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 35 struct 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 45 static 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 56 static 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 65 static 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 80 static 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 return ret; 109 110 ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN, 111 pdev->name); 112 if (ret < 0) 113 goto err; 114 115 INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); 116 117 extcon_data->irq = gpio_to_irq(extcon_data->gpio); 118 if (extcon_data->irq < 0) { 119 ret = extcon_data->irq; 120 goto err; 121 } 122 123 ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, 124 pdata->irq_flags, pdev->name, 125 extcon_data); 126 if (ret < 0) 127 goto err; 128 129 platform_set_drvdata(pdev, extcon_data); 130 /* Perform initial detection */ 131 gpio_extcon_work(&extcon_data->work.work); 132 133 return 0; 134 135 err: 136 extcon_dev_unregister(&extcon_data->edev); 137 138 return ret; 139 } 140 141 static int __devexit gpio_extcon_remove(struct platform_device *pdev) 142 { 143 struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); 144 145 cancel_delayed_work_sync(&extcon_data->work); 146 free_irq(extcon_data->irq, extcon_data); 147 extcon_dev_unregister(&extcon_data->edev); 148 149 return 0; 150 } 151 152 static struct platform_driver gpio_extcon_driver = { 153 .probe = gpio_extcon_probe, 154 .remove = __devexit_p(gpio_extcon_remove), 155 .driver = { 156 .name = "extcon-gpio", 157 .owner = THIS_MODULE, 158 }, 159 }; 160 161 module_platform_driver(gpio_extcon_driver); 162 163 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); 164 MODULE_DESCRIPTION("GPIO extcon driver"); 165 MODULE_LICENSE("GPL"); 166