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