ACPI / scan: Remove unnecessary initialization of local variables
[linux-3.10.git] / drivers / acpi / fan.c
1 /*
2  *  acpi_fan.c - ACPI Fan Driver ($Revision: 29 $)
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *
7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or (at
12  *  your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful, but
15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  *  General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
22  *
23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24  */
25
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/types.h>
30 #include <asm/uaccess.h>
31 #include <linux/thermal.h>
32 #include <acpi/acpi_bus.h>
33 #include <acpi/acpi_drivers.h>
34
35 #define PREFIX "ACPI: "
36
37 #define ACPI_FAN_CLASS                  "fan"
38 #define ACPI_FAN_FILE_STATE             "state"
39
40 #define _COMPONENT              ACPI_FAN_COMPONENT
41 ACPI_MODULE_NAME("fan");
42
43 MODULE_AUTHOR("Paul Diefenbaugh");
44 MODULE_DESCRIPTION("ACPI Fan Driver");
45 MODULE_LICENSE("GPL");
46
47 static int acpi_fan_add(struct acpi_device *device);
48 static int acpi_fan_remove(struct acpi_device *device, int type);
49
50 static const struct acpi_device_id fan_device_ids[] = {
51         {"PNP0C0B", 0},
52         {"", 0},
53 };
54 MODULE_DEVICE_TABLE(acpi, fan_device_ids);
55
56 #ifdef CONFIG_PM_SLEEP
57 static int acpi_fan_suspend(struct device *dev);
58 static int acpi_fan_resume(struct device *dev);
59 #endif
60 static SIMPLE_DEV_PM_OPS(acpi_fan_pm, acpi_fan_suspend, acpi_fan_resume);
61
62 static struct acpi_driver acpi_fan_driver = {
63         .name = "fan",
64         .class = ACPI_FAN_CLASS,
65         .ids = fan_device_ids,
66         .ops = {
67                 .add = acpi_fan_add,
68                 .remove = acpi_fan_remove,
69                 },
70         .drv.pm = &acpi_fan_pm,
71 };
72
73 /* thermal cooling device callbacks */
74 static int fan_get_max_state(struct thermal_cooling_device *cdev, unsigned long
75                              *state)
76 {
77         /* ACPI fan device only support two states: ON/OFF */
78         *state = 1;
79         return 0;
80 }
81
82 static int fan_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
83                              *state)
84 {
85         struct acpi_device *device = cdev->devdata;
86         int result;
87         int acpi_state;
88
89         if (!device)
90                 return -EINVAL;
91
92         result = acpi_bus_update_power(device->handle, &acpi_state);
93         if (result)
94                 return result;
95
96         *state = (acpi_state == ACPI_STATE_D3 ? 0 :
97                  (acpi_state == ACPI_STATE_D0 ? 1 : -1));
98         return 0;
99 }
100
101 static int
102 fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
103 {
104         struct acpi_device *device = cdev->devdata;
105         int result;
106
107         if (!device || (state != 0 && state != 1))
108                 return -EINVAL;
109
110         result = acpi_bus_set_power(device->handle,
111                                 state ? ACPI_STATE_D0 : ACPI_STATE_D3);
112
113         return result;
114 }
115
116 static const struct thermal_cooling_device_ops fan_cooling_ops = {
117         .get_max_state = fan_get_max_state,
118         .get_cur_state = fan_get_cur_state,
119         .set_cur_state = fan_set_cur_state,
120 };
121
122 /* --------------------------------------------------------------------------
123                                  Driver Interface
124    -------------------------------------------------------------------------- */
125
126 static int acpi_fan_add(struct acpi_device *device)
127 {
128         int result = 0;
129         struct thermal_cooling_device *cdev;
130
131         if (!device)
132                 return -EINVAL;
133
134         strcpy(acpi_device_name(device), "Fan");
135         strcpy(acpi_device_class(device), ACPI_FAN_CLASS);
136
137         result = acpi_bus_update_power(device->handle, NULL);
138         if (result) {
139                 printk(KERN_ERR PREFIX "Setting initial power state\n");
140                 goto end;
141         }
142
143         cdev = thermal_cooling_device_register("Fan", device,
144                                                 &fan_cooling_ops);
145         if (IS_ERR(cdev)) {
146                 result = PTR_ERR(cdev);
147                 goto end;
148         }
149
150         dev_dbg(&device->dev, "registered as cooling_device%d\n", cdev->id);
151
152         device->driver_data = cdev;
153         result = sysfs_create_link(&device->dev.kobj,
154                                    &cdev->device.kobj,
155                                    "thermal_cooling");
156         if (result)
157                 dev_err(&device->dev, "Failed to create sysfs link "
158                         "'thermal_cooling'\n");
159
160         result = sysfs_create_link(&cdev->device.kobj,
161                                    &device->dev.kobj,
162                                    "device");
163         if (result)
164                 dev_err(&device->dev, "Failed to create sysfs link "
165                         "'device'\n");
166
167         printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
168                acpi_device_name(device), acpi_device_bid(device),
169                !device->power.state ? "on" : "off");
170
171       end:
172         return result;
173 }
174
175 static int acpi_fan_remove(struct acpi_device *device, int type)
176 {
177         struct thermal_cooling_device *cdev = acpi_driver_data(device);
178
179         if (!device || !cdev)
180                 return -EINVAL;
181
182         sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
183         sysfs_remove_link(&cdev->device.kobj, "device");
184         thermal_cooling_device_unregister(cdev);
185
186         return 0;
187 }
188
189 #ifdef CONFIG_PM_SLEEP
190 static int acpi_fan_suspend(struct device *dev)
191 {
192         if (!dev)
193                 return -EINVAL;
194
195         acpi_bus_set_power(to_acpi_device(dev)->handle, ACPI_STATE_D0);
196
197         return AE_OK;
198 }
199
200 static int acpi_fan_resume(struct device *dev)
201 {
202         int result;
203
204         if (!dev)
205                 return -EINVAL;
206
207         result = acpi_bus_update_power(to_acpi_device(dev)->handle, NULL);
208         if (result)
209                 printk(KERN_ERR PREFIX "Error updating fan power state\n");
210
211         return result;
212 }
213 #endif
214
215 module_acpi_driver(acpi_fan_driver);