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Linux/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");
184 

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