drivers/extcon/extcon-gpio.c

   1 /*
   2  * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
   3  *
   4  * Copyright (C) 2008 Google, Inc.
   5  * Author: Mike Lockwood <lockwood@android.com>
   6  *
   7  * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
   8  * (originally switch class is supported)
   9  *
  10  * This software is licensed under the terms of the GNU General Public
  11  * License version 2, as published by the Free Software Foundation, and
  12  * may be copied, distributed, and modified under those terms.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <linux/extcon.h>
  21 #include <linux/extcon/extcon-gpio.h>
  22 #include <linux/gpio.h>
  23 #include <linux/gpio/consumer.h>
  24 #include <linux/init.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/slab.h>
  30 #include <linux/workqueue.h>
  31
  32 struct gpio_extcon_data {
  33         struct extcon_dev *edev;
  34         int irq;
  35         struct delayed_work work;
  36         unsigned long debounce_jiffies;
  37
  38         struct gpio_desc *id_gpiod;
  39         struct gpio_extcon_pdata *pdata;
  40 };
  41
  42 static void gpio_extcon_work(struct work_struct *work)
  43 {
  44         int state;
  45         struct gpio_extcon_data *data =
  46                 container_of(to_delayed_work(work), struct gpio_extcon_data,
  47                              work);
  48
  49         state = gpiod_get_value_cansleep(data->id_gpiod);
  50         if (data->pdata->gpio_active_low)
  51                 state = !state;
  52         extcon_set_state(data->edev, state);
  53 }
  54
  55 static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
  56 {
  57         struct gpio_extcon_data *data = dev_id;
  58
  59         queue_delayed_work(system_power_efficient_wq, &data->work,
  60                               data->debounce_jiffies);
  61         return IRQ_HANDLED;
  62 }
  63
  64 static int gpio_extcon_init(struct device *dev, struct gpio_extcon_data *data)
  65 {
  66         struct gpio_extcon_pdata *pdata = data->pdata;
  67         int ret;
  68
  69         ret = devm_gpio_request_one(dev, pdata->gpio, GPIOF_DIR_IN,
  70                                 dev_name(dev));
  71         if (ret < 0)
  72                 return ret;
  73
  74         data->id_gpiod = gpio_to_desc(pdata->gpio);
  75         if (!data->id_gpiod)
  76                 return -EINVAL;
  77
  78         if (pdata->debounce) {
  79                 ret = gpiod_set_debounce(data->id_gpiod,
  80                                         pdata->debounce * 1000);
  81                 if (ret < 0)
  82                         data->debounce_jiffies =
  83                                 msecs_to_jiffies(pdata->debounce);
  84         }
  85
  86         data->irq = gpiod_to_irq(data->id_gpiod);
  87         if (data->irq < 0)
  88                 return data->irq;
  89
  90         return 0;
  91 }
  92
  93 static int gpio_extcon_probe(struct platform_device *pdev)
  94 {
  95         struct gpio_extcon_pdata *pdata = dev_get_platdata(&pdev->dev);
  96         struct gpio_extcon_data *data;
  97         int ret;
  98
  99         if (!pdata)
 100                 return -EBUSY;
 101         if (!pdata->irq_flags || pdata->extcon_id > EXTCON_NONE)
 102                 return -EINVAL;
 103
 104         data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
 105                                    GFP_KERNEL);
 106         if (!data)
 107                 return -ENOMEM;
 108         data->pdata = pdata;
 109
 110         /* Initialize the gpio */
 111         ret = gpio_extcon_init(&pdev->dev, data);
 112         if (ret < 0)
 113                 return ret;
 114
 115         /* Allocate the memory of extcon devie and register extcon device */
 116         data->edev = devm_extcon_dev_allocate(&pdev->dev, &pdata->extcon_id);
 117         if (IS_ERR(data->edev)) {
 118                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
 119                 return -ENOMEM;
 120         }
 121
 122         ret = devm_extcon_dev_register(&pdev->dev, data->edev);
 123         if (ret < 0)
 124                 return ret;
 125
 126         INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
 127
 128         /*
 129          * Request the interrupt of gpio to detect whether external connector
 130          * is attached or detached.
 131          */
 132         ret = devm_request_any_context_irq(&pdev->dev, data->irq,
 133                                         gpio_irq_handler, pdata->irq_flags,
 134                                         pdev->name, data);
 135         if (ret < 0)
 136                 return ret;
 137
 138         platform_set_drvdata(pdev, data);
 139         /* Perform initial detection */
 140         gpio_extcon_work(&data->work.work);
 141
 142         return 0;
 143 }
 144
 145 static int gpio_extcon_remove(struct platform_device *pdev)
 146 {
 147         struct gpio_extcon_data *data = platform_get_drvdata(pdev);
 148
 149         cancel_delayed_work_sync(&data->work);
 150
 151         return 0;
 152 }
 153
 154 #ifdef CONFIG_PM_SLEEP
 155 static int gpio_extcon_resume(struct device *dev)
 156 {
 157         struct gpio_extcon_data *data;
 158
 159         data = dev_get_drvdata(dev);
 160         if (data->pdata->check_on_resume)
 161                 queue_delayed_work(system_power_efficient_wq,
 162                         &data->work, data->debounce_jiffies);
 163
 164         return 0;
 165 }
 166 #endif
 167
 168 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
 169
 170 static struct platform_driver gpio_extcon_driver = {
 171         .probe          = gpio_extcon_probe,
 172         .remove         = gpio_extcon_remove,
 173         .driver         = {
 174                 .name   = "extcon-gpio",
 175                 .pm     = &gpio_extcon_pm_ops,
 176         },
 177 };
 178
 179 module_platform_driver(gpio_extcon_driver);
 180
 181 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
 182 MODULE_DESCRIPTION("GPIO extcon driver");
 183 MODULE_LICENSE("GPL");