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