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 <[email protected]>
   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 #include <linux/acpi.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         struct gpio_desc *vbus_gpiod;
  39         int id_irq;
  40         int vbus_irq;
  41
  42         unsigned long debounce_jiffies;
  43         struct delayed_work wq_detcable;
  44 };
  45
  46 static const unsigned int usb_extcon_cable[] = {
  47         EXTCON_USB,
  48         EXTCON_USB_HOST,
  49         EXTCON_NONE,
  50 };
  51
  52 /*
  53  * "USB" = VBUS and "USB-HOST" = !ID, so we have:
  54  * Both "USB" and "USB-HOST" can't be set as active at the
  55  * same time so if "USB-HOST" is active (i.e. ID is 0)  we keep "USB" inactive
  56  * even if VBUS is on.
  57  *
  58  *  State              |    ID   |   VBUS
  59  * ----------------------------------------
  60  *  [1] USB            |    H    |    H
  61  *  [2] none           |    H    |    L
  62  *  [3] USB-HOST       |    L    |    H
  63  *  [4] USB-HOST       |    L    |    L
  64  *
  65  * In case we have only one of these signals:
  66  * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1.
  67  * - ID only - we want to distinguish between [1] and [4], so VBUS = ID.
  68 */
  69 static void usb_extcon_detect_cable(struct work_struct *work)
  70 {
  71         int id, vbus;
  72         struct usb_extcon_info *info = container_of(to_delayed_work(work),
  73                                                     struct usb_extcon_info,
  74                                                     wq_detcable);
  75
  76         /* check ID and VBUS and update cable state */
  77         id = info->id_gpiod ?
  78                 gpiod_get_value_cansleep(info->id_gpiod) : 1;
  79         vbus = info->vbus_gpiod ?
  80                 gpiod_get_value_cansleep(info->vbus_gpiod) : id;
  81
  82         /* at first we clean states which are no longer active */
  83         if (id)
  84                 extcon_set_state_sync(info->edev, EXTCON_USB_HOST, false);
  85         if (!vbus)
  86                 extcon_set_state_sync(info->edev, EXTCON_USB, false);
  87
  88         if (!id) {
  89                 extcon_set_state_sync(info->edev, EXTCON_USB_HOST, true);
  90         } else {
  91                 if (vbus)
  92                         extcon_set_state_sync(info->edev, EXTCON_USB, true);
  93         }
  94 }
  95
  96 static irqreturn_t usb_irq_handler(int irq, void *dev_id)
  97 {
  98         struct usb_extcon_info *info = dev_id;
  99
 100         queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
 101                            info->debounce_jiffies);
 102
 103         return IRQ_HANDLED;
 104 }
 105
 106 static int usb_extcon_probe(struct platform_device *pdev)
 107 {
 108         struct device *dev = &pdev->dev;
 109         struct device_node *np = dev->of_node;
 110         struct usb_extcon_info *info;
 111         int ret;
 112
 113         if (!np && !ACPI_HANDLE(dev))
 114                 return -EINVAL;
 115
 116         info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 117         if (!info)
 118                 return -ENOMEM;
 119
 120         info->dev = dev;
 121         info->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", GPIOD_IN);
 122         info->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus",
 123                                                    GPIOD_IN);
 124
 125         if (!info->id_gpiod && !info->vbus_gpiod) {
 126                 dev_err(dev, "failed to get gpios\n");
 127                 return -ENODEV;
 128         }
 129
 130         if (IS_ERR(info->id_gpiod))
 131                 return PTR_ERR(info->id_gpiod);
 132
 133         if (IS_ERR(info->vbus_gpiod))
 134                 return PTR_ERR(info->vbus_gpiod);
 135
 136         info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
 137         if (IS_ERR(info->edev)) {
 138                 dev_err(dev, "failed to allocate extcon device\n");
 139                 return -ENOMEM;
 140         }
 141
 142         ret = devm_extcon_dev_register(dev, info->edev);
 143         if (ret < 0) {
 144                 dev_err(dev, "failed to register extcon device\n");
 145                 return ret;
 146         }
 147
 148         if (info->id_gpiod)
 149                 ret = gpiod_set_debounce(info->id_gpiod,
 150                                          USB_GPIO_DEBOUNCE_MS * 1000);
 151         if (!ret && info->vbus_gpiod)
 152                 ret = gpiod_set_debounce(info->vbus_gpiod,
 153                                          USB_GPIO_DEBOUNCE_MS * 1000);
 154
 155         if (ret < 0)
 156                 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);
 157
 158         INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);
 159
 160         if (info->id_gpiod) {
 161                 info->id_irq = gpiod_to_irq(info->id_gpiod);
 162                 if (info->id_irq < 0) {
 163                         dev_err(dev, "failed to get ID IRQ\n");
 164                         return info->id_irq;
 165                 }
 166
 167                 ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
 168                                                 usb_irq_handler,
 169                                                 IRQF_TRIGGER_RISING |
 170                                                 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 171                                                 pdev->name, info);
