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 bool check_on_resume; 44 }; 45 46 static void gpio_extcon_work(struct work_struct *work) 47 { 48 int state; 49 struct gpio_extcon_data *data = 50 container_of(to_delayed_work(work), struct gpio_extcon_data, 51 work); 52 53 state = gpio_get_value(data->gpio); 54 if (data->gpio_active_low) 55 state = !state; 56 extcon_set_state(&data->edev, state); 57 } 58 59 static irqreturn_t gpio_irq_handler(int irq, void *dev_id) 60 { 61 struct gpio_extcon_data *extcon_data = dev_id; 62 63 queue_delayed_work(system_power_efficient_wq, &extcon_data->work, 64 extcon_data->debounce_jiffies); 65 return IRQ_HANDLED; 66 } 67 68 static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf) 69 { 70 struct gpio_extcon_data *extcon_data = 71 container_of(edev, struct gpio_extcon_data, edev); 72 const char *state; 73 if (extcon_get_state(edev)) 74 state = extcon_data->state_on; 75 else 76 state = extcon_data->state_off; 77 78 if (state) 79 return sprintf(buf, "%s\n", state); 80 return -EINVAL; 81 } 82 83 static int gpio_extcon_probe(struct platform_device *pdev) 84 { 85 struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev); 86 struct gpio_extcon_data *extcon_data; 87 int ret; 88 89 if (!pdata) 90 return -EBUSY; 91 if (!pdata->irq_flags) { 92 dev_err(&pdev->dev, "IRQ flag is not specified.\n"); 93 return -EINVAL; 94 } 95 96 extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data), 97 GFP_KERNEL); 98 if (!extcon_data) 99 return -ENOMEM; 100 101 extcon_data->edev.name = pdata->name; 102 extcon_data->edev.dev.parent = &pdev->dev; 103 extcon_data->gpio = pdata->gpio; 104 extcon_data->gpio_active_low = pdata->gpio_active_low; 105 extcon_data->state_on = pdata->state_on; 106 extcon_data->state_off = pdata->state_off; 107 extcon_data->check_on_resume = pdata->check_on_resume; 108 if (pdata->state_on && pdata->state_off) 109 extcon_data->edev.print_state = extcon_gpio_print_state; 110 111 ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN, 112 pdev->name); 113 if (ret < 0) 114 return ret; 115 116 if (pdata->debounce) { 117 ret = gpio_set_debounce(extcon_data->gpio, 118 pdata->debounce * 1000); 119 if (ret < 0) 120 extcon_data->debounce_jiffies = 121 msecs_to_jiffies(pdata->debounce); 122 } 123 124 ret = extcon_dev_register(&extcon_data->edev); 125 if (ret < 0) 126 return ret; 127 128 INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); 129 130 extcon_data->irq = gpio_to_irq(extcon_data->gpio); 131 if (extcon_data->irq < 0) { 132 ret = extcon_data->irq; 133 goto err; 134 } 135 136 ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, 137 pdata->irq_flags, pdev->name, 138 extcon_data); 139 if (ret < 0) 140 goto err; 141 142 platform_set_drvdata(pdev, extcon_data); 143 /* Perform initial detection */ 144 gpio_extcon_work(&extcon_data->work.work); 145 146 return 0; 147 148 err: 149 extcon_dev_unregister(&extcon_data->edev); 150 151 return ret; 152 } 153 154 static int gpio_extcon_remove(struct platform_device *pdev) 155 { 156 struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); 157 158 cancel_delayed_work_sync(&extcon_data->work); 159 free_irq(extcon_data->irq, extcon_data); 160 extcon_dev_unregister(&extcon_data->edev); 161 162 return 0; 163 } 164 165 #ifdef CONFIG_PM_SLEEP 166 static int gpio_extcon_resume(struct device *dev) 167 { 168 struct gpio_extcon_data *extcon_data; 169 170 extcon_data = dev_get_drvdata(dev); 171 if (extcon_data->check_on_resume) 172 queue_delayed_work(system_power_efficient_wq, 173 &extcon_data->work, extcon_data->debounce_jiffies); 174 175 return 0; 176 } 177 #endif 178 179 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); 180 181 static struct platform_driver gpio_extcon_driver = { 182 .probe = gpio_extcon_probe, 183 .remove = gpio_extcon_remove, 184 .driver = { 185 .name = "extcon-gpio", 186 .owner = THIS_MODULE, 187 .pm = &gpio_extcon_pm_ops, 188 }, 189 }; 190 191 module_platform_driver(gpio_extcon_driver); 192 193 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); 194 MODULE_DESCRIPTION("GPIO extcon driver"); 195 MODULE_LICENSE("GPL"); 196