1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
4 *
5 * Copyright (C) 2008 Google, Inc.
6 * Author: Mike Lockwood <lockwood@android.com>
7 *
8 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
9 * (originally switch class is supported)
10 */
11
12#include <linux/extcon-provider.h>
13#include <linux/gpio/consumer.h>
14#include <linux/init.h>
15#include <linux/interrupt.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/platform_device.h>
19#include <linux/slab.h>
20#include <linux/workqueue.h>
21
22/**
23 * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.
24 * @edev:		Extcon device.
25 * @work:		Work fired by the interrupt.
26 * @debounce_jiffies:	Number of jiffies to wait for the GPIO to stabilize, from the debounce
27 *			value.
28 * @gpiod:		GPIO descriptor for this external connector.
29 * @extcon_id:		The unique id of specific external connector.
30 * @debounce:		Debounce time for GPIO IRQ in ms.
31 * @check_on_resume:	Boolean describing whether to check the state of gpio
32 *			while resuming from sleep.
33 */
34struct gpio_extcon_data {
35	struct extcon_dev *edev;
36	struct delayed_work work;
37	unsigned long debounce_jiffies;
38	struct gpio_desc *gpiod;
39	unsigned int extcon_id;
40	unsigned long debounce;
41	bool check_on_resume;
42};
43
44static void gpio_extcon_work(struct work_struct *work)
45{
46	int state;
47	struct gpio_extcon_data	*data =
48		container_of(to_delayed_work(work), struct gpio_extcon_data,
49			     work);
50
51	state = gpiod_get_value_cansleep(data->gpiod);
52	extcon_set_state_sync(data->edev, data->extcon_id, state);
53}
54
55static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
56{
57	struct gpio_extcon_data *data = dev_id;
58
59	queue_delayed_work(system_power_efficient_wq, &data->work,
60			      data->debounce_jiffies);
61	return IRQ_HANDLED;
62}
63
64static int gpio_extcon_probe(struct platform_device *pdev)
65{
66	struct gpio_extcon_data *data;
67	struct device *dev = &pdev->dev;
68	unsigned long irq_flags;
69	int irq;
70	int ret;
71
72	data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
73	if (!data)
74		return -ENOMEM;
75
76	/*
77	 * FIXME: extcon_id represents the unique identifier of external
78	 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id
79	 * is necessary to register the extcon device. But, it's not yet
80	 * developed to get the extcon id from device-tree or others.
81	 * On later, it have to be solved.
82	 */
83	if (data->extcon_id > EXTCON_NONE)
84		return -EINVAL;
85
86	data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
87	if (IS_ERR(data->gpiod))
88		return PTR_ERR(data->gpiod);
89	irq = gpiod_to_irq(data->gpiod);
90	if (irq <= 0)
91		return irq;
92
93	/*
94	 * It is unlikely that this is an acknowledged interrupt that goes
95	 * away after handling, what we are looking for are falling edges
96	 * if the signal is active low, and rising edges if the signal is
97	 * active high.
98	 */
99	if (gpiod_is_active_low(data->gpiod))
100		irq_flags = IRQF_TRIGGER_FALLING;
101	else
102		irq_flags = IRQF_TRIGGER_RISING;
103
104	/* Allocate the memory of extcon devie and register extcon device */
105	data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);
106	if (IS_ERR(data->edev)) {
107		dev_err(dev, "failed to allocate extcon device\n");
108		return -ENOMEM;
109	}
110
111	ret = devm_extcon_dev_register(dev, data->edev);
112	if (ret < 0)
113		return ret;
114
115	INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
116
117	/*
118	 * Request the interrupt of gpio to detect whether external connector
119	 * is attached or detached.
120	 */
121	ret = devm_request_any_context_irq(dev, irq,
122					gpio_irq_handler, irq_flags,
123					pdev->name, data);
124	if (ret < 0)
125		return ret;
126
127	platform_set_drvdata(pdev, data);
128	/* Perform initial detection */
129	gpio_extcon_work(&data->work.work);
130
131	return 0;
132}
133
134static int gpio_extcon_remove(struct platform_device *pdev)
135{
136	struct gpio_extcon_data *data = platform_get_drvdata(pdev);
137
138	cancel_delayed_work_sync(&data->work);
139
140	return 0;
141}
142
143#ifdef CONFIG_PM_SLEEP
144static int gpio_extcon_resume(struct device *dev)
145{
146	struct gpio_extcon_data *data;
147
148	data = dev_get_drvdata(dev);
149	if (data->check_on_resume)
150		queue_delayed_work(system_power_efficient_wq,
151			&data->work, data->debounce_jiffies);
152
153	return 0;
154}
155#endif
156
157static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
158
159static struct platform_driver gpio_extcon_driver = {
160	.probe		= gpio_extcon_probe,
161	.remove		= gpio_extcon_remove,
162	.driver		= {
163		.name	= "extcon-gpio",
164		.pm	= &gpio_extcon_pm_ops,
165	},
166};
167
168module_platform_driver(gpio_extcon_driver);
169
170MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
171MODULE_DESCRIPTION("GPIO extcon driver");
172MODULE_LICENSE("GPL");
173