2 * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
4 * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
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.
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>
20 #include <linux/regulator/consumer.h>
22 #include <linux/usb/gadget.h>
23 #include <linux/usb/gpio_vbus.h>
24 #include <linux/usb/otg.h>
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.
32 * Needs to be loaded before the UDC driver that will use it.
34 struct gpio_vbus_data {
37 struct regulator *vbus_draw;
38 int vbus_draw_enabled;
40 struct work_struct work;
45 * This driver relies on "both edges" triggering. VBUS has 100 msec to
46 * stabilize, so the peripheral controller driver may need to cope with
47 * some bouncing due to current surges (e.g. charging local capacitance)
48 * and contact chatter.
50 * REVISIT in desperate straits, toggling between rising and falling
51 * edges might be workable.
53 #define VBUS_IRQ_FLAGS \
54 ( IRQF_SAMPLE_RANDOM | IRQF_SHARED \
55 | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING )
58 /* interface to regulator framework */
59 static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
61 struct regulator *vbus_draw = gpio_vbus->vbus_draw;
67 enabled = gpio_vbus->vbus_draw_enabled;
69 regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
71 regulator_enable(vbus_draw);
72 gpio_vbus->vbus_draw_enabled = 1;
76 regulator_disable(vbus_draw);
77 gpio_vbus->vbus_draw_enabled = 0;
83 static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
87 vbus = gpio_get_value(pdata->gpio_vbus);
88 if (pdata->gpio_vbus_inverted)
94 static void gpio_vbus_work(struct work_struct *work)
96 struct gpio_vbus_data *gpio_vbus =
97 container_of(work, struct gpio_vbus_data, work);
98 struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
101 if (!gpio_vbus->phy.otg->gadget)
104 /* Peripheral controllers which manage the pullup themselves won't have
105 * gpio_pullup configured here. If it's configured here, we'll do what
106 * isp1301_omap::b_peripheral() does and enable the pullup here... although
107 * that may complicate usb_gadget_{,dis}connect() support.
109 gpio = pdata->gpio_pullup;
110 if (is_vbus_powered(pdata)) {
111 gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
112 usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
114 /* drawing a "unit load" is *always* OK, except for OTG */
115 set_vbus_draw(gpio_vbus, 100);
117 /* optionally enable D+ pullup */
118 if (gpio_is_valid(gpio))
119 gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
121 /* optionally disable D+ pullup */
122 if (gpio_is_valid(gpio))
123 gpio_set_value(gpio, pdata->gpio_pullup_inverted);
125 set_vbus_draw(gpio_vbus, 0);
127 usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
128 gpio_vbus->phy.state = OTG_STATE_B_IDLE;
132 /* VBUS change IRQ handler */
133 static irqreturn_t gpio_vbus_irq(int irq, void *data)
135 struct platform_device *pdev = data;
136 struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
137 struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
138 struct usb_otg *otg = gpio_vbus->phy.otg;
140 dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
141 is_vbus_powered(pdata) ? "supplied" : "inactive",
142 otg->gadget ? otg->gadget->name : "none");
145 schedule_work(&gpio_vbus->work);
150 /* OTG transceiver interface */
152 /* bind/unbind the peripheral controller */
153 static int gpio_vbus_set_peripheral(struct usb_otg *otg,
154 struct usb_gadget *gadget)
156 struct gpio_vbus_data *gpio_vbus;
157 struct gpio_vbus_mach_info *pdata;
158 struct platform_device *pdev;
161 gpio_vbus = container_of(otg->phy, struct gpio_vbus_data, phy);
162 pdev = to_platform_device(gpio_vbus->dev);
163 pdata = gpio_vbus->dev->platform_data;
164 irq = gpio_to_irq(pdata->gpio_vbus);
165 gpio = pdata->gpio_pullup;
168 dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
171 /* optionally disable D+ pullup */
172 if (gpio_is_valid(gpio))
173 gpio_set_value(gpio, pdata->gpio_pullup_inverted);
175 set_vbus_draw(gpio_vbus, 0);
177 usb_gadget_vbus_disconnect(otg->gadget);
178 otg->phy->state = OTG_STATE_UNDEFINED;
184 otg->gadget = gadget;
185 dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
187 /* initialize connection state */
188 gpio_vbus_irq(irq, pdev);
192 /* effective for B devices, ignored for A-peripheral */
193 static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
195 struct gpio_vbus_data *gpio_vbus;
197 gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
199 if (phy->state == OTG_STATE_B_PERIPHERAL)
200 set_vbus_draw(gpio_vbus, mA);
204 /* for non-OTG B devices: set/clear transceiver suspend mode */
205 static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
207 struct gpio_vbus_data *gpio_vbus;
209 gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
211 /* draw max 0 mA from vbus in suspend mode; or the previously
212 * recorded amount of current if not suspended
214 * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
215 * if they're wake-enabled ... we don't handle that yet.
