ACPI: drivers/acpi: elide a non-zero test on a result that is never 0
[linux/fpc-iii.git] / drivers / acpi / fan.c
blob4d535c50d821e2a44d9fe3e9881b1d2d24213c02
1 /*
2 * acpi_fan.c - ACPI Fan Driver ($Revision: 29 $)
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
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.
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.
23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/types.h>
30 #include <linux/proc_fs.h>
31 #include <linux/seq_file.h>
32 #include <asm/uaccess.h>
33 #include <linux/thermal.h>
34 #include <acpi/acpi_bus.h>
35 #include <acpi/acpi_drivers.h>
37 #define ACPI_FAN_COMPONENT 0x00200000
38 #define ACPI_FAN_CLASS "fan"
39 #define ACPI_FAN_FILE_STATE "state"
41 #define _COMPONENT ACPI_FAN_COMPONENT
42 ACPI_MODULE_NAME("fan");
44 MODULE_AUTHOR("Paul Diefenbaugh");
45 MODULE_DESCRIPTION("ACPI Fan Driver");
46 MODULE_LICENSE("GPL");
48 static int acpi_fan_add(struct acpi_device *device);
49 static int acpi_fan_remove(struct acpi_device *device, int type);
50 static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state);
51 static int acpi_fan_resume(struct acpi_device *device);
53 static const struct acpi_device_id fan_device_ids[] = {
54 {"PNP0C0B", 0},
55 {"", 0},
57 MODULE_DEVICE_TABLE(acpi, fan_device_ids);
59 static struct acpi_driver acpi_fan_driver = {
60 .name = "fan",
61 .class = ACPI_FAN_CLASS,
62 .ids = fan_device_ids,
63 .ops = {
64 .add = acpi_fan_add,
65 .remove = acpi_fan_remove,
66 .suspend = acpi_fan_suspend,
67 .resume = acpi_fan_resume,
71 /* thermal cooling device callbacks */
72 static int fan_get_max_state(struct thermal_cooling_device *cdev, char *buf)
74 /* ACPI fan device only support two states: ON/OFF */
75 return sprintf(buf, "1\n");
78 static int fan_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
80 struct acpi_device *device = cdev->devdata;
81 int state;
82 int result;
84 if (!device)
85 return -EINVAL;
87 result = acpi_bus_get_power(device->handle, &state);
88 if (result)
89 return result;
91 return sprintf(buf, "%s\n", state == ACPI_STATE_D3 ? "0" :
92 (state == ACPI_STATE_D0 ? "1" : "unknown"));
95 static int
96 fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
98 struct acpi_device *device = cdev->devdata;
99 int result;
101 if (!device || (state != 0 && state != 1))
102 return -EINVAL;
104 result = acpi_bus_set_power(device->handle,
105 state ? ACPI_STATE_D0 : ACPI_STATE_D3);
107 return result;
110 static struct thermal_cooling_device_ops fan_cooling_ops = {
111 .get_max_state = fan_get_max_state,
112 .get_cur_state = fan_get_cur_state,
113 .set_cur_state = fan_set_cur_state,
116 /* --------------------------------------------------------------------------
117 FS Interface (/proc)
118 -------------------------------------------------------------------------- */
119 #ifdef CONFIG_ACPI_PROCFS
121 static struct proc_dir_entry *acpi_fan_dir;
123 static int acpi_fan_read_state(struct seq_file *seq, void *offset)
125 struct acpi_device *device = seq->private;
126 int state = 0;
129 if (device) {
130 if (acpi_bus_get_power(device->handle, &state))
131 seq_printf(seq, "status: ERROR\n");
132 else
133 seq_printf(seq, "status: %s\n",
134 !state ? "on" : "off");
136 return 0;
139 static int acpi_fan_state_open_fs(struct inode *inode, struct file *file)
141 return single_open(file, acpi_fan_read_state, PDE(inode)->data);
144 static ssize_t
145 acpi_fan_write_state(struct file *file, const char __user * buffer,
146 size_t count, loff_t * ppos)
148 int result = 0;
149 struct seq_file *m = file->private_data;
150 struct acpi_device *device = m->private;
151 char state_string[12] = { '\0' };
153 if (count > sizeof(state_string) - 1)
154 return -EINVAL;
156 if (copy_from_user(state_string, buffer, count))
157 return -EFAULT;
159 state_string[count] = '\0';
161 result = acpi_bus_set_power(device->handle,
162 simple_strtoul(state_string, NULL, 0));
163 if (result)
164 return result;
166 return count;
169 static const struct file_operations acpi_fan_state_ops = {
170 .open = acpi_fan_state_open_fs,
171 .read = seq_read,
172 .write = acpi_fan_write_state,
173 .llseek = seq_lseek,
174 .release = single_release,
175 .owner = THIS_MODULE,
178 static int acpi_fan_add_fs(struct acpi_device *device)
