1/*
  2 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
  3 *
  4 * Copyright (C) 2008 Google, Inc.
  5 * Author: Mike Lockwood <lockwood@android.com>
  6 *
  7 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
  8 * (originally switch class is supported)
  9 *
 10 * This software is licensed under the terms of the GNU General Public
 11 * License version 2, as published by the Free Software Foundation, and
 12 * may be copied, distributed, and modified under those terms.
 13 *
 14 * This program is distributed in the hope that it will be useful,
 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 17 * GNU General Public License for more details.
 18 */
 19
 20#include <linux/extcon.h>
 21#include <linux/extcon/extcon-gpio.h>
 22#include <linux/gpio.h>
 23#include <linux/gpio/consumer.h>
 24#include <linux/init.h>
 25#include <linux/interrupt.h>
 26#include <linux/kernel.h>
 27#include <linux/module.h>
 28#include <linux/platform_device.h>
 29#include <linux/slab.h>
 30#include <linux/workqueue.h>
 31
 32struct gpio_extcon_data {
 33	struct extcon_dev *edev;
 34	int irq;
 35	struct delayed_work work;
 36	unsigned long debounce_jiffies;
 37
 38	struct gpio_desc *id_gpiod;
 39	struct gpio_extcon_pdata *pdata;
 40};
 41
 42static void gpio_extcon_work(struct work_struct *work)
 43{
 44	int state;
 45	struct gpio_extcon_data	*data =
 46		container_of(to_delayed_work(work), struct gpio_extcon_data,
 47			     work);
 48
 49	state = gpiod_get_value_cansleep(data->id_gpiod);
 50	if (data->pdata->gpio_active_low)
 51		state = !state;
 52	extcon_set_state(data->edev, 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_init(struct device *dev, struct gpio_extcon_data *data)
 65{
 66	struct gpio_extcon_pdata *pdata = data->pdata;
 67	int ret;
 68
 69	ret = devm_gpio_request_one(dev, pdata->gpio, GPIOF_DIR_IN,
 70				dev_name(dev));
 71	if (ret < 0)
 72		return ret;
 73
 74	data->id_gpiod = gpio_to_desc(pdata->gpio);
 75	if (!data->id_gpiod)
 76		return -EINVAL;
 77
 78	if (pdata->debounce) {
 79		ret = gpiod_set_debounce(data->id_gpiod,
 80					pdata->debounce * 1000);
 81		if (ret < 0)
 82			data->debounce_jiffies =
 83				msecs_to_jiffies(pdata->debounce);
 84	}
 85
 86	data->irq = gpiod_to_irq(data->id_gpiod);
 87	if (data->irq < 0)
 88		return data->irq;
 89
 90	return 0;
 91}
 92
 93static int gpio_extcon_probe(struct platform_device *pdev)
 94{
 95	struct gpio_extcon_pdata *pdata = dev_get_platdata(&pdev->dev);
 96	struct gpio_extcon_data *data;
 97	int ret;
 98
 99	if (!pdata)
100		return -EBUSY;
101	if (!pdata->irq_flags || pdata->extcon_id > EXTCON_NONE)
102		return -EINVAL;
103
104	data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
105				   GFP_KERNEL);
106	if (!data)
107		return -ENOMEM;
108	data->pdata = pdata;
109
110	/* Initialize the gpio */
111	ret = gpio_extcon_init(&pdev->dev, data);
112	if (ret < 0)
113		return ret;
114
115	/* Allocate the memory of extcon devie and register extcon device */
116	data->edev = devm_extcon_dev_allocate(&pdev->dev, &pdata->extcon_id);
117	if (IS_ERR(data->edev)) {
118		dev_err(&pdev->dev, "failed to allocate extcon device\n");
119		return -ENOMEM;
120	}
121
122	ret = devm_extcon_dev_register(&pdev->dev, data->edev);
123	if (ret < 0)
124		return ret;
125
126	INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
127
128	/*
129	 * Request the interrupt of gpio to detect whether external connector
130	 * is attached or detached.
131	 */
132	ret = devm_request_any_context_irq(&pdev->dev, data->irq,
133					gpio_irq_handler, pdata->irq_flags,
134					pdev->name, data);
135	if (ret < 0)
136		return ret;
137
138	platform_set_drvdata(pdev, data);
139	/* Perform initial detection */
140	gpio_extcon_work(&data->work.work);
141
142	return 0;
143}
144
145static int gpio_extcon_remove(struct platform_device *pdev)
146{
147	struct gpio_extcon_data *data = platform_get_drvdata(pdev);
148
149	cancel_delayed_work_sync(&data->work);
150
151	return 0;
152}
153
154#ifdef CONFIG_PM_SLEEP
155static int gpio_extcon_resume(struct device *dev)
156{
157	struct gpio_extcon_data *data;
158
159	data = dev_get_drvdata(dev);
160	if (data->pdata->check_on_resume)
161		queue_delayed_work(system_power_efficient_wq,
162			&data->work, data->debounce_jiffies);
163
164	return 0;
165}
166#endif
167
168static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
169
170static struct platform_driver gpio_extcon_driver = {
171	.probe		= gpio_extcon_probe,
172	.remove		= gpio_extcon_remove,
173	.driver		= {
174		.name	= "extcon-gpio",
175		.pm	= &gpio_extcon_pm_ops,
176	},
177};
178
179module_platform_driver(gpio_extcon_driver);
180
181MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
182MODULE_DESCRIPTION("GPIO extcon driver");
183MODULE_LICENSE("GPL");