1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * USB GPIO Based Connection Detection Driver
4 *
5 * Copyright (C) 2019 MediaTek Inc.
6 *
7 * Author: Chunfeng Yun <[email protected]>
8 *
9 * Some code borrowed from drivers/extcon/extcon-usb-gpio.c
10 */
11
12 #include <linux/device.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/pinctrl/consumer.h>
19 #include <linux/platform_device.h>
20 #include <linux/power_supply.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/string_choices.h>
23 #include <linux/usb/role.h>
24
25 #define USB_GPIO_DEB_MS 20 /* ms */
26 #define USB_GPIO_DEB_US ((USB_GPIO_DEB_MS) * 1000) /* us */
27
28 #define USB_CONN_IRQF \
29 (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)
30
31 struct usb_conn_info {
32 struct device *dev;
33 struct usb_role_switch *role_sw;
34 enum usb_role last_role;
35 struct regulator *vbus;
36 struct delayed_work dw_det;
37 unsigned long debounce_jiffies;
38
39 struct gpio_desc *id_gpiod;
40 struct gpio_desc *vbus_gpiod;
41 int id_irq;
42 int vbus_irq;
43
44 struct power_supply_desc desc;
45 struct power_supply *charger;
46 bool initial_detection;
47 };
48
49 /*
50 * "DEVICE" = VBUS and "HOST" = !ID, so we have:
51 * Both "DEVICE" and "HOST" can't be set as active at the same time
52 * so if "HOST" is active (i.e. ID is 0) we keep "DEVICE" inactive
53 * even if VBUS is on.
54 *
55 * Role | ID | VBUS
56 * ------------------------------------
57 * [1] DEVICE | H | H
58 * [2] NONE | H | L
59 * [3] HOST | L | H
60 * [4] HOST | L | L
61 *
62 * In case we have only one of these signals:
63 * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1
64 * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
65 */
usb_conn_detect_cable(struct work_struct * work)66 static void usb_conn_detect_cable(struct work_struct *work)
67 {
68 struct usb_conn_info *info;
69 enum usb_role role;
70 int id, vbus, ret;
71
72 info = container_of(to_delayed_work(work),
73 struct usb_conn_info, dw_det);
74
75 /* check ID and VBUS */
76 id = info->id_gpiod ?
77 gpiod_get_value_cansleep(info->id_gpiod) : 1;
78 vbus = info->vbus_gpiod ?
79 gpiod_get_value_cansleep(info->vbus_gpiod) : id;
80
81 if (!id)
82 role = USB_ROLE_HOST;
83 else if (vbus)
84 role = USB_ROLE_DEVICE;
85 else
86 role = USB_ROLE_NONE;
87
88 dev_dbg(info->dev, "role %s -> %s, gpios: id %d, vbus %d\n",
89 usb_role_string(info->last_role), usb_role_string(role), id, vbus);
90
91 if (!info->initial_detection && info->last_role == role) {
92 dev_warn(info->dev, "repeated role: %s\n", usb_role_string(role));
93 return;
94 }
95
96 info->initial_detection = false;
97
98 if (info->last_role == USB_ROLE_HOST && info->vbus)
99 regulator_disable(info->vbus);
100
101 ret = usb_role_switch_set_role(info->role_sw, role);
102 if (ret)
103 dev_err(info->dev, "failed to set role: %d\n", ret);
104
105 if (role == USB_ROLE_HOST && info->vbus) {
106 ret = regulator_enable(info->vbus);
107 if (ret)
108 dev_err(info->dev, "enable vbus regulator failed\n");
109 }
110
111 info->last_role = role;
112
113 if (info->vbus)
114 dev_dbg(info->dev, "vbus regulator is %s\n",
115 str_enabled_disabled(regulator_is_enabled(info->vbus)));
116
117 power_supply_changed(info->charger);
118 }
119
usb_conn_queue_dwork(struct usb_conn_info * info,unsigned long delay)120 static void usb_conn_queue_dwork(struct usb_conn_info *info,
