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Linux/drivers/usb/phy/phy-gpio-vbus-usb.c

  1 /*
  2  * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
  3  *
  4  * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  */
 10 
 11 #include <linux/kernel.h>
 12 #include <linux/platform_device.h>
 13 #include <linux/gpio.h>
 14 #include <linux/module.h>
 15 #include <linux/slab.h>
 16 #include <linux/interrupt.h>
 17 #include <linux/usb.h>
 18 #include <linux/workqueue.h>
 19 
 20 #include <linux/regulator/consumer.h>
 21 
 22 #include <linux/usb/gadget.h>
 23 #include <linux/usb/gpio_vbus.h>
 24 #include <linux/usb/otg.h>
 25 
 26 
 27 /*
 28  * A simple GPIO VBUS sensing driver for B peripheral only devices
 29  * with internal transceivers. It can control a D+ pullup GPIO and
 30  * a regulator to limit the current drawn from VBUS.
 31  *
 32  * Needs to be loaded before the UDC driver that will use it.
 33  */
 34 struct gpio_vbus_data {
 35         struct usb_phy          phy;
 36         struct device          *dev;
 37         struct regulator       *vbus_draw;
 38         int                     vbus_draw_enabled;
 39         unsigned                mA;
 40         struct delayed_work     work;
 41         int                     vbus;
 42         int                     irq;
 43 };
 44 
 45 
 46 /*
 47  * This driver relies on "both edges" triggering.  VBUS has 100 msec to
 48  * stabilize, so the peripheral controller driver may need to cope with
 49  * some bouncing due to current surges (e.g. charging local capacitance)
 50  * and contact chatter.
 51  *
 52  * REVISIT in desperate straits, toggling between rising and falling
 53  * edges might be workable.
 54  */
 55 #define VBUS_IRQ_FLAGS \
 56         (IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
 57 
 58 
 59 /* interface to regulator framework */
 60 static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
 61 {
 62         struct regulator *vbus_draw = gpio_vbus->vbus_draw;
 63         int enabled;
 64         int ret;
 65 
 66         if (!vbus_draw)
 67                 return;
 68 
 69         enabled = gpio_vbus->vbus_draw_enabled;
 70         if (mA) {
 71                 regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
 72                 if (!enabled) {
 73                         ret = regulator_enable(vbus_draw);
 74                         if (ret < 0)
 75                                 return;
 76                         gpio_vbus->vbus_draw_enabled = 1;
 77                 }
 78         } else {
 79                 if (enabled) {
 80                         ret = regulator_disable(vbus_draw);
 81                         if (ret < 0)
 82                                 return;
 83                         gpio_vbus->vbus_draw_enabled = 0;
 84                 }
 85         }
 86         gpio_vbus->mA = mA;
 87 }
 88 
 89 static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
 90 {
 91         int vbus;
 92 
 93         vbus = gpio_get_value(pdata->gpio_vbus);
 94         if (pdata->gpio_vbus_inverted)
 95                 vbus = !vbus;
 96 
 97         return vbus;
 98 }
 99 
100 static void gpio_vbus_work(struct work_struct *work)
101 {
102         struct gpio_vbus_data *gpio_vbus =
103                 container_of(work, struct gpio_vbus_data, work.work);
104         struct gpio_vbus_mach_info *pdata = dev_get_platdata(gpio_vbus->dev);
105         int gpio, status, vbus;
106 
107         if (!gpio_vbus->phy.otg->gadget)
108                 return;
109 
110         vbus = is_vbus_powered(pdata);
111         if ((vbus ^ gpio_vbus->vbus) == 0)
112                 return;
113         gpio_vbus->vbus = vbus;
114 
115         /* Peripheral controllers which manage the pullup themselves won't have
116          * gpio_pullup configured here.  If it's configured here, we'll do what
117          * isp1301_omap::b_peripheral() does and enable the pullup here... although
118          * that may complicate usb_gadget_{,dis}connect() support.
