1/**
2 * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver
3 *
4 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
5 * Author: Roger Quadros <rogerq@ti.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/extcon.h>
18#include <linux/init.h>
19#include <linux/interrupt.h>
20#include <linux/irq.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/of_gpio.h>
24#include <linux/platform_device.h>
25#include <linux/slab.h>
26#include <linux/workqueue.h>
27
28#define USB_GPIO_DEBOUNCE_MS	20	/* ms */
29
30struct usb_extcon_info {
31	struct device *dev;
32	struct extcon_dev *edev;
33
34	struct gpio_desc *id_gpiod;
35	int id_irq;
36
37	unsigned long debounce_jiffies;
38	struct delayed_work wq_detcable;
39};
40
41/* List of detectable cables */
42enum {
43	EXTCON_CABLE_USB = 0,
44	EXTCON_CABLE_USB_HOST,
45
46	EXTCON_CABLE_END,
47};
48
49static const char *usb_extcon_cable[] = {
50	[EXTCON_CABLE_USB] = "USB",
51	[EXTCON_CABLE_USB_HOST] = "USB-HOST",
52	NULL,
53};
54
55static void usb_extcon_detect_cable(struct work_struct *work)
56{
57	int id;
58	struct usb_extcon_info *info = container_of(to_delayed_work(work),
59						    struct usb_extcon_info,
60						    wq_detcable);
61
62	/* check ID and update cable state */
63	id = gpiod_get_value_cansleep(info->id_gpiod);
64	if (id) {
65		/*
66		 * ID = 1 means USB HOST cable detached.
67		 * As we don't have event for USB peripheral cable attached,
68		 * we simulate USB peripheral attach here.
69		 */
70		extcon_set_cable_state(info->edev,
71				       usb_extcon_cable[EXTCON_CABLE_USB_HOST],
72				       false);
73		extcon_set_cable_state(info->edev,
74				       usb_extcon_cable[EXTCON_CABLE_USB],
75				       true);
76	} else {
77		/*
78		 * ID = 0 means USB HOST cable attached.
79		 * As we don't have event for USB peripheral cable detached,
80		 * we simulate USB peripheral detach here.
81		 */
82		extcon_set_cable_state(info->edev,
83				       usb_extcon_cable[EXTCON_CABLE_USB],
84				       false);
85		extcon_set_cable_state(info->edev,
86				       usb_extcon_cable[EXTCON_CABLE_USB_HOST],
87				       true);
88	}
89}
90
91static irqreturn_t usb_irq_handler(int irq, void *dev_id)
92{
93	struct usb_extcon_info *info = dev_id;
94
95	queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
96			   info->debounce_jiffies);
97
98	return IRQ_HANDLED;
99}
100
101static int usb_extcon_probe(struct platform_device *pdev)
102{
103	struct device *dev = &pdev->dev;
104	struct device_node *np = dev->of_node;
105	struct usb_extcon_info *info;
106	int ret;
107
108	if (!np)
109		return -EINVAL;
110
111	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
112	if (!info)
113		return -ENOMEM;
114
115	info->dev = dev;
116	info->id_gpiod = devm_gpiod_get(&pdev->dev, "id");
117	if (IS_ERR(info->id_gpiod)) {
118		dev_err(dev, "failed to get ID GPIO\n");
119		return PTR_ERR(info->id_gpiod);
120	}
121
122	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
123	if (IS_ERR(info->edev)) {
124		dev_err(dev, "failed to allocate extcon device\n");
125		return -ENOMEM;
126	}
127
128	ret = devm_extcon_dev_register(dev, info->edev);
129	if (ret < 0) {
130		dev_err(dev, "failed to register extcon device\n");
131		return ret;
132	}
133
134	ret = gpiod_set_debounce(info->id_gpiod,
135				 USB_GPIO_DEBOUNCE_MS * 1000);
136	if (ret < 0)
137		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);
138
139	INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);
140
141	info->id_irq = gpiod_to_irq(info->id_gpiod);
142	if (info->id_irq < 0) {
143		dev_err(dev, "failed to get ID IRQ\n");
144		return info->id_irq;
145	}
146
147	ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
148					usb_irq_handler,
149					IRQF_TRIGGER_RISING |
150					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
151					pdev->name, info);
152	if (ret < 0) {
153		dev_err(dev, "failed to request handler for ID IRQ\n");
154		return ret;
155	}
156
157	platform_set_drvdata(pdev, info);
158	device_init_wakeup(dev, 1);
159
160	/* Perform initial detection */
161	usb_extcon_detect_cable(&info->wq_detcable.work);
162
163	return 0;
164}
165
166static int usb_extcon_remove(struct platform_device *pdev)
167{
168	struct usb_extcon_info *info = platform_get_drvdata(pdev);
169
170	cancel_delayed_work_sync(&info->wq_detcable);
171
172	return 0;
173}
174
175#ifdef CONFIG_PM_SLEEP
176static int usb_extcon_suspend(struct device *dev)
177{
178	struct usb_extcon_info *info = dev_get_drvdata(dev);
179	int ret = 0;
180
181	if (device_may_wakeup(dev)) {
182		ret = enable_irq_wake(info->id_irq);
183		if (ret)
184			return ret;
185	}
186
187	/*
188	 * We don't want to process any IRQs after this point
189	 * as GPIOs used behind I2C subsystem might not be
190	 * accessible until resume completes. So disable IRQ.
191	 */
192	disable_irq(info->id_irq);
193
194	return ret;
195}
196
197static int usb_extcon_resume(struct device *dev)
198{
199	struct usb_extcon_info *info = dev_get_drvdata(dev);
200	int ret = 0;
201
202	if (device_may_wakeup(dev)) {
203		ret = disable_irq_wake(info->id_irq);
204		if (ret)
205			return ret;
206	}
207
208	enable_irq(info->id_irq);
209
210	return ret;
211}
212#endif
213
214static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops,
215			 usb_extcon_suspend, usb_extcon_resume);
216
217static const struct of_device_id usb_extcon_dt_match[] = {
218	{ .compatible = "linux,extcon-usb-gpio", },
219	{ /* sentinel */ }
220};
221MODULE_DEVICE_TABLE(of, usb_extcon_dt_match);
222
223static struct platform_driver usb_extcon_driver = {
224	.probe		= usb_extcon_probe,
225	.remove		= usb_extcon_remove,
226	.driver		= {
227		.name	= "extcon-usb-gpio",
228		.pm	= &usb_extcon_pm_ops,
229		.of_match_table = usb_extcon_dt_match,
230	},
231};
232
233module_platform_driver(usb_extcon_driver);
234
235MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
236MODULE_DESCRIPTION("USB GPIO extcon driver");
237MODULE_LICENSE("GPL v2");
238