(pdata->gpio_pullup); gpio_free(gpio); platform_set_drvdata(pdev, NULL); kfree(gpio_vbus); return 0; } /* NOTE: the gpio-vbus device may *NOT* be hotplugged */ MODULE_ALIAS("platform:gpio-vbus"); static struct platform_driver gpio_vbus_driver = { .driver = { .name = "gpio-vbus", .owner = THIS_MODULE, }, .remove = __exit_p(gpio_vbus_remove), }; static int __init gpio_vbus_init(void) { return platform_driver_probe(&gpio_vbus_driver, gpio_vbus_probe); } module_init(gpio_vbus_init); static void __exit gpio_vbus_exit(void) { platform_driver_unregister(&gpio_vbus_driver); } module_exit(gpio_vbus_exit); MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver"); MODULE_AUTHOR("Philipp Zabel"); MODULE_LICENSE("GPL");