119          */
120         gpio = pdata->gpio_pullup;
121 
122         if (vbus) {
123                 status = USB_EVENT_VBUS;
124                 gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
125                 gpio_vbus->phy.last_event = status;
126                 usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
127 
128                 /* drawing a "unit load" is *always* OK, except for OTG */
129                 set_vbus_draw(gpio_vbus, 100);
130 
131                 /* optionally enable D+ pullup */
132                 if (gpio_is_valid(gpio))
133                         gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
134 
135                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
136                                            status, gpio_vbus->phy.otg->gadget);
137         } else {
138                 /* optionally disable D+ pullup */
139                 if (gpio_is_valid(gpio))
140                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
141 
142                 set_vbus_draw(gpio_vbus, 0);
143 
144                 usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
145                 status = USB_EVENT_NONE;
146                 gpio_vbus->phy.state = OTG_STATE_B_IDLE;
147                 gpio_vbus->phy.last_event = status;
148 
149                 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
150                                            status, gpio_vbus->phy.otg->gadget);
151         }
152 }
153 
154 /* VBUS change IRQ handler */
155 static irqreturn_t gpio_vbus_irq(int irq, void *data)
156 {
157         struct platform_device *pdev = data;
158         struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
159         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
160         struct usb_otg *otg = gpio_vbus->phy.otg;
161 
162         dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
163                 is_vbus_powered(pdata) ? "supplied" : "inactive",
164                 otg->gadget ? otg->gadget->name : "none");
165 
166         if (otg->gadget)
167                 schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
168 
169         return IRQ_HANDLED;
170 }
171 
172 /* OTG transceiver interface */
173 
174 /* bind/unbind the peripheral controller */
175 static int gpio_vbus_set_peripheral(struct usb_otg *otg,
176                                         struct usb_gadget *gadget)
177 {
178         struct gpio_vbus_data *gpio_vbus;
179         struct gpio_vbus_mach_info *pdata;
180         struct platform_device *pdev;
181         int gpio;
182 
183         gpio_vbus = container_of(otg->phy, struct gpio_vbus_data, phy);
184         pdev = to_platform_device(gpio_vbus->dev);
185         pdata = dev_get_platdata(gpio_vbus->dev);
186         gpio = pdata->gpio_pullup;
187 
188         if (!gadget) {
189                 dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
190                         otg->gadget->name);
191 
192                 /* optionally disable D+ pullup */
193                 if (gpio_is_valid(gpio))
194                         gpio_set_value(gpio, pdata->gpio_pullup_inverted);
195 
196                 set_vbus_draw(gpio_vbus, 0);
197 
198                 usb_gadget_vbus_disconnect(otg->gadget);
199                 otg->phy->state = OTG_STATE_UNDEFINED;
200 
201                 otg->gadget = NULL;
202                 return 0;
203         }
204 
205         otg->gadget = gadget;
206         dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
207 
208         /* initialize connection state */
209         gpio_vbus->vbus = 0; /* start with disconnected */
210         gpio_vbus_irq(gpio_vbus->irq, pdev);
211         return 0;
212 }
213 
214 /* effective for B devices, ignored for A-peripheral */
215 static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
216 {
217         struct gpio_vbus_data *gpio_vbus;
218 
219         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
220 
221         if (phy->state == OTG_STATE_B_PERIPHERAL)
222                 set_vbus_draw(gpio_vbus, mA);
223         return 0;
224 }
225 
226 /* for non-OTG B devices: set/clear transceiver suspend mode */
227 static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
228 {
229         struct gpio_vbus_data *gpio_vbus;
230 
231         gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
232 
233         /* draw max 0 mA from vbus in suspend mode; or the previously
234          * recorded amount of current if not suspended
235          *
236          * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
237          * if they're wake-enabled ... we don't handle that yet.
