kernel/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/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");