1 // SPDX-License-Identifier: GPL-2.0-only
2 /**
3  * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver
4  *
5  * Copyright (C) 2015 Texas Instruments Incorporated - https://www.ti.com
6  * Author: Roger Quadros <rogerq@ti.com>
7  */
8 
9 #include <linux/extcon-provider.h>
10 #include <linux/gpio.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of_gpio.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/workqueue.h>
21 #include <linux/pinctrl/consumer.h>
22 
23 #define USB_GPIO_DEBOUNCE_MS	20	/* ms */
24 
25 struct usb_extcon_info {
26 	struct device *dev;
27 	struct extcon_dev *edev;
28 
29 	struct gpio_desc *id_gpiod;
30 	struct gpio_desc *vbus_gpiod;
31 	int id_irq;
32 	int vbus_irq;
33 
34 	unsigned long debounce_jiffies;
35 	struct delayed_work wq_detcable;
36 };
37 
38 static const unsigned int usb_extcon_cable[] = {
39 	EXTCON_USB,
40 	EXTCON_USB_HOST,
41 	EXTCON_NONE,
42 };
43 
44 /*
45  * "USB" = VBUS and "USB-HOST" = !ID, so we have:
46  * Both "USB" and "USB-HOST" can't be set as active at the
47  * same time so if "USB-HOST" is active (i.e. ID is 0)  we keep "USB" inactive
48  * even if VBUS is on.
49  *
50  *  State              |    ID   |   VBUS
51  * ----------------------------------------
52  *  [1] USB            |    H    |    H
53  *  [2] none           |    H    |    L
54  *  [3] USB-HOST       |    L    |    H
55  *  [4] USB-HOST       |    L    |    L
56  *
57  * In case we have only one of these signals:
58  * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1.
59  * - ID only - we want to distinguish between [1] and [4], so VBUS = ID.
60 */
61 static void usb_extcon_detect_cable(struct work_struct *work)
62 {
63 	int id, vbus;
64 	struct usb_extcon_info *info = container_of(to_delayed_work(work),
65 						    struct usb_extcon_info,
66 						    wq_detcable);
67 
68 	/* check ID and VBUS and update cable state */
69 	id = info->id_gpiod ?
70 		gpiod_get_value_cansleep(info->id_gpiod) : 1;
71 	vbus = info->vbus_gpiod ?
72 		gpiod_get_value_cansleep(info->vbus_gpiod) : id;
73 
74 	/* at first we clean states which are no longer active */
75 	if (id)
76 		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, false);
77 	if (!vbus)
78 		extcon_set_state_sync(info->edev, EXTCON_USB, false);
79 
80 	if (!id) {
81 		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, true);
82 	} else {
83 		if (vbus)
84 			extcon_set_state_sync(info->edev, EXTCON_USB, true);
85 	}
86 }
87 
88 static irqreturn_t usb_irq_handler(int irq, void *dev_id)
89 {
90 	struct usb_extcon_info *info = dev_id;
91 
92 	queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
93 			   info->debounce_jiffies);
94 
95 	return IRQ_HANDLED;
96 }
97 
98 static int usb_extcon_probe(struct platform_device *pdev)
99 {
100 	struct device *dev = &pdev->dev;
101 	struct device_node *np = dev->of_node;
102 	struct usb_extcon_info *info;
103 	int ret;
104 
105 	if (!np)
106 		return -EINVAL;
107 
108 	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
109 	if (!info)
110 		return -ENOMEM;
111 
112 	info->dev = dev;
113 	info->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", GPIOD_IN);
114 	info->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus",
115 						   GPIOD_IN);
116 
117 	if (!info->id_gpiod && !info->vbus_gpiod) {
118 		dev_err(dev, "failed to get gpios\n");
119 		return -ENODEV;
120 	}
121 
122 	if (IS_ERR(info->id_gpiod))
123 		return PTR_ERR(info->id_gpiod);
124 
125 	if (IS_ERR(info->vbus_gpiod))
126 		return PTR_ERR(info->vbus_gpiod);
127 
128 	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
129 	if (IS_ERR(info->edev)) {
130 		dev_err(dev, "failed to allocate extcon device\n");
131 		return -ENOMEM;
132 	}
133 
134 	ret = devm_extcon_dev_register(dev, info->edev);
135 	if (ret < 0) {
136 		dev_err(dev, "failed to register extcon device\n");
137 		return ret;
138 	}
139 
140 	if (info->id_gpiod)
141 		ret = gpiod_set_debounce(info->id_gpiod,
142 					 USB_GPIO_DEBOUNCE_MS * 1000);
143 	if (!ret && info->vbus_gpiod)
144 		ret = gpiod_set_debounce(info->vbus_gpiod,
145 					 USB_GPIO_DEBOUNCE_MS * 1000);
146 
147 	if (ret < 0)
148 		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);
149 
150 	INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);
151 
152 	if (info->id_gpiod) {
153 		info->id_irq = gpiod_to_irq(info->id_gpiod);
