1/*
2 *  drivers/switch/switch_class.c
3 *
4 * Copyright (C) 2008 Google, Inc.
5 * Author: Mike Lockwood <lockwood@android.com>
6 *
7 * This software is licensed under the terms of the GNU General Public
8 * License version 2, as published by the Free Software Foundation, and
9 * may be copied, distributed, and modified under those terms.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16*/
17
18#include <linux/module.h>
19#include <linux/types.h>
20#include <linux/init.h>
21#include <linux/device.h>
22#include <linux/fs.h>
23#include <linux/err.h>
24#include <linux/switch.h>
25
26struct class *switch_class;
27static atomic_t device_count;
28
29static ssize_t state_show(struct device *dev, struct device_attribute *attr,
30		char *buf)
31{
32	struct switch_dev *sdev = (struct switch_dev *)
33		dev_get_drvdata(dev);
34
35	if (sdev->print_state) {
36		int ret = sdev->print_state(sdev, buf);
37		if (ret >= 0)
38			return ret;
39	}
40	return sprintf(buf, "%d\n", sdev->state);
41}
42
43static ssize_t name_show(struct device *dev, struct device_attribute *attr,
44		char *buf)
45{
46	struct switch_dev *sdev = (struct switch_dev *)
47		dev_get_drvdata(dev);
48
49	if (sdev->print_name) {
50		int ret = sdev->print_name(sdev, buf);
51		if (ret >= 0)
52			return ret;
53	}
54	return sprintf(buf, "%s\n", sdev->name);
55}
56
57static DEVICE_ATTR(state, S_IRUGO | S_IWUSR, state_show, NULL);
58static DEVICE_ATTR(name, S_IRUGO | S_IWUSR, name_show, NULL);
59
60void switch_set_state(struct switch_dev *sdev, int state)
61{
62	char name_buf[120];
63	char state_buf[120];
64	char *prop_buf;
65	char *envp[3];
66	int env_offset = 0;
67	int length;
68
69	if (sdev->state != state) {
70		sdev->state = state;
71
72		prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
73		if (prop_buf) {
74			length = name_show(sdev->dev, NULL, prop_buf);
75			if (length > 0) {
76				if (prop_buf[length - 1] == '\n')
77					prop_buf[length - 1] = 0;
78				snprintf(name_buf, sizeof(name_buf),
79					"SWITCH_NAME=%s", prop_buf);
80				envp[env_offset++] = name_buf;
81			}
82			length = state_show(sdev->dev, NULL, prop_buf);
83			if (length > 0) {
84				if (prop_buf[length - 1] == '\n')
85					prop_buf[length - 1] = 0;
86				snprintf(state_buf, sizeof(state_buf),
87					"SWITCH_STATE=%s", prop_buf);
88				envp[env_offset++] = state_buf;
89			}
90			envp[env_offset] = NULL;
91			kobject_uevent_env(&sdev->dev->kobj, KOBJ_CHANGE, envp);
92			free_page((unsigned long)prop_buf);
93		} else {
94			printk(KERN_ERR "out of memory in switch_set_state\n");
95			kobject_uevent(&sdev->dev->kobj, KOBJ_CHANGE);
96		}
97	}
98}
99EXPORT_SYMBOL_GPL(switch_set_state);
100
101static int create_switch_class(void)
102{
103	if (!switch_class) {
104		switch_class = class_create(THIS_MODULE, "switch");
105		if (IS_ERR(switch_class))
106			return PTR_ERR(switch_class);
107		atomic_set(&device_count, 0);
108	}
109
110	return 0;
111}
112
113int switch_dev_register(struct switch_dev *sdev)
114{
115	int ret;
116
117	if (!switch_class) {
118		ret = create_switch_class();
119		if (ret < 0)
120			return ret;
121	}
122
123	sdev->index = atomic_inc_return(&device_count);
124	sdev->dev = device_create(switch_class, NULL,
125		MKDEV(0, sdev->index), NULL, sdev->name);
126	if (IS_ERR(sdev->dev))
127		return PTR_ERR(sdev->dev);
128
129	ret = device_create_file(sdev->dev, &dev_attr_state);
130	if (ret < 0)
131		goto err_create_file_1;
132	ret = device_create_file(sdev->dev, &dev_attr_name);
133	if (ret < 0)
134		goto err_create_file_2;
135
136	dev_set_drvdata(sdev->dev, sdev);
137	sdev->state = 0;
138	return 0;
139
140err_create_file_2:
141	device_remove_file(sdev->dev, &dev_attr_state);
142err_create_file_1:
143	device_destroy(switch_class, MKDEV(0, sdev->index));
144	printk(KERN_ERR "switch: Failed to register driver %s\n", sdev->name);
145
146	return ret;
147}
148EXPORT_SYMBOL_GPL(switch_dev_register);
149
150void switch_dev_unregister(struct switch_dev *sdev)
151{
152	device_remove_file(sdev->dev, &dev_attr_name);
153	device_remove_file(sdev->dev, &dev_attr_state);
154	device_destroy(switch_class, MKDEV(0, sdev->index));
155	dev_set_drvdata(sdev->dev, NULL);
156}
157EXPORT_SYMBOL_GPL(switch_dev_unregister);
158
159static int __init switch_class_init(void)
160{
161	return create_switch_class();
162}
163
164static void __exit switch_class_exit(void)
165{
166	class_destroy(switch_class);
167}
168
169module_init(switch_class_init);
170module_exit(switch_class_exit);
171
172MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
173MODULE_DESCRIPTION("Switch class driver");
174MODULE_LICENSE("GPL");
175