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