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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 <chunfeng.yun@mediatek.com>
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/usb/role.h>
23
24#define USB_GPIO_DEB_MS 20 /* ms */
25#define USB_GPIO_DEB_US ((USB_GPIO_DEB_MS) * 1000) /* us */
26
27#define USB_CONN_IRQF \
28 (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)
29
30struct usb_conn_info {
31 struct device *dev;
32 struct usb_role_switch *role_sw;
33 enum usb_role last_role;
34 struct regulator *vbus;
35 struct delayed_work dw_det;
36 unsigned long debounce_jiffies;
37
38 struct gpio_desc *id_gpiod;
39 struct gpio_desc *vbus_gpiod;
40 int id_irq;
41 int vbus_irq;
42
43 struct power_supply_desc desc;
44 struct power_supply *charger;
45};
46
47/*
48 * "DEVICE" = VBUS and "HOST" = !ID, so we have:
49 * Both "DEVICE" and "HOST" can't be set as active at the same time
50 * so if "HOST" is active (i.e. ID is 0) we keep "DEVICE" inactive
51 * even if VBUS is on.
52 *
53 * Role | ID | VBUS
54 * ------------------------------------
55 * [1] DEVICE | H | H
56 * [2] NONE | H | L
57 * [3] HOST | L | H
58 * [4] HOST | L | L
59 *
60 * In case we have only one of these signals:
61 * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1
62 * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
63 */
64static void usb_conn_detect_cable(struct work_struct *work)
65{
66 struct usb_conn_info *info;
67 enum usb_role role;
68 int id, vbus, ret;
69
70 info = container_of(to_delayed_work(work),
71 struct usb_conn_info, dw_det);
72
73 /* check ID and VBUS */
74 id = info->id_gpiod ?
75 gpiod_get_value_cansleep(info->id_gpiod) : 1;
76 vbus = info->vbus_gpiod ?
77 gpiod_get_value_cansleep(info->vbus_gpiod) : id;
78
79 if (!id)
80 role = USB_ROLE_HOST;
81 else if (vbus)
82 role = USB_ROLE_DEVICE;
83 else
84 role = USB_ROLE_NONE;
85
86 dev_dbg(info->dev, "role %s -> %s, gpios: id %d, vbus %d\n",
87 usb_role_string(info->last_role), usb_role_string(role), id, vbus);
88
89 if (info->last_role == role) {
90 dev_warn(info->dev, "repeated role: %s\n", usb_role_string(role));
91 return;
92 }
93
94 if (info->last_role == USB_ROLE_HOST && info->vbus)
95 regulator_disable(info->vbus);
96
97 ret = usb_role_switch_set_role(info->role_sw, role);
98 if (ret)
99 dev_err(info->dev, "failed to set role: %d\n", ret);
100
101 if (role == USB_ROLE_HOST && info->vbus) {
102 ret = regulator_enable(info->vbus);
103 if (ret)
104 dev_err(info->dev, "enable vbus regulator failed\n");
105 }
106
107 info->last_role = role;
108
109 if (info->vbus)
110 dev_dbg(info->dev, "vbus regulator is %s\n",
111 regulator_is_enabled(info->vbus) ? "enabled" : "disabled");
112
113 power_supply_changed(info->charger);
114}
115
116static void usb_conn_queue_dwork(struct usb_conn_info *info,
117 unsigned long delay)
118{
119 queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);
120}
121
122static irqreturn_t usb_conn_isr(int irq, void *dev_id)
123{
124 struct usb_conn_info *info = dev_id;
125
126 usb_conn_queue_dwork(info, info->debounce_jiffies);
127
128 return IRQ_HANDLED;
129}
130
131static enum power_supply_property usb_charger_properties[] = {
132 POWER_SUPPLY_PROP_ONLINE,
133};
134
135static int usb_charger_get_property(struct power_supply *psy,
136 enum power_supply_property psp,
137 union power_supply_propval *val)
138{
139 struct usb_conn_info *info = power_supply_get_drvdata(psy);
140
141 switch (psp) {
142 case POWER_SUPPLY_PROP_ONLINE:
143 val->intval = info->last_role == USB_ROLE_DEVICE;
144 break;
145 default:
146 return -EINVAL;
147 }
148
149 return 0;
150}
151
152static int usb_conn_psy_register(struct usb_conn_info *info)
153{
154 struct device *dev = info->dev;
155 struct power_supply_desc *desc = &info->desc;
156 struct power_supply_config cfg = {
157 .of_node = dev->of_node,
158 };
159
160 desc->name = "usb-charger";
161 desc->properties = usb_charger_properties;
162 desc->num_properties = ARRAY_SIZE(usb_charger_properties);
163 desc->get_property = usb_charger_get_property;
164 desc->type = POWER_SUPPLY_TYPE_USB;
165 cfg.drv_data = info;
166
167 info->charger = devm_power_supply_register(dev, desc, &cfg);
168 if (IS_ERR(info->charger))
169 dev_err(dev, "Unable to register charger\n");
170
171 return PTR_ERR_OR_ZERO(info->charger);
172}
173
174static int usb_conn_probe(struct platform_device *pdev)
175{
176 struct device *dev = &pdev->dev;
177 struct usb_conn_info *info;
178 bool need_vbus = true;
179 int ret = 0;
180
181 info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
182 if (!info)
183 return -ENOMEM;
184
185 info->dev = dev;
186 info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
187 if (IS_ERR(info->id_gpiod))
188 return PTR_ERR(info->id_gpiod);
189
190 info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
191 if (IS_ERR(info->vbus_gpiod))
192 return PTR_ERR(info->vbus_gpiod);
193
194 if (!info->id_gpiod && !info->vbus_gpiod) {
195 dev_err(dev, "failed to get gpios\n");
196 return -ENODEV;
197 }
198
199 if (info->id_gpiod)
200 ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
201 if (!ret && info->vbus_gpiod)
202 ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
203 if (ret < 0)
204 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
205
206 INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
207
208 /*
209 * If the USB connector is a child of a USB port and that port already provides the VBUS
210 * supply, there's no need for the USB connector to provide it again.