154 		if (info->id_irq < 0) {
155 			dev_err(dev, "failed to get ID IRQ\n");
156 			return info->id_irq;
157 		}
158 
159 		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
160 						usb_irq_handler,
161 						IRQF_TRIGGER_RISING |
162 						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
163 						pdev->name, info);
164 		if (ret < 0) {
165 			dev_err(dev, "failed to request handler for ID IRQ\n");
166 			return ret;
167 		}
168 	}
169 
170 	if (info->vbus_gpiod) {
171 		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
172 		if (info->vbus_irq < 0) {
173 			dev_err(dev, "failed to get VBUS IRQ\n");
174 			return info->vbus_irq;
175 		}
176 
177 		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
178 						usb_irq_handler,
179 						IRQF_TRIGGER_RISING |
180 						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
181 						pdev->name, info);
182 		if (ret < 0) {
183 			dev_err(dev, "failed to request handler for VBUS IRQ\n");
184 			return ret;
185 		}
186 	}
187 
188 	platform_set_drvdata(pdev, info);
189 	device_set_wakeup_capable(&pdev->dev, true);
190 
191 	/* Perform initial detection */
192 	usb_extcon_detect_cable(&info->wq_detcable.work);
193 
194 	return 0;
195 }
196 
197 static int usb_extcon_remove(struct platform_device *pdev)
198 {
199 	struct usb_extcon_info *info = platform_get_drvdata(pdev);
200 
201 	cancel_delayed_work_sync(&info->wq_detcable);
202 	device_init_wakeup(&pdev->dev, false);
203 
204 	return 0;
205 }
206 
207 #ifdef CONFIG_PM_SLEEP
208 static int usb_extcon_suspend(struct device *dev)
209 {
210 	struct usb_extcon_info *info = dev_get_drvdata(dev);
211 	int ret = 0;
212 
213 	if (device_may_wakeup(dev)) {
214 		if (info->id_gpiod) {
215 			ret = enable_irq_wake(info->id_irq);
216 			if (ret)
217 				return ret;
218 		}
219 		if (info->vbus_gpiod) {
220 			ret = enable_irq_wake(info->vbus_irq);
221 			if (ret) {
222 				if (info->id_gpiod)
223 					disable_irq_wake(info->id_irq);
224 
225 				return ret;
226 			}
227 		}
228 	}
229 
230 	/*
231 	 * We don't want to process any IRQs after this point
232 	 * as GPIOs used behind I2C subsystem might not be
233 	 * accessible until resume completes. So disable IRQ.
234 	 */
235 	if (info->id_gpiod)
236 		disable_irq(info->id_irq);
237 	if (info->vbus_gpiod)
238 		disable_irq(info->vbus_irq);
239 
240 	if (!device_may_wakeup(dev))
241 		pinctrl_pm_select_sleep_state(dev);
242 
243 	return ret;
244 }
245 
246 static int usb_extcon_resume(struct device *dev)
247 {
248 	struct usb_extcon_info *info = dev_get_drvdata(dev);
249 	int ret = 0;
250 
251 	if (!device_may_wakeup(dev))
252 		pinctrl_pm_select_default_state(dev);
253 
254 	if (device_may_wakeup(dev)) {
255 		if (info->id_gpiod) {
256 			ret = disable_irq_wake(info->id_irq);
257 			if (ret)
258 				return ret;
259 		}
260 		if (info->vbus_gpiod) {
261 			ret = disable_irq_wake(info->vbus_irq);
262 			if (ret) {
263 				if (info->id_gpiod)
264 					enable_irq_wake(info->id_irq);
265 
266 				return ret;
267 			}
268 		}
269 	}
270 
271 	if (info->id_gpiod)
272 		enable_irq(info->id_irq);
273 	if (info->vbus_gpiod)
274 		enable_irq(info->vbus_irq);
275 
276 	queue_delayed_work(system_power_efficient_wq,
277 			   &info->wq_detcable, 0);
278 
279 	return ret;
280 }
281 #endif
282 
283 static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops,
284 			 usb_extcon_suspend, usb_extcon_resume);
285 
286 static const struct of_device_id usb_extcon_dt_match[] = {
287 	{ .compatible = "linux,extcon-usb-gpio", },
288 	{ /* sentinel */ }
289 };
290 MODULE_DEVICE_TABLE(of, usb_extcon_dt_match);
291 
292 static const struct platform_device_id usb_extcon_platform_ids[] = {
293 	{ .name = "extcon-usb-gpio", },
294 	{ /* sentinel */ }
295 };
296 MODULE_DEVICE_TABLE(platform, usb_extcon_platform_ids);
297 
298 static struct platform_driver usb_extcon_driver = {
299 	.probe		= usb_extcon_probe,
300 	.remove		= usb_extcon_remove,
301 	.driver		= {
302 		.name	= "extcon-usb-gpio",
303 		.pm	= &usb_extcon_pm_ops,
304 		.of_match_table = usb_extcon_dt_match,
305 	},
306 	.id_table = usb_extcon_platform_ids,
307 };
308 
309 module_platform_driver(usb_extcon_driver);
310 
311 MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
312 MODULE_DESCRIPTION("USB GPIO extcon driver");
313 MODULE_LICENSE("GPL v2");
314