121 unsigned long delay)
122 {
123 queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);
124 }
125
usb_conn_isr(int irq,void * dev_id)126 static irqreturn_t usb_conn_isr(int irq, void *dev_id)
127 {
128 struct usb_conn_info *info = dev_id;
129
130 usb_conn_queue_dwork(info, info->debounce_jiffies);
131
132 return IRQ_HANDLED;
133 }
134
135 static enum power_supply_property usb_charger_properties[] = {
136 POWER_SUPPLY_PROP_ONLINE,
137 };
138
usb_charger_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)139 static int usb_charger_get_property(struct power_supply *psy,
140 enum power_supply_property psp,
141 union power_supply_propval *val)
142 {
143 struct usb_conn_info *info = power_supply_get_drvdata(psy);
144
145 switch (psp) {
146 case POWER_SUPPLY_PROP_ONLINE:
147 val->intval = info->last_role == USB_ROLE_DEVICE;
148 break;
149 default:
150 return -EINVAL;
151 }
152
153 return 0;
154 }
155
usb_conn_psy_register(struct usb_conn_info * info)156 static int usb_conn_psy_register(struct usb_conn_info *info)
157 {
158 struct device *dev = info->dev;
159 struct power_supply_desc *desc = &info->desc;
160 struct power_supply_config cfg = {
161 .of_node = dev->of_node,
162 };
163
164 desc->name = "usb-charger";
165 desc->properties = usb_charger_properties;
166 desc->num_properties = ARRAY_SIZE(usb_charger_properties);
167 desc->get_property = usb_charger_get_property;
168 desc->type = POWER_SUPPLY_TYPE_USB;
169 cfg.drv_data = info;
170
171 info->charger = devm_power_supply_register(dev, desc, &cfg);
172 if (IS_ERR(info->charger))
173 dev_err(dev, "Unable to register charger\n");
174
175 return PTR_ERR_OR_ZERO(info->charger);
176 }
177
usb_conn_probe(struct platform_device * pdev)178 static int usb_conn_probe(struct platform_device *pdev)
179 {
180 struct device *dev = &pdev->dev;
181 struct usb_conn_info *info;
182 int ret = 0;
183
184 info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
185 if (!info)
186 return -ENOMEM;
187
188 info->dev = dev;
189 info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
190 if (IS_ERR(info->id_gpiod))
191 return PTR_ERR(info->id_gpiod);
192
193 info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
194 if (IS_ERR(info->vbus_gpiod))
195 return PTR_ERR(info->vbus_gpiod);
196
197 if (!info->id_gpiod && !info->vbus_gpiod) {
198 dev_err(dev, "failed to get gpios\n");
199 return -ENODEV;
200 }
201
202 if (info->id_gpiod)
203 ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
204 if (!ret && info->vbus_gpiod)
205 ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
206 if (ret < 0)
207 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
208
209 INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
210
211 info->vbus = devm_regulator_get_optional(dev, "vbus");
212 if (PTR_ERR(info->vbus) == -ENODEV)
213 info->vbus = NULL;
214
215 if (IS_ERR(info->vbus))
216 return dev_err_probe(dev, PTR_ERR(info->vbus), "failed to get vbus\n");
217
218 info->role_sw = usb_role_switch_get(dev);
219 if (IS_ERR(info->role_sw))
220 return dev_err_probe(dev, PTR_ERR(info->role_sw),
221 "failed to get role switch\n");
222
223 ret = usb_conn_psy_register(info);
224 if (ret)
225 goto put_role_sw;
226
227 if (info->id_gpiod) {
228 info->id_irq = gpiod_to_irq(info->id_gpiod);
