Version:  2.0.40 2.2.26 2.4.37 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0

Linux/drivers/staging/android/timed_gpio.c

  1 /* drivers/misc/timed_gpio.c
  2  *
  3  * Copyright (C) 2008 Google, Inc.
  4  * Author: Mike Lockwood <lockwood@android.com>
  5  *
  6  * This software is licensed under the terms of the GNU General Public
  7  * License version 2, as published by the Free Software Foundation, and
  8  * may be copied, distributed, and modified under those terms.
  9  *
 10  * This program is distributed in the hope that it will be useful,
 11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13  * GNU General Public License for more details.
 14  *
 15  */
 16 
 17 #include <linux/module.h>
 18 #include <linux/platform_device.h>
 19 #include <linux/slab.h>
 20 #include <linux/hrtimer.h>
 21 #include <linux/err.h>
 22 #include <linux/gpio.h>
 23 #include <linux/ktime.h>
 24 
 25 #include "timed_output.h"
 26 #include "timed_gpio.h"
 27 
 28 
 29 struct timed_gpio_data {
 30         struct timed_output_dev dev;
 31         struct hrtimer timer;
 32         spinlock_t lock;
 33         unsigned gpio;
 34         int max_timeout;
 35         u8 active_low;
 36 };
 37 
 38 static enum hrtimer_restart gpio_timer_func(struct hrtimer *timer)
 39 {
 40         struct timed_gpio_data *data =
 41                 container_of(timer, struct timed_gpio_data, timer);
 42 
 43         gpio_direction_output(data->gpio, data->active_low ? 1 : 0);
 44         return HRTIMER_NORESTART;
 45 }
 46 
 47 static int gpio_get_time(struct timed_output_dev *dev)
 48 {
 49         struct timed_gpio_data *data;
 50         ktime_t t;
 51 
 52         data = container_of(dev, struct timed_gpio_data, dev);
 53 
 54         if (!hrtimer_active(&data->timer))
 55                 return 0;
 56 
 57         t = hrtimer_get_remaining(&data->timer);
 58 
 59         return ktime_to_ms(t);
 60 }
 61 
 62 static void gpio_enable(struct timed_output_dev *dev, int value)
 63 {
 64         struct timed_gpio_data  *data =
 65                 container_of(dev, struct timed_gpio_data, dev);
 66         unsigned long   flags;
 67 
 68         spin_lock_irqsave(&data->lock, flags);
 69 
 70         /* cancel previous timer and set GPIO according to value */
 71         hrtimer_cancel(&data->timer);
 72         gpio_direction_output(data->gpio, data->active_low ? !value : !!value);
 73 
 74         if (value > 0) {
 75                 if (value > data->max_timeout)
 76                         value = data->max_timeout;
 77 
 78                 hrtimer_start(&data->timer,
 79                         ktime_set(value / 1000, (value % 1000) * 1000000),
 80                         HRTIMER_MODE_REL);
 81         }
 82 
 83         spin_unlock_irqrestore(&data->lock, flags);
 84 }
 85 
 86 static int timed_gpio_probe(struct platform_device *pdev)
 87 {
 88         struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
 89         struct timed_gpio *cur_gpio;
 90         struct timed_gpio_data *gpio_data, *gpio_dat;
 91         int i, ret;
 92 
 93         if (!pdata)
 94                 return -EBUSY;
 95 
 96         gpio_data = devm_kzalloc(&pdev->dev,
 97                         sizeof(struct timed_gpio_data) * pdata->num_gpios,
 98                         GFP_KERNEL);
 99         if (!gpio_data)
100                 return -ENOMEM;
101 
102         for (i = 0; i < pdata->num_gpios; i++) {
103                 cur_gpio = &pdata->gpios[i];
104                 gpio_dat = &gpio_data[i];
105 
106                 hrtimer_init(&gpio_dat->timer, CLOCK_MONOTONIC,
107                                 HRTIMER_MODE_REL);
108                 gpio_dat->timer.function = gpio_timer_func;
109                 spin_lock_init(&gpio_dat->lock);
110 
111                 gpio_dat->dev.name = cur_gpio->name;
112                 gpio_dat->dev.get_time = gpio_get_time;
113                 gpio_dat->dev.enable = gpio_enable;
114                 ret = gpio_request(cur_gpio->gpio, cur_gpio->name);
115                 if (ret < 0)
116                         goto err_out;
117                 ret = timed_output_dev_register(&gpio_dat->dev);
118                 if (ret < 0) {
119                         gpio_free(cur_gpio->gpio);
120                         goto err_out;
121                 }
122 
123                 gpio_dat->gpio = cur_gpio->gpio;
124                 gpio_dat->max_timeout = cur_gpio->max_timeout;
125                 gpio_dat->active_low = cur_gpio->active_low;
126                 gpio_direction_output(gpio_dat->gpio, gpio_dat->active_low);
127         }
128 
129         platform_set_drvdata(pdev, gpio_data);
130 
131         return 0;
132 
133 err_out:
134         while (--i >= 0) {
135                 timed_output_dev_unregister(&gpio_data[i].dev);
136                 gpio_free(gpio_data[i].gpio);
137         }
138 
139         return ret;
140 }
141 
142 static int timed_gpio_remove(struct platform_device *pdev)
143 {
144         struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
145         struct timed_gpio_data *gpio_data = platform_get_drvdata(pdev);
146         int i;
147 
148         for (i = 0; i < pdata->num_gpios; i++) {
149                 timed_output_dev_unregister(&gpio_data[i].dev);
150                 gpio_free(gpio_data[i].gpio);
151         }
152 
153         return 0;
154 }
155 
156 static struct platform_driver timed_gpio_driver = {
157         .probe          = timed_gpio_probe,
158         .remove         = timed_gpio_remove,
159         .driver         = {
160                 .name           = TIMED_GPIO_NAME,
161         },
162 };
163 
164 module_platform_driver(timed_gpio_driver);
165 
166 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
167 MODULE_DESCRIPTION("timed gpio driver");
168 MODULE_LICENSE("GPL");
169 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us