217 return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
220 /* platform driver interface */
222 static int __init gpio_vbus_probe(struct platform_device *pdev)
224 struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
225 struct gpio_vbus_data *gpio_vbus;
226 struct resource *res;
229 if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
231 gpio = pdata->gpio_vbus;
233 gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
237 gpio_vbus->phy.otg = kzalloc(sizeof(struct usb_otg), GFP_KERNEL);
238 if (!gpio_vbus->phy.otg) {
243 platform_set_drvdata(pdev, gpio_vbus);
244 gpio_vbus->dev = &pdev->dev;
245 gpio_vbus->phy.label = "gpio-vbus";
246 gpio_vbus->phy.set_power = gpio_vbus_set_power;
247 gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
248 gpio_vbus->phy.state = OTG_STATE_UNDEFINED;
250 gpio_vbus->phy.otg->phy = &gpio_vbus->phy;
251 gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
253 err = gpio_request(gpio, "vbus_detect");
255 dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
259 gpio_direction_input(gpio);
261 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
264 res->flags &= IRQF_TRIGGER_MASK;
265 res->flags |= IRQF_SAMPLE_RANDOM | IRQF_SHARED;
267 irq = gpio_to_irq(gpio);
269 /* if data line pullup is in use, initialize it to "not pulling up" */
270 gpio = pdata->gpio_pullup;
271 if (gpio_is_valid(gpio)) {
272 err = gpio_request(gpio, "udc_pullup");
275 "can't request pullup gpio %d, err: %d\n",
277 gpio_free(pdata->gpio_vbus);
280 gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
283 err = request_irq(irq, gpio_vbus_irq, VBUS_IRQ_FLAGS,
284 "vbus_detect", pdev);
286 dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
290 INIT_WORK(&gpio_vbus->work, gpio_vbus_work);
292 gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
293 if (IS_ERR(gpio_vbus->vbus_draw)) {
294 dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
295 PTR_ERR(gpio_vbus->vbus_draw));
296 gpio_vbus->vbus_draw = NULL;
299 /* only active when a gadget is registered */
300 err = usb_set_transceiver(&gpio_vbus->phy);
302 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
309 free_irq(irq, &pdev->dev);
311 if (gpio_is_valid(pdata->gpio_pullup))
312 gpio_free(pdata->gpio_pullup);
313 gpio_free(pdata->gpio_vbus);
315 platform_set_drvdata(pdev, NULL);
316 kfree(gpio_vbus->phy.otg);
321 static int __exit gpio_vbus_remove(struct platform_device *pdev)
323 struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
324 struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
325 int gpio = pdata->gpio_vbus;
327 regulator_put(gpio_vbus->vbus_draw);
329 usb_set_transceiver(NULL);
331 free_irq(gpio_to_irq(gpio), &pdev->dev);
332 if (gpio_is_valid(pdata->gpio_pullup))
333 gpio_free(pdata->gpio_pullup);
335 platform_set_drvdata(pdev, NULL);
336 kfree(gpio_vbus->phy.otg);
342 /* NOTE: the gpio-vbus device may *NOT* be hotplugged */
344 MODULE_ALIAS("platform:gpio-vbus");
346 static struct platform_driver gpio_vbus_driver = {
349 .owner = THIS_MODULE,
351 .remove = __exit_p(gpio_vbus_remove),
354 static int __init gpio_vbus_init(void)
356 return platform_driver_probe(&gpio_vbus_driver, gpio_vbus_probe);
358 module_init(gpio_vbus_init);
360 static void __exit gpio_vbus_exit(void)
362 platform_driver_unregister(&gpio_vbus_driver);
364 module_exit(gpio_vbus_exit);
366 MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
367 MODULE_AUTHOR("Philipp Zabel");
368 MODULE_LICENSE("GPL");