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/workqueue.h> 30 #include <linux/gpio.h> 31 #include <linux/extcon.h> 32 #include <linux/extcon/extcon-gpio.h> 33 34 struct gpio_extcon_data { 35 struct extcon_dev edev; 36 unsigned gpio; 37 bool gpio_active_low; 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 if (data->gpio_active_low) 54 state = !state; 55 extcon_set_state(&data->edev, state); 56 } 57 58 static irqreturn_t gpio_irq_handler(int irq, void *dev_id) 59 { 60 struct gpio_extcon_data *extcon_data = dev_id; 61 62 queue_delayed_work(system_power_efficient_wq, &extcon_data->work, 63 extcon_data->debounce_jiffies); 64 return IRQ_HANDLED; 65 } 66 67 static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf) 68 { 69 struct gpio_extcon_data *extcon_data = 70 container_of(edev, struct gpio_extcon_data, edev); 71 const char *state; 72 if (extcon_get_state(edev)) 73 state = extcon_data->state_on; 74 else 75 state = extcon_data->state_off; 76 77 if (state) 78 return sprintf(buf, "%s\n", state); 79 return -EINVAL; 80 } 81 82 static int gpio_extcon_probe(struct platform_device *pdev) 83 { 84 struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev); 85 struct gpio_extcon_data *extcon_data; 86 int ret; 87 88 if (!pdata) 89 return -EBUSY; 90 if (!pdata->irq_flags) { 91 dev_err(&pdev->dev, "IRQ flag is not specified.\n"); 92 return -EINVAL; 93 } 94 95 extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data), 96 GFP_KERNEL); 97 if (!extcon_data) 98 return -ENOMEM; 99 100 extcon_data->edev.name = pdata->name; 101 extcon_data->edev.dev.parent = &pdev->dev; 102 extcon_data->gpio = pdata->gpio; 103 extcon_data->gpio_active_low = pdata->gpio_active_low; 104 extcon_data->state_on = pdata->state_on; 105 extcon_data->state_off = pdata->state_off; 106 if (pdata->state_on && pdata->state_off) 107 extcon_data->edev.print_state = extcon_gpio_print_state; 108 if (pdata->debounce) { 109 ret = gpio_set_debounce(extcon_data->gpio, 110 pdata->debounce * 1000); 111 if (ret < 0) 112 extcon_data->debounce_jiffies = 113 msecs_to_jiffies(pdata->debounce); 114 } 115 116 ret = extcon_dev_register(&extcon_data->edev); 117 if (ret < 0) 118 return ret; 119 120 ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN, 121 pdev->name); 122 if (ret < 0) 123 goto err; 124 125 INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); 126 127 extcon_data->irq = gpio_to_irq(extcon_data->gpio); 128 if (extcon_data->irq < 0) { 129 ret = extcon_data->irq; 130 goto err; 131 } 132 133 ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, 134 pdata->irq_flags, pdev->name, 135 extcon_data); 136 if (ret < 0) 137 goto err; 138 139 platform_set_drvdata(pdev, extcon_data); 140 /* Perform initial detection */ 141 gpio_extcon_work(&extcon_data->work.work); 142 143 return 0; 144 145 err: 146 extcon_dev_unregister(&extcon_data->edev); 147 148 return ret; 149 } 150 151 static int gpio_extcon_remove(struct platform_device *pdev) 152 { 153 struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); 154 155 cancel_delayed_work_sync(&extcon_data->work); 156 free_irq(extcon_data->irq, extcon_data); 157 extcon_dev_unregister(&extcon_data->edev); 158 159 return 0; 160 } 161 162 static struct platform_driver gpio_extcon_driver = { 163 .probe = gpio_extcon_probe, 164 .remove = gpio_extcon_remove, 165 .driver = { 166 .name = "extcon-gpio", 167 .owner = THIS_MODULE, 168 }, 169 }; 170 171 module_platform_driver(gpio_extcon_driver); 172 173 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); 174 MODULE_DESCRIPTION("GPIO extcon driver"); 175 MODULE_LICENSE("GPL"); 176