229 if (info->id_irq < 0) {
230 dev_err(dev, "failed to get ID IRQ\n");
231 ret = info->id_irq;
232 goto put_role_sw;
233 }
234
235 ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
236 usb_conn_isr, USB_CONN_IRQF,
237 pdev->name, info);
238 if (ret < 0) {
239 dev_err(dev, "failed to request ID IRQ\n");
240 goto put_role_sw;
241 }
242 }
243
244 if (info->vbus_gpiod) {
245 info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
246 if (info->vbus_irq < 0) {
247 dev_err(dev, "failed to get VBUS IRQ\n");
248 ret = info->vbus_irq;
249 goto put_role_sw;
250 }
251
252 ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
253 usb_conn_isr, USB_CONN_IRQF,
254 pdev->name, info);
255 if (ret < 0) {
256 dev_err(dev, "failed to request VBUS IRQ\n");
257 goto put_role_sw;
258 }
259 }
260
261 platform_set_drvdata(pdev, info);
262 device_set_wakeup_capable(&pdev->dev, true);
263
264 /* Perform initial detection */
265 info->initial_detection = true;
266 usb_conn_queue_dwork(info, 0);
267
268 return 0;
269
270 put_role_sw:
271 usb_role_switch_put(info->role_sw);
272 return ret;
273 }
274
usb_conn_remove(struct platform_device * pdev)275 static void usb_conn_remove(struct platform_device *pdev)
276 {
277 struct usb_conn_info *info = platform_get_drvdata(pdev);
278
279 cancel_delayed_work_sync(&info->dw_det);
280
281 if (info->last_role == USB_ROLE_HOST && info->vbus)
282 regulator_disable(info->vbus);
283
284 usb_role_switch_put(info->role_sw);
285 }
286
usb_conn_suspend(struct device * dev)287 static int __maybe_unused usb_conn_suspend(struct device *dev)
288 {
289 struct usb_conn_info *info = dev_get_drvdata(dev);
290
291 if (device_may_wakeup(dev)) {
292 if (info->id_gpiod)
293 enable_irq_wake(info->id_irq);
294 if (info->vbus_gpiod)
295 enable_irq_wake(info->vbus_irq);
296 return 0;
297 }
298
299 if (info->id_gpiod)
300 disable_irq(info->id_irq);
301 if (info->vbus_gpiod)
302 disable_irq(info->vbus_irq);
303
304 pinctrl_pm_select_sleep_state(dev);
305
306 return 0;
307 }
308
usb_conn_resume(struct device * dev)309 static int __maybe_unused usb_conn_resume(struct device *dev)
310 {
311 struct usb_conn_info *info = dev_get_drvdata(dev);
312
313 if (device_may_wakeup(dev)) {
314 if (info->id_gpiod)
315 disable_irq_wake(info->id_irq);
316 if (info->vbus_gpiod)
317 disable_irq_wake(info->vbus_irq);
318 return 0;
319 }
320
321 pinctrl_pm_select_default_state(dev);
322
323 if (info->id_gpiod)
324 enable_irq(info->id_irq);
325 if (info->vbus_gpiod)
326 enable_irq(info->vbus_irq);
327
328 usb_conn_queue_dwork(info, 0);
329
330 return 0;
331 }
332
333 static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
334 usb_conn_suspend, usb_conn_resume);
335
336 static const struct of_device_id usb_conn_dt_match[] = {
337 { .compatible = "gpio-usb-b-connector", },
338 { }
339 };
340 MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
341
342 static struct platform_driver usb_conn_driver = {
343 .probe = usb_conn_probe,
344 .remove = usb_conn_remove,
345 .driver = {
346 .name = "usb-conn-gpio",
347 .pm = &usb_conn_pm_ops,
348 .of_match_table = usb_conn_dt_match,
349 },
350 };
351
352 module_platform_driver(usb_conn_driver);
353
354 MODULE_AUTHOR("Chunfeng Yun <[email protected]>");
355 MODULE_DESCRIPTION("USB GPIO based connection detection driver");
356 MODULE_LICENSE("GPL v2");
357