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/extcon.h> 24 #include <linux/extcon/extcon-gpio.h> 25 #include <linux/gpio.h> 26 #include <linux/init.h> 27 #include <linux/interrupt.h> 28 #include <linux/kernel.h> 29 #include <linux/module.h> 30 #include <linux/platform_device.h> 31 #include <linux/slab.h> 32 #include <linux/workqueue.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 int gpio_extcon_probe(struct platform_device *pdev) 69 { 70 struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev); 71 struct gpio_extcon_data *extcon_data; 72 int ret; 73 74 if (!pdata) 75 return -EBUSY; 76 if (!pdata->irq_flags) { 77 dev_err(&pdev->dev, "IRQ flag is not specified.\n"); 78 return -EINVAL; 79 } 80 81 extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data), 82 GFP_KERNEL); 83 if (!extcon_data) 84 return -ENOMEM; 85 86 extcon_data->edev = devm_extcon_dev_allocate(&pdev->dev, NULL); 87 if (IS_ERR(extcon_data->edev)) { 88 dev_err(&pdev->dev, "failed to allocate extcon device\n"); 89 return -ENOMEM; 90 } 91 92 extcon_data->gpio = pdata->gpio; 93 extcon_data->gpio_active_low = pdata->gpio_active_low; 94 extcon_data->state_on = pdata->state_on; 95 extcon_data->state_off = pdata->state_off; 96 extcon_data->check_on_resume = pdata->check_on_resume; 97 98 ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN, 99 pdev->name); 100 if (ret < 0) 101 return ret; 102 103 if (pdata->debounce) { 104 ret = gpio_set_debounce(extcon_data->gpio, 105 pdata->debounce * 1000); 106 if (ret < 0) 107 extcon_data->debounce_jiffies = 108 msecs_to_jiffies(pdata->debounce); 109 } 110 111 ret = devm_extcon_dev_register(&pdev->dev, extcon_data->edev); 112 if (ret < 0) 113 return ret; 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 return extcon_data->irq; 120 121 ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, 122 pdata->irq_flags, pdev->name, 123 extcon_data); 124 if (ret < 0) 125 return ret; 126 127 platform_set_drvdata(pdev, extcon_data); 128 /* Perform initial detection */ 129 gpio_extcon_work(&extcon_data->work.work); 130 131 return 0; 132 } 133 134 static int gpio_extcon_remove(struct platform_device *pdev) 135 { 136 struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); 137 138 cancel_delayed_work_sync(&extcon_data->work); 139 free_irq(extcon_data->irq, extcon_data); 140 141 return 0; 142 } 143 144 #ifdef CONFIG_PM_SLEEP 145 static int gpio_extcon_resume(struct device *dev) 146 { 147 struct gpio_extcon_data *extcon_data; 148 149 extcon_data = dev_get_drvdata(dev); 150 if (extcon_data->check_on_resume) 151 queue_delayed_work(system_power_efficient_wq, 152 &extcon_data->work, extcon_data->debounce_jiffies); 153 154 return 0; 155 } 156 #endif 157 158 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); 159 160 static struct platform_driver gpio_extcon_driver = { 161 .probe = gpio_extcon_probe, 162 .remove = gpio_extcon_remove, 163 .driver = { 164 .name = "extcon-gpio", 165 .pm = &gpio_extcon_pm_ops, 166 }, 167 }; 168 169 module_platform_driver(gpio_extcon_driver); 170 171 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); 172 MODULE_DESCRIPTION("GPIO extcon driver"); 173 MODULE_LICENSE("GPL"); 174