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73 	/* at first we clean states which are no longer active */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