238          */
239         return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
240 }
241 
242 /* platform driver interface */
243 
244 static int gpio_vbus_probe(struct platform_device *pdev)
245 {
246         struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
247         struct gpio_vbus_data *gpio_vbus;
248         struct resource *res;
249         int err, gpio, irq;
250         unsigned long irqflags;
251 
252         if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
253                 return -EINVAL;
254         gpio = pdata->gpio_vbus;
255 
256         gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
257                                  GFP_KERNEL);
258         if (!gpio_vbus)
259                 return -ENOMEM;
260 
261         gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
262                                           GFP_KERNEL);
263         if (!gpio_vbus->phy.otg)
264                 return -ENOMEM;
265 
266         platform_set_drvdata(pdev, gpio_vbus);
267         gpio_vbus->dev = &pdev->dev;
268         gpio_vbus->phy.label = "gpio-vbus";
269         gpio_vbus->phy.dev = gpio_vbus->dev;
270         gpio_vbus->phy.set_power = gpio_vbus_set_power;
271         gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
272         gpio_vbus->phy.state = OTG_STATE_UNDEFINED;
273 
274         gpio_vbus->phy.otg->phy = &gpio_vbus->phy;
275         gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
276 
277         err = devm_gpio_request(&pdev->dev, gpio, "vbus_detect");
278         if (err) {
279                 dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
280                         gpio, err);
281                 return err;
282         }
283         gpio_direction_input(gpio);
284 
285         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
286         if (res) {
287                 irq = res->start;
288                 irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
289         } else {
290                 irq = gpio_to_irq(gpio);
291                 irqflags = VBUS_IRQ_FLAGS;
292         }
293 
294         gpio_vbus->irq = irq;
295 
296         /* if data line pullup is in use, initialize it to "not pulling up" */
297         gpio = pdata->gpio_pullup;
298         if (gpio_is_valid(gpio)) {
299                 err = devm_gpio_request(&pdev->dev, gpio, "udc_pullup");
300                 if (err) {
301                         dev_err(&pdev->dev,
302                                 "can't request pullup gpio %d, err: %d\n",
303                                 gpio, err);
304                         return err;
305                 }
306                 gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
307         }
308 
309         err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
310                                "vbus_detect", pdev);
311         if (err) {
312                 dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
313                         irq, err);
314                 return err;
315         }
316 
317         INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
318 
319         gpio_vbus->vbus_draw = devm_regulator_get(&pdev->dev, "vbus_draw");
320         if (IS_ERR(gpio_vbus->vbus_draw)) {
321                 dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
322                         PTR_ERR(gpio_vbus->vbus_draw));
323                 gpio_vbus->vbus_draw = NULL;
324         }
325 
326         /* only active when a gadget is registered */
327         err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
328         if (err) {
329                 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
330                         err);
331                 return err;
332         }
333 
334         device_init_wakeup(&pdev->dev, pdata->wakeup);
335 
336         return 0;
337 }
338 
339 static int gpio_vbus_remove(struct platform_device *pdev)
340 {
341         struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
342 
343         device_init_wakeup(&pdev->dev, 0);
344         cancel_delayed_work_sync(&gpio_vbus->work);
345 
346         usb_remove_phy(&gpio_vbus->phy);
347 
348         return 0;
349 }
350 
351 #ifdef CONFIG_PM
352 static int gpio_vbus_pm_suspend(struct device *dev)
353 {
354         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
355 
356         if (device_may_wakeup(dev))
357                 enable_irq_wake(gpio_vbus->irq);
358 
359         return 0;
360 }
361 
362 static int gpio_vbus_pm_resume(struct device *dev)
363 {
364         struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
365 
366         if (device_may_wakeup(dev))
367                 disable_irq_wake(gpio_vbus->irq);
368 
369         return 0;
370 }
371 
372 static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
373         .suspend        = gpio_vbus_pm_suspend,
374         .resume         = gpio_vbus_pm_resume,
375 };
376 #endif
377 
378 MODULE_ALIAS("platform:gpio-vbus");
379 
380 static struct platform_driver gpio_vbus_driver = {
381         .driver = {
382                 .name  = "gpio-vbus",
383                 .owner = THIS_MODULE,
384 #ifdef CONFIG_PM
385                 .pm = &gpio_vbus_dev_pm_ops,
386 #endif
387         },
388         .probe          = gpio_vbus_probe,
389         .remove         = gpio_vbus_remove,
390 };
391 
392 module_platform_driver(gpio_vbus_driver);
393 
394 MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
395 MODULE_AUTHOR("Philipp Zabel");
396 MODULE_LICENSE("GPL");
397 

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