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