 172                 if (ret < 0) {
 173                         dev_err(dev, "failed to request handler for ID IRQ\n");
 174                         return ret;
 175                 }
 176         }
 177
 178         if (info->vbus_gpiod) {
 179                 info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
 180                 if (info->vbus_irq < 0) {
 181                         dev_err(dev, "failed to get VBUS IRQ\n");
 182                         return info->vbus_irq;
 183                 }
 184
 185                 ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
 186                                                 usb_irq_handler,
 187                                                 IRQF_TRIGGER_RISING |
 188                                                 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 189                                                 pdev->name, info);
 190                 if (ret < 0) {
 191                         dev_err(dev, "failed to request handler for VBUS IRQ\n");
 192                         return ret;
 193                 }
 194         }
 195
 196         platform_set_drvdata(pdev, info);
 197         device_init_wakeup(dev, true);
 198
 199         /* Perform initial detection */
 200         usb_extcon_detect_cable(&info->wq_detcable.work);
 201
 202         return 0;
 203 }
 204
 205 static int usb_extcon_remove(struct platform_device *pdev)
 206 {
 207         struct usb_extcon_info *info = platform_get_drvdata(pdev);
 208
 209         cancel_delayed_work_sync(&info->wq_detcable);
 210         device_init_wakeup(&pdev->dev, false);
 211
 212         return 0;
 213 }
 214
 215 #ifdef CONFIG_PM_SLEEP
 216 static int usb_extcon_suspend(struct device *dev)
 217 {
 218         struct usb_extcon_info *info = dev_get_drvdata(dev);
 219         int ret = 0;
 220
 221         if (device_may_wakeup(dev)) {
 222                 if (info->id_gpiod) {
 223                         ret = enable_irq_wake(info->id_irq);
 224                         if (ret)
 225                                 return ret;
 226                 }
 227                 if (info->vbus_gpiod) {
 228                         ret = enable_irq_wake(info->vbus_irq);
 229                         if (ret) {
 230                                 if (info->id_gpiod)
 231                                         disable_irq_wake(info->id_irq);
 232
 233                                 return ret;
 234                         }
 235                 }
 236         }
 237
 238         /*
 239          * We don't want to process any IRQs after this point
 240          * as GPIOs used behind I2C subsystem might not be
 241          * accessible until resume completes. So disable IRQ.
 242          */
 243         if (info->id_gpiod)
 244                 disable_irq(info->id_irq);
 245         if (info->vbus_gpiod)
 246                 disable_irq(info->vbus_irq);
 247
 248         return ret;
 249 }
 250
 251 static int usb_extcon_resume(struct device *dev)
 252 {
 253         struct usb_extcon_info *info = dev_get_drvdata(dev);
 254         int ret = 0;
 255
 256         if (device_may_wakeup(dev)) {
 257                 if (info->id_gpiod) {
 258                         ret = disable_irq_wake(info->id_irq);
 259                         if (ret)
 260                                 return ret;
 261                 }
 262                 if (info->vbus_gpiod) {
 263                         ret = disable_irq_wake(info->vbus_irq);
 264                         if (ret) {
 265                                 if (info->id_gpiod)
 266                                         enable_irq_wake(info->id_irq);
 267
 268                                 return ret;
 269                         }
 270                 }
 271         }
 272
 273         if (info->id_gpiod)
 274                 enable_irq(info->id_irq);
 275         if (info->vbus_gpiod)
 276                 enable_irq(info->vbus_irq);
 277
 278         if (!device_may_wakeup(dev))
 279                 queue_delayed_work(system_power_efficient_wq,
 280                                    &info->wq_detcable, 0);
 281
 282         return ret;
 283 }
 284 #endif
 285
 286 static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops,
 287                          usb_extcon_suspend, usb_extcon_resume);
 288
 289 static const struct of_device_id usb_extcon_dt_match[] = {
 290         { .compatible = "linux,extcon-usb-gpio", },
 291         { /* sentinel */ }
 292 };
 293 MODULE_DEVICE_TABLE(of, usb_extcon_dt_match);
 294
 295 static const struct platform_device_id usb_extcon_platform_ids[] = {
 296         { .name = "extcon-usb-gpio", },
 297         { /* sentinel */ }
 298 };
 299 MODULE_DEVICE_TABLE(platform, usb_extcon_platform_ids);
 300
 301 static struct platform_driver usb_extcon_driver = {
 302         .probe          = usb_extcon_probe,
 303         .remove         = usb_extcon_remove,
 304         .driver         = {
 305                 .name   = "extcon-usb-gpio",
 306                 .pm     = &usb_extcon_pm_ops,
 307                 .of_match_table = usb_extcon_dt_match,
 308         },
 309         .id_table = usb_extcon_platform_ids,
 310 };
 311
 312 module_platform_driver(usb_extcon_driver);
 313
 314 MODULE_AUTHOR("Roger Quadros <[email protected]>");
 315 MODULE_DESCRIPTION("USB GPIO extcon driver");
 316 MODULE_LICENSE("GPL v2");