1/*
  2 *  drivers/extcon/extcon_gpio.c
  3 *
  4 *  Single-state GPIO extcon driver based on extcon class
  5 *
  6 * Copyright (C) 2008 Google, Inc.
  7 * Author: Mike Lockwood <lockwood@android.com>
  8 *
  9 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
 10 * (originally switch class is supported)
 11 *
 12 * This software is licensed under the terms of the GNU General Public
 13 * License version 2, as published by the Free Software Foundation, and
 14 * may be copied, distributed, and modified under those terms.
 15 *
 16 * This program is distributed in the hope that it will be useful,
 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 19 * GNU General Public License for more details.
 20 *
 21*/
 22
 23#include <linux/module.h>
 24#include <linux/kernel.h>
 25#include <linux/init.h>
 26#include <linux/interrupt.h>
 27#include <linux/platform_device.h>
 28#include <linux/slab.h>
 29#include <linux/extcon.h>
 30#include <linux/workqueue.h>
 31#include <linux/gpio.h>
 32#include <linux/extcon.h>
 33#include <linux/extcon/extcon_gpio.h>
 34
 35struct gpio_extcon_data {
 36	struct extcon_dev edev;
 37	unsigned gpio;
 38	const char *state_on;
 39	const char *state_off;
 40	int irq;
 41	struct delayed_work work;
 42	unsigned long debounce_jiffies;
 43};
 44
 45static void gpio_extcon_work(struct work_struct *work)
 46{
 47	int state;
 48	struct gpio_extcon_data	*data =
 49		container_of(to_delayed_work(work), struct gpio_extcon_data,
 50			     work);
 51
 52	state = gpio_get_value(data->gpio);
 53	extcon_set_state(&data->edev, state);
 54}
 55
 56static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
 57{
 58	struct gpio_extcon_data *extcon_data = dev_id;
 59
 60	schedule_delayed_work(&extcon_data->work,
 61			      extcon_data->debounce_jiffies);
 62	return IRQ_HANDLED;
 63}
 64
 65static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf)
 66{
 67	struct gpio_extcon_data	*extcon_data =
 68		container_of(edev, struct gpio_extcon_data, edev);
 69	const char *state;
 70	if (extcon_get_state(edev))
 71		state = extcon_data->state_on;
 72	else
 73		state = extcon_data->state_off;
 74
 75	if (state)
 76		return sprintf(buf, "%s\n", state);
 77	return -EINVAL;
 78}
 79
 80static int __devinit gpio_extcon_probe(struct platform_device *pdev)
 81{
 82	struct gpio_extcon_platform_data *pdata = pdev->dev.platform_data;
 83	struct gpio_extcon_data *extcon_data;
 84	int ret = 0;
 85
 86	if (!pdata)
 87		return -EBUSY;
 88	if (!pdata->irq_flags) {
 89		dev_err(&pdev->dev, "IRQ flag is not specified.\n");
 90		return -EINVAL;
 91	}
 92
 93	extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
 94				   GFP_KERNEL);
 95	if (!extcon_data)
 96		return -ENOMEM;
 97
 98	extcon_data->edev.name = pdata->name;
 99	extcon_data->gpio = pdata->gpio;
100	extcon_data->state_on = pdata->state_on;
101	extcon_data->state_off = pdata->state_off;
102	if (pdata->state_on && pdata->state_off)
103		extcon_data->edev.print_state = extcon_gpio_print_state;
104	extcon_data->debounce_jiffies = msecs_to_jiffies(pdata->debounce);
105
106	ret = extcon_dev_register(&extcon_data->edev, &pdev->dev);
107	if (ret < 0)
108		goto err_extcon_dev_register;
109
110	ret = gpio_request_one(extcon_data->gpio, GPIOF_DIR_IN, pdev->name);
111	if (ret < 0)
112		goto err_request_gpio;
113
114	INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
115
116	extcon_data->irq = gpio_to_irq(extcon_data->gpio);
117	if (extcon_data->irq < 0) {
118		ret = extcon_data->irq;
119		goto err_detect_irq_num_failed;
120	}
121
122	ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler,
123				      pdata->irq_flags, pdev->name,
124				      extcon_data);
125	if (ret < 0)
126		goto err_request_irq;
127
128	platform_set_drvdata(pdev, extcon_data);
129	/* Perform initial detection */
130	gpio_extcon_work(&extcon_data->work.work);
131
132	return 0;
133
134err_request_irq:
135err_detect_irq_num_failed:
136	gpio_free(extcon_data->gpio);
137err_request_gpio:
138	extcon_dev_unregister(&extcon_data->edev);
139err_extcon_dev_register:
140	devm_kfree(&pdev->dev, extcon_data);
141
142	return ret;
143}
144
145static int __devexit gpio_extcon_remove(struct platform_device *pdev)
146{
147	struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev);
148
149	cancel_delayed_work_sync(&extcon_data->work);
150	free_irq(extcon_data->irq, extcon_data);
151	gpio_free(extcon_data->gpio);
152	extcon_dev_unregister(&extcon_data->edev);
153	devm_kfree(&pdev->dev, extcon_data);
154
155	return 0;
156}
157
158static struct platform_driver gpio_extcon_driver = {
159	.probe		= gpio_extcon_probe,
160	.remove		= __devexit_p(gpio_extcon_remove),
161	.driver		= {
162		.name	= "extcon-gpio",
163		.owner	= THIS_MODULE,
164	},
165};
166
167module_platform_driver(gpio_extcon_driver);
168
169MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
170MODULE_DESCRIPTION("GPIO extcon driver");
171MODULE_LICENSE("GPL");