1 /** 2 * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver 3 * 4 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com 5 * Author: Roger Quadros <rogerq@ti.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/extcon.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/init.h> 20 #include <linux/interrupt.h> 21 #include <linux/irq.h> 22 #include <linux/kernel.h> 23 #include <linux/module.h> 24 #include <linux/of_gpio.h> 25 #include <linux/platform_device.h> 26 #include <linux/slab.h> 27 #include <linux/workqueue.h> 28 29 #define USB_GPIO_DEBOUNCE_MS 20 /* ms */ 30 31 struct usb_extcon_info { 32 struct device *dev; 33 struct extcon_dev *edev; 34 35 struct gpio_desc *id_gpiod; 36 int id_irq; 37 38 unsigned long debounce_jiffies; 39 struct delayed_work wq_detcable; 40 }; 41 42 static const unsigned int usb_extcon_cable[] = { 43 EXTCON_USB, 44 EXTCON_USB_HOST, 45 EXTCON_NONE, 46 }; 47 48 static void usb_extcon_detect_cable(struct work_struct *work) 49 { 50 int id; 51 struct usb_extcon_info *info = container_of(to_delayed_work(work), 52 struct usb_extcon_info, 53 wq_detcable); 54 55 /* check ID and update cable state */ 56 id = gpiod_get_value_cansleep(info->id_gpiod); 57 if (id) { 58 /* 59 * ID = 1 means USB HOST cable detached. 60 * As we don't have event for USB peripheral cable attached, 61 * we simulate USB peripheral attach here. 62 */ 63 extcon_set_cable_state_(info->edev, EXTCON_USB_HOST, false); 64 extcon_set_cable_state_(info->edev, EXTCON_USB, true); 65 } else { 66 /* 67 * ID = 0 means USB HOST cable attached. 68 * As we don't have event for USB peripheral cable detached, 69 * we simulate USB peripheral detach here. 70 */ 71 extcon_set_cable_state_(info->edev, EXTCON_USB, false); 72 extcon_set_cable_state_(info->edev, EXTCON_USB_HOST, true); 73 } 74 } 75 76 static irqreturn_t usb_irq_handler(int irq, void *dev_id) 77 { 78 struct usb_extcon_info *info = dev_id; 79 80 queue_delayed_work(system_power_efficient_wq, &info->wq_detcable, 81 info->debounce_jiffies); 82 83 return IRQ_HANDLED; 84 } 85 86 static int usb_extcon_probe(struct platform_device *pdev) 87 { 88 struct device *dev = &pdev->dev; 89 struct device_node *np = dev->of_node; 90 struct usb_extcon_info *info; 91 int ret; 92 93 if (!np) 94 return -EINVAL; 95 96 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); 97 if (!info) 98 return -ENOMEM; 99 100 info->dev = dev; 101 info->id_gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN); 102 if (IS_ERR(info->id_gpiod)) { 103 dev_err(dev, "failed to get ID GPIO\n"); 104 return PTR_ERR(info->id_gpiod); 105 } 106 107 info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable); 108 if (IS_ERR(info->edev)) { 109 dev_err(dev, "failed to allocate extcon device\n"); 110 return -ENOMEM; 111 } 112 113 ret = devm_extcon_dev_register(dev, info->edev); 114 if (ret < 0) { 115 dev_err(dev, "failed to register extcon device\n"); 116 return ret; 117 } 118 119 ret = gpiod_set_debounce(info->id_gpiod, 120 USB_GPIO_DEBOUNCE_MS * 1000); 121 if (ret < 0) 122 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS); 123 124 INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable); 125 126 info->id_irq = gpiod_to_irq(info->id_gpiod); 127 if (info->id_irq < 0) { 128 dev_err(dev, "failed to get ID IRQ\n"); 129 return info->id_irq; 130 } 131 132 ret = devm_request_threaded_irq(dev, info->id_irq, NULL, 133 usb_irq_handler, 134 IRQF_TRIGGER_RISING | 135 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 136 pdev->name, info); 137 if (ret < 0) { 138 dev_err(dev, "failed to request handler for ID IRQ\n"); 139 return ret; 140 } 141 142 platform_set_drvdata(pdev, info); 143 device_init_wakeup(dev, 1); 144 145 /* Perform initial detection */ 146 usb_extcon_detect_cable(&info->wq_detcable.work); 147 148 return 0; 149 } 150 151 static int usb_extcon_remove(struct platform_device *pdev) 152 { 153 struct usb_extcon_info *info = platform_get_drvdata(pdev); 154 155 cancel_delayed_work_sync(&info->wq_detcable); 156 157 return 0; 158 } 159 160 #ifdef CONFIG_PM_SLEEP 161 static int usb_extcon_suspend(struct device *dev) 162 { 163 struct usb_extcon_info *info = dev_get_drvdata(dev); 164 int ret = 0; 165 166 if (device_may_wakeup(dev)) { 167 ret = enable_irq_wake(info->id_irq); 168 if (ret) 169 return ret; 170 } 171 172 /* 173 * We don't want to process any IRQs after this point 174 * as GPIOs used behind I2C subsystem might not be 175 * accessible until resume completes. So disable IRQ. 176 */ 177 disable_irq(info->id_irq); 178 179 return ret; 180 } 181 182 static int usb_extcon_resume(struct device *dev) 183 { 184 struct usb_extcon_info *info = dev_get_drvdata(dev); 185 int ret = 0; 186 187 if (device_may_wakeup(dev)) { 188 ret = disable_irq_wake(info->id_irq); 189 if (ret) 190 return ret; 191 } 192 193 enable_irq(info->id_irq); 194 195 return ret; 196 } 197 #endif 198 199 static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops, 200 usb_extcon_suspend, usb_extcon_resume); 201 202 static const struct of_device_id usb_extcon_dt_match[] = { 203 { .compatible = "linux,extcon-usb-gpio", }, 204 { /* sentinel */ } 205 }; 206 MODULE_DEVICE_TABLE(of, usb_extcon_dt_match); 207 208 static struct platform_driver usb_extcon_driver = { 209 .probe = usb_extcon_probe, 210 .remove = usb_extcon_remove, 211 .driver = { 212 .name = "extcon-usb-gpio", 213 .pm = &usb_extcon_pm_ops, 214 .of_match_table = usb_extcon_dt_match, 215 }, 216 }; 217 218 module_platform_driver(usb_extcon_driver); 219 220 MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>"); 221 MODULE_DESCRIPTION("USB GPIO extcon driver"); 222 MODULE_LICENSE("GPL v2"); 223