1 // SPDX-License-Identifier: GPL-2.0-only
3 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
5 * Copyright (C) 2008 Google, Inc.
6 * Author: Mike Lockwood <lockwood@android.com>
8 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
9 * (originally switch class is supported)
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>
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
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.
34 struct 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;
44 static void gpio_extcon_work(struct work_struct *work)
47 struct gpio_extcon_data *data =
48 container_of(to_delayed_work(work), struct gpio_extcon_data,
51 state = gpiod_get_value_cansleep(data->gpiod);
52 extcon_set_state_sync(data->edev, data->extcon_id, state);
55 static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
57 struct gpio_extcon_data *data = dev_id;
59 queue_delayed_work(system_power_efficient_wq, &data->work,
60 data->debounce_jiffies);
64 static int gpio_extcon_probe(struct platform_device *pdev)
66 struct gpio_extcon_data *data;
67 struct device *dev = &pdev->dev;
68 unsigned long irq_flags;
72 data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
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.
83 if (data->extcon_id > EXTCON_NONE)
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);
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
99 if (gpiod_is_active_low(data->gpiod))
100 irq_flags = IRQF_TRIGGER_FALLING;
102 irq_flags = IRQF_TRIGGER_RISING;
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");
111 ret = devm_extcon_dev_register(dev, data->edev);
115 INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
118 * Request the interrupt of gpio to detect whether external connector
119 * is attached or detached.
121 ret = devm_request_any_context_irq(dev, irq,
122 gpio_irq_handler, irq_flags,
127 platform_set_drvdata(pdev, data);
128 /* Perform initial detection */
129 gpio_extcon_work(&data->work.work);
134 static int gpio_extcon_remove(struct platform_device *pdev)
136 struct gpio_extcon_data *data = platform_get_drvdata(pdev);
138 cancel_delayed_work_sync(&data->work);
143 #ifdef CONFIG_PM_SLEEP
144 static int gpio_extcon_resume(struct device *dev)
146 struct gpio_extcon_data *data;
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);
157 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
159 static struct platform_driver gpio_extcon_driver = {
160 .probe = gpio_extcon_probe,
161 .remove = gpio_extcon_remove,
163 .name = "extcon-gpio",
164 .pm = &gpio_extcon_pm_ops,
168 module_platform_driver(gpio_extcon_driver);
170 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
171 MODULE_DESCRIPTION("GPIO extcon driver");
172 MODULE_LICENSE("GPL");