drivers/extcon/extcon-usb-gpio.c

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