180 struct proc_dir_entry *entry = NULL;
183 if (!device)
184 return -EINVAL;
186 if (!acpi_device_dir(device)) {
187 acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
188 acpi_fan_dir);
189 if (!acpi_device_dir(device))
190 return -ENODEV;
191 acpi_device_dir(device)->owner = THIS_MODULE;
194 /* 'status' [R/W] */
195 entry = create_proc_entry(ACPI_FAN_FILE_STATE,
196 S_IFREG | S_IRUGO | S_IWUSR,
197 acpi_device_dir(device));
198 if (!entry)
199 return -ENODEV;
200 else {
201 entry->proc_fops = &acpi_fan_state_ops;
202 entry->data = device;
203 entry->owner = THIS_MODULE;
206 return 0;
209 static int acpi_fan_remove_fs(struct acpi_device *device)
212 if (acpi_device_dir(device)) {
213 remove_proc_entry(ACPI_FAN_FILE_STATE, acpi_device_dir(device));
214 remove_proc_entry(acpi_device_bid(device), acpi_fan_dir);
215 acpi_device_dir(device) = NULL;
218 return 0;
220 #else
221 static int acpi_fan_add_fs(struct acpi_device *device)
223 return 0;
226 static int acpi_fan_remove_fs(struct acpi_device *device)
228 return 0;
230 #endif
231 /* --------------------------------------------------------------------------
232 Driver Interface
233 -------------------------------------------------------------------------- */
235 static int acpi_fan_add(struct acpi_device *device)
237 int result = 0;
238 int state = 0;
239 struct thermal_cooling_device *cdev;
241 if (!device)
242 return -EINVAL;
244 strcpy(acpi_device_name(device), "Fan");
245 strcpy(acpi_device_class(device), ACPI_FAN_CLASS);
247 result = acpi_bus_get_power(device->handle, &state);
248 if (result) {
249 printk(KERN_ERR PREFIX "Reading power state\n");
250 goto end;
253 device->flags.force_power_state = 1;
254 acpi_bus_set_power(device->handle, state);
255 device->flags.force_power_state = 0;
257 cdev = thermal_cooling_device_register("Fan", device,
258 &fan_cooling_ops);
259 if (IS_ERR(cdev)) {
260 result = PTR_ERR(cdev);
261 goto end;
263 printk(KERN_INFO PREFIX
264 "%s is registered as cooling_device%d\n",
265 device->dev.bus_id, cdev->id);
267 acpi_driver_data(device) = cdev;
268 result = sysfs_create_link(&device->dev.kobj,
269 &cdev->device.kobj,
270 "thermal_cooling");
271 if (result)
272 return result;
274 result = sysfs_create_link(&cdev->device.kobj,
275 &device->dev.kobj,
276 "device");
277 if (result)
278 return result;
280 result = acpi_fan_add_fs(device);
281 if (result)
282 goto end;
284 printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
285 acpi_device_name(device), acpi_device_bid(device),
286 !device->power.state ? "on" : "off");
288 end:
289 return result;
292 static int acpi_fan_remove(struct acpi_device *device, int type)
294 struct thermal_cooling_device *cdev = acpi_driver_data(device);
296 if (!device || !cdev)
297 return -EINVAL;
299 acpi_fan_remove_fs(device);
300 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
301 sysfs_remove_link(&cdev->device.kobj, "device");
302 thermal_cooling_device_unregister(cdev);
304 return 0;
307 static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state)
309 if (!device)
310 return -EINVAL;
312 acpi_bus_set_power(device->handle, ACPI_STATE_D0);
314 return AE_OK;
317 static int acpi_fan_resume(struct acpi_device *device)
319 int result = 0;
320 int power_state = 0;
322 if (!device)
323 return -EINVAL;
325 result = acpi_bus_get_power(device->handle, &power_state);
326 if (result) {
327 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
328 "Error reading fan power state\n"));
329 return result;
332 device->flags.force_power_state = 1;
333 acpi_bus_set_power(device->handle, power_state);
334 device->flags.force_power_state = 0;
336 return result;
339 static int __init acpi_fan_init(void)
341 int result = 0;
344 #ifdef CONFIG_ACPI_PROCFS
345 acpi_fan_dir = proc_mkdir(ACPI_FAN_CLASS, acpi_root_dir);
346 if (!acpi_fan_dir)
347 return -ENODEV;
348 acpi_fan_dir->owner = THIS_MODULE;
349 #endif
351 result = acpi_bus_register_driver(&acpi_fan_driver);
352 if (result < 0) {
353 remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
354 return -ENODEV;
357 return 0;
360 static void __exit acpi_fan_exit(void)
363 acpi_bus_unregister_driver(&acpi_fan_driver);
365 remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
367 return;
370 module_init(acpi_fan_init);
371 module_exit(acpi_fan_exit);