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/init.h> 19 #include <linux/interrupt.h> 20 #include <linux/irq.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/of_gpio.h> 24 #include <linux/platform_device.h> 25 #include <linux/slab.h> 26 #include <linux/workqueue.h> 27 28 #define USB_GPIO_DEBOUNCE_MS 20 /* ms */ 29 30 struct usb_extcon_info { 31 struct device *dev; 32 struct extcon_dev *edev; 33 34 struct gpio_desc *id_gpiod; 35 int id_irq; 36 37 unsigned long debounce_jiffies; 38 struct delayed_work wq_detcable; 39 }; 40 41 /* List of detectable cables */ 42 enum { 43 EXTCON_CABLE_USB = 0, 44 EXTCON_CABLE_USB_HOST, 45 46 EXTCON_CABLE_END, 47 }; 48 49 static const char *usb_extcon_cable[] = { 50 [EXTCON_CABLE_USB] = "USB", 51 [EXTCON_CABLE_USB_HOST] = "USB-HOST", 52 NULL, 53 }; 54 55 static void usb_extcon_detect_cable(struct work_struct *work) 56 { 57 int id; 58 struct usb_extcon_info *info = container_of(to_delayed_work(work), 59 struct usb_extcon_info, 60 wq_detcable); 61 62 /* check ID and update cable state */ 63 id = gpiod_get_value_cansleep(info->id_gpiod); 64 if (id) { 65 /* 66 * ID = 1 means USB HOST cable detached. 67 * As we don't have event for USB peripheral cable attached, 68 * we simulate USB peripheral attach here. 69 */ 70 extcon_set_cable_state(info->edev, 71 usb_extcon_cable[EXTCON_CABLE_USB_HOST], 72 false); 73 extcon_set_cable_state(info->edev, 74 usb_extcon_cable[EXTCON_CABLE_USB], 75 true); 76 } else { 77 /* 78 * ID = 0 means USB HOST cable attached. 79 * As we don't have event for USB peripheral cable detached, 80 * we simulate USB peripheral detach here. 81 */ 82 extcon_set_cable_state(info->edev, 83 usb_extcon_cable[EXTCON_CABLE_USB], 84 false); 85 extcon_set_cable_state(info->edev, 86 usb_extcon_cable[EXTCON_CABLE_USB_HOST], 87 true); 88 } 89 } 90 91 static irqreturn_t usb_irq_handler(int irq, void *dev_id) 92 { 93 struct usb_extcon_info *info = dev_id; 94 95 queue_delayed_work(system_power_efficient_wq, &info->wq_detcable, 96 info->debounce_jiffies); 97 98 return IRQ_HANDLED; 99 } 100 101 static int usb_extcon_probe(struct platform_device *pdev) 102 { 103 struct device *dev = &pdev->dev; 104 struct device_node *np = dev->of_node; 105 struct usb_extcon_info *info; 106 int ret; 107 108 if (!np) 109 return -EINVAL; 110 111 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); 112 if (!info) 113 return -ENOMEM; 114 115 info->dev = dev; 116 info->id_gpiod = devm_gpiod_get(&pdev->dev, "id"); 117 if (IS_ERR(info->id_gpiod)) { 118 dev_err(dev, "failed to get ID GPIO\n"); 119 return PTR_ERR(info->id_gpiod); 120 } 121 122 info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable); 123 if (IS_ERR(info->edev)) { 124 dev_err(dev, "failed to allocate extcon device\n"); 125 return -ENOMEM; 126 } 127 128 ret = devm_extcon_dev_register(dev, info->edev); 129 if (ret < 0) { 130 dev_err(dev, "failed to register extcon device\n"); 131 return ret; 132 } 133 134 ret = gpiod_set_debounce(info->id_gpiod, 135 USB_GPIO_DEBOUNCE_MS * 1000); 136 if (ret < 0) 137 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS); 138 139 INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable); 140 141 info->id_irq = gpiod_to_irq(info->id_gpiod); 142 if (info->id_irq < 0) { 143 dev_err(dev, "failed to get ID IRQ\n"); 144 return info->id_irq; 145 } 146 147 ret = devm_request_threaded_irq(dev, info->id_irq, NULL, 148 usb_irq_handler, 149 IRQF_TRIGGER_RISING | 150 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 151 pdev->name, info); 152 if (ret < 0) { 153 dev_err(dev, "failed to request handler for ID IRQ\n"); 154 return ret; 155 } 156 157 platform_set_drvdata(pdev, info); 158 device_init_wakeup(dev, 1); 159 160 /* Perform initial detection */ 161 usb_extcon_detect_cable(&info->wq_detcable.work); 162 163 return 0; 164 } 165 166 static int usb_extcon_remove(struct platform_device *pdev) 167 { 168 struct usb_extcon_info *info = platform_get_drvdata(pdev); 169 170 cancel_delayed_work_sync(&info->wq_detcable); 171 172 return 0; 173 } 174 175 #ifdef CONFIG_PM_SLEEP 176 static int usb_extcon_suspend(struct device *dev) 177 { 178 struct usb_extcon_info *info = dev_get_drvdata(dev); 179 int ret = 0; 180 181 if (device_may_wakeup(dev)) { 182 ret = enable_irq_wake(info->id_irq); 183 if (ret) 184 return ret; 185 } 186 187 /* 188 * We don't want to process any IRQs after this point 189 * as GPIOs used behind I2C subsystem might not be 190 * accessible until resume completes. So disable IRQ. 191 */ 192 disable_irq(info->id_irq); 193 194 return ret; 195 } 196 197 static int usb_extcon_resume(struct device *dev) 198 { 199 struct usb_extcon_info *info = dev_get_drvdata(dev); 200 int ret = 0; 201 202 if (device_may_wakeup(dev)) { 203 ret = disable_irq_wake(info->id_irq); 204 if (ret) 205 return ret; 206 } 207 208 enable_irq(info->id_irq); 209 210 return ret; 211 } 212 #endif 213 214 static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops, 215 usb_extcon_suspend, usb_extcon_resume); 216 217 static const struct of_device_id usb_extcon_dt_match[] = { 218 { .compatible = "linux,extcon-usb-gpio", }, 219 { /* sentinel */ } 220 }; 221 MODULE_DEVICE_TABLE(of, usb_extcon_dt_match); 222 223 static struct platform_driver usb_extcon_driver = { 224 .probe = usb_extcon_probe, 225 .remove = usb_extcon_remove, 226 .driver = { 227 .name = "extcon-usb-gpio", 228 .pm = &usb_extcon_pm_ops, 229 .of_match_table = usb_extcon_dt_match, 230 }, 231 }; 232 233 module_platform_driver(usb_extcon_driver); 234 235 MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>"); 236 MODULE_DESCRIPTION("USB GPIO extcon driver"); 237 MODULE_LICENSE("GPL v2"); 238