Greg Kroah-Hartman | 355b050 | 2011-11-30 20:18:14 +0900 | [diff] [blame] | 1 | /* drivers/misc/timed_output.c |
| 2 | * |
| 3 | * Copyright (C) 2009 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 | |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 17 | #define pr_fmt(fmt) "timed_output: " fmt |
| 18 | |
Greg Kroah-Hartman | 355b050 | 2011-11-30 20:18:14 +0900 | [diff] [blame] | 19 | #include <linux/module.h> |
| 20 | #include <linux/types.h> |
| 21 | #include <linux/device.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include <linux/err.h> |
| 24 | |
| 25 | #include "timed_output.h" |
| 26 | |
| 27 | static struct class *timed_output_class; |
| 28 | static atomic_t device_count; |
| 29 | |
| 30 | static ssize_t enable_show(struct device *dev, struct device_attribute *attr, |
| 31 | char *buf) |
| 32 | { |
| 33 | struct timed_output_dev *tdev = dev_get_drvdata(dev); |
| 34 | int remaining = tdev->get_time(tdev); |
| 35 | |
| 36 | return sprintf(buf, "%d\n", remaining); |
| 37 | } |
| 38 | |
| 39 | static ssize_t enable_store( |
| 40 | struct device *dev, struct device_attribute *attr, |
| 41 | const char *buf, size_t size) |
| 42 | { |
| 43 | struct timed_output_dev *tdev = dev_get_drvdata(dev); |
| 44 | int value; |
| 45 | |
Mike Lockwood | 8bfe15f | 2010-04-17 12:01:35 -0400 | [diff] [blame] | 46 | if (sscanf(buf, "%d", &value) != 1) |
| 47 | return -EINVAL; |
| 48 | |
Greg Kroah-Hartman | 355b050 | 2011-11-30 20:18:14 +0900 | [diff] [blame] | 49 | tdev->enable(tdev, value); |
| 50 | |
| 51 | return size; |
| 52 | } |
| 53 | |
| 54 | static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, enable_show, enable_store); |
| 55 | |
| 56 | static int create_timed_output_class(void) |
| 57 | { |
| 58 | if (!timed_output_class) { |
| 59 | timed_output_class = class_create(THIS_MODULE, "timed_output"); |
| 60 | if (IS_ERR(timed_output_class)) |
| 61 | return PTR_ERR(timed_output_class); |
| 62 | atomic_set(&device_count, 0); |
| 63 | } |
| 64 | |
| 65 | return 0; |
| 66 | } |
| 67 | |
| 68 | int timed_output_dev_register(struct timed_output_dev *tdev) |
| 69 | { |
| 70 | int ret; |
| 71 | |
| 72 | if (!tdev || !tdev->name || !tdev->enable || !tdev->get_time) |
| 73 | return -EINVAL; |
| 74 | |
| 75 | ret = create_timed_output_class(); |
| 76 | if (ret < 0) |
| 77 | return ret; |
| 78 | |
| 79 | tdev->index = atomic_inc_return(&device_count); |
| 80 | tdev->dev = device_create(timed_output_class, NULL, |
| 81 | MKDEV(0, tdev->index), NULL, tdev->name); |
| 82 | if (IS_ERR(tdev->dev)) |
| 83 | return PTR_ERR(tdev->dev); |
| 84 | |
| 85 | ret = device_create_file(tdev->dev, &dev_attr_enable); |
| 86 | if (ret < 0) |
| 87 | goto err_create_file; |
| 88 | |
| 89 | dev_set_drvdata(tdev->dev, tdev); |
| 90 | tdev->state = 0; |
| 91 | return 0; |
| 92 | |
| 93 | err_create_file: |
| 94 | device_destroy(timed_output_class, MKDEV(0, tdev->index)); |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 95 | pr_err("failed to register driver %s\n", |
Greg Kroah-Hartman | 355b050 | 2011-11-30 20:18:14 +0900 | [diff] [blame] | 96 | tdev->name); |
| 97 | |
| 98 | return ret; |
| 99 | } |
| 100 | EXPORT_SYMBOL_GPL(timed_output_dev_register); |
| 101 | |
| 102 | void timed_output_dev_unregister(struct timed_output_dev *tdev) |
| 103 | { |
Kim, Milo | d9a861d | 2012-04-26 22:01:10 -0700 | [diff] [blame] | 104 | tdev->enable(tdev, 0); |
Greg Kroah-Hartman | 355b050 | 2011-11-30 20:18:14 +0900 | [diff] [blame] | 105 | device_remove_file(tdev->dev, &dev_attr_enable); |
| 106 | device_destroy(timed_output_class, MKDEV(0, tdev->index)); |
| 107 | dev_set_drvdata(tdev->dev, NULL); |
| 108 | } |
| 109 | EXPORT_SYMBOL_GPL(timed_output_dev_unregister); |
| 110 | |
| 111 | static int __init timed_output_init(void) |
| 112 | { |
| 113 | return create_timed_output_class(); |
| 114 | } |
| 115 | |
| 116 | static void __exit timed_output_exit(void) |
| 117 | { |
| 118 | class_destroy(timed_output_class); |
| 119 | } |
| 120 | |
| 121 | module_init(timed_output_init); |
| 122 | module_exit(timed_output_exit); |
| 123 | |
| 124 | MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); |
| 125 | MODULE_DESCRIPTION("timed output class driver"); |
| 126 | MODULE_LICENSE("GPL"); |