drivers/extcon/extcon-gpio.c

   1 /*
   2  *  drivers/extcon/extcon_gpio.c
   3  *
   4  *  Single-state GPIO extcon driver based on extcon class
   5  *
   6  * Copyright (C) 2008 Google, Inc.
   7  * Author: Mike Lockwood <lockwood@android.com>
   8  *
   9  * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
  10  * (originally switch class is supported)
  11  *
  12  * This software is licensed under the terms of the GNU General Public
  13  * License version 2, as published by the Free Software Foundation, and
  14  * may be copied, distributed, and modified under those terms.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21 */
  22
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/init.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/slab.h>
  29 #include <linux/workqueue.h>
  30 #include <linux/gpio.h>
  31 #include <linux/extcon.h>
  32 #include <linux/extcon/extcon-gpio.h>
  33
  34 struct gpio_extcon_data {
  35         struct extcon_dev *edev;
  36         unsigned gpio;
  37         bool gpio_active_low;
  38         const char *state_on;
  39         const char *state_off;
  40         int irq;
  41         struct delayed_work work;
  42         unsigned long debounce_jiffies;
  43         bool check_on_resume;
  44 };
  45
  46 static void gpio_extcon_work(struct work_struct *work)
  47 {
  48         int state;
  49         struct gpio_extcon_data *data =
  50                 container_of(to_delayed_work(work), struct gpio_extcon_data,
  51                              work);
  52
  53         state = gpio_get_value(data->gpio);
  54         if (data->gpio_active_low)
  55                 state = !state;
  56         extcon_set_state(data->edev, state);
  57 }
  58
  59 static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
  60 {
  61         struct gpio_extcon_data *extcon_data = dev_id;
  62
  63         queue_delayed_work(system_power_efficient_wq, &extcon_data->work,
  64                               extcon_data->debounce_jiffies);
  65         return IRQ_HANDLED;
  66 }
  67
  68 static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf)
  69 {
  70         struct device *dev = edev->dev.parent;
  71         struct gpio_extcon_data *extcon_data = dev_get_drvdata(dev);
  72         const char *state;
  73
  74         if (extcon_get_state(edev))
  75                 state = extcon_data->state_on;
  76         else
  77                 state = extcon_data->state_off;
  78
  79         if (state)
  80                 return sprintf(buf, "%s\n", state);
  81         return -EINVAL;
  82 }
  83
  84 static int gpio_extcon_probe(struct platform_device *pdev)
  85 {
  86         struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev);
  87         struct gpio_extcon_data *extcon_data;
  88         int ret;
  89
  90         if (!pdata)
  91                 return -EBUSY;
  92         if (!pdata->irq_flags) {
  93                 dev_err(&pdev->dev, "IRQ flag is not specified.\n");
  94                 return -EINVAL;
  95         }
  96
  97         extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
  98                                    GFP_KERNEL);
  99         if (!extcon_data)
 100                 return -ENOMEM;
 101
 102         extcon_data->edev = devm_extcon_dev_allocate(&pdev->dev, NULL);
 103         if (IS_ERR(extcon_data->edev)) {
 104                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
 105                 return -ENOMEM;
 106         }
 107         extcon_data->edev->name = pdata->name;
 108
 109         extcon_data->gpio = pdata->gpio;
 110         extcon_data->gpio_active_low = pdata->gpio_active_low;
 111         extcon_data->state_on = pdata->state_on;
 112         extcon_data->state_off = pdata->state_off;
 113         extcon_data->check_on_resume = pdata->check_on_resume;
 114         if (pdata->state_on && pdata->state_off)
 115                 extcon_data->edev->print_state = extcon_gpio_print_state;
 116
 117         ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
 118                                     pdev->name);
 119         if (ret < 0)
 120                 return ret;
 121
 122         if (pdata->debounce) {
 123                 ret = gpio_set_debounce(extcon_data->gpio,
 124                                         pdata->debounce * 1000);
 125                 if (ret < 0)
 126                         extcon_data->debounce_jiffies =
 127                                 msecs_to_jiffies(pdata->debounce);
 128         }
 129
 130         ret = devm_extcon_dev_register(&pdev->dev, extcon_data->edev);
 131         if (ret < 0)
 132                 return ret;
 133
 134         INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
 135
 136         extcon_data->irq = gpio_to_irq(extcon_data->gpio);
 137         if (extcon_data->irq < 0)
 138                 return extcon_data->irq;
 139
 140         ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler,
 141                                       pdata->irq_flags, pdev->name,
 142                                       extcon_data);
 143         if (ret < 0)
 144                 return ret;
 145
 146         platform_set_drvdata(pdev, extcon_data);
 147         /* Perform initial detection */
 148         gpio_extcon_work(&extcon_data->work.work);
 149
 150         return 0;
 151 }
 152
 153 static int gpio_extcon_remove(struct platform_device *pdev)
 154 {
 155         struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev);
 156
 157         cancel_delayed_work_sync(&extcon_data->work);
 158         free_irq(extcon_data->irq, extcon_data);
 159
 160         return 0;
 161 }
 162
 163 #ifdef CONFIG_PM_SLEEP
 164 static int gpio_extcon_resume(struct device *dev)
 165 {
 166         struct gpio_extcon_data *extcon_data;
 167
 168         extcon_data = dev_get_drvdata(dev);
 169         if (extcon_data->check_on_resume)
 170                 queue_delayed_work(system_power_efficient_wq,
 171                         &extcon_data->work, extcon_data->debounce_jiffies);
 172
 173         return 0;
 174 }
 175 #endif
 176
 177 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
 178
 179 static struct platform_driver gpio_extcon_driver = {
 180         .probe          = gpio_extcon_probe,
 181         .remove         = gpio_extcon_remove,
 182         .driver         = {
 183                 .name   = "extcon-gpio",
 184                 .owner  = THIS_MODULE,
 185                 .pm     = &gpio_extcon_pm_ops,
 186         },
 187 };
 188
 189 module_platform_driver(gpio_extcon_driver);
 190
 191 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
 192 MODULE_DESCRIPTION("GPIO extcon driver");
 193 MODULE_LICENSE("GPL");