211 */
212 if (dev->parent && dev->parent->of_node) {
213 if (of_find_property(dev->parent->of_node, "vbus-supply", NULL))
214 need_vbus = false;
215 }
216
217 if (!need_vbus) {
218 info->vbus = devm_regulator_get_optional(dev, "vbus");
219 if (PTR_ERR(info->vbus) == -ENODEV)
220 info->vbus = NULL;
221 } else {
222 info->vbus = devm_regulator_get(dev, "vbus");
223 }
224
225 if (IS_ERR(info->vbus)) {
226 ret = PTR_ERR(info->vbus);
227 return dev_err_probe(dev, ret, "failed to get vbus :%d\n", ret);
228 }
229
230 info->role_sw = usb_role_switch_get(dev);
231 if (IS_ERR(info->role_sw))
232 return dev_err_probe(dev, PTR_ERR(info->role_sw),
233 "failed to get role switch\n");
234
235 ret = usb_conn_psy_register(info);
236 if (ret)
237 goto put_role_sw;
238
239 if (info->id_gpiod) {
240 info->id_irq = gpiod_to_irq(info->id_gpiod);
241 if (info->id_irq < 0) {
242 dev_err(dev, "failed to get ID IRQ\n");
243 ret = info->id_irq;
244 goto put_role_sw;
245 }
246
247 ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
248 usb_conn_isr, USB_CONN_IRQF,
249 pdev->name, info);
250 if (ret < 0) {
251 dev_err(dev, "failed to request ID IRQ\n");
252 goto put_role_sw;
253 }
254 }
255
256 if (info->vbus_gpiod) {
257 info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
258 if (info->vbus_irq < 0) {
259 dev_err(dev, "failed to get VBUS IRQ\n");
260 ret = info->vbus_irq;
261 goto put_role_sw;
262 }
263
264 ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
265 usb_conn_isr, USB_CONN_IRQF,
266 pdev->name, info);
267 if (ret < 0) {
268 dev_err(dev, "failed to request VBUS IRQ\n");
269 goto put_role_sw;
270 }
271 }
272
273 platform_set_drvdata(pdev, info);
274
275 /* Perform initial detection */
276 usb_conn_queue_dwork(info, 0);
277
278 return 0;
279
280put_role_sw:
281 usb_role_switch_put(info->role_sw);
282 return ret;
283}
284
285static int usb_conn_remove(struct platform_device *pdev)
286{
287 struct usb_conn_info *info = platform_get_drvdata(pdev);
288
289 cancel_delayed_work_sync(&info->dw_det);
290
291 if (info->last_role == USB_ROLE_HOST && info->vbus)
292 regulator_disable(info->vbus);
293
294 usb_role_switch_put(info->role_sw);
295
296 return 0;
297}
298
299static int __maybe_unused usb_conn_suspend(struct device *dev)
300{
301 struct usb_conn_info *info = dev_get_drvdata(dev);
302
303 if (info->id_gpiod)
304 disable_irq(info->id_irq);
305 if (info->vbus_gpiod)
306 disable_irq(info->vbus_irq);
307
308 pinctrl_pm_select_sleep_state(dev);
309
310 return 0;
311}
312
313static int __maybe_unused usb_conn_resume(struct device *dev)
314{
315 struct usb_conn_info *info = dev_get_drvdata(dev);
316
317 pinctrl_pm_select_default_state(dev);
318
319 if (info->id_gpiod)
320 enable_irq(info->id_irq);
321 if (info->vbus_gpiod)
322 enable_irq(info->vbus_irq);
323
324 usb_conn_queue_dwork(info, 0);
325
326 return 0;
327}
328
329static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
330 usb_conn_suspend, usb_conn_resume);
331
332static const struct of_device_id usb_conn_dt_match[] = {
333 { .compatible = "gpio-usb-b-connector", },
334 { }
335};
336MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
337
338static struct platform_driver usb_conn_driver = {
339 .probe = usb_conn_probe,
340 .remove = usb_conn_remove,
341 .driver = {
342 .name = "usb-conn-gpio",
343 .pm = &usb_conn_pm_ops,
344 .of_match_table = usb_conn_dt_match,
345 },
346};
347
348module_platform_driver(usb_conn_driver);
349
350MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
351MODULE_DESCRIPTION("USB GPIO based connection detection driver");
352MODULE_LICENSE("GPL v2");