Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 <linux/proc_fs.h>
 31 #include <linux/seq_file.h>
 32 #include <asm/uaccess.h>
 33 
 34 #include <acpi/acpi_bus.h>
 35 #include <acpi/acpi_drivers.h>
 36 
 37 
 38 #define ACPI_FAN_COMPONENT              0x00200000
 39 #define ACPI_FAN_CLASS                  "fan"
 40 #define ACPI_FAN_HID                    "PNP0C0B"
 41 #define ACPI_FAN_DRIVER_NAME            "ACPI Fan Driver"
 42 #define ACPI_FAN_DEVICE_NAME            "Fan"
 43 #define ACPI_FAN_FILE_STATE             "state"
 44 #define ACPI_FAN_NOTIFY_STATUS          0x80
 45 
 46 #define _COMPONENT              ACPI_FAN_COMPONENT
 47 ACPI_MODULE_NAME                ("acpi_fan")
 48 
 49 MODULE_AUTHOR("Paul Diefenbaugh");
 50 MODULE_DESCRIPTION(ACPI_FAN_DRIVER_NAME);
 51 MODULE_LICENSE("GPL");
 52 
 53 int acpi_fan_add (struct acpi_device *device);
 54 int acpi_fan_remove (struct acpi_device *device, int type);
 55 
 56 static struct acpi_driver acpi_fan_driver = {
 57         .name =         ACPI_FAN_DRIVER_NAME,
 58         .class =        ACPI_FAN_CLASS,
 59         .ids =          ACPI_FAN_HID,
 60         .ops =          {
 61                                 .add =          acpi_fan_add,
 62                                 .remove =       acpi_fan_remove,
 63                         },
 64 };
 65 
 66 struct acpi_fan {
 67         acpi_handle             handle;
 68 };
 69 
 70 
 71 /* --------------------------------------------------------------------------
 72                               FS Interface (/proc)
 73    -------------------------------------------------------------------------- */
 74 
 75 struct proc_dir_entry           *acpi_fan_dir;
 76 
 77 
 78 static int
 79 acpi_fan_read_state (struct seq_file *seq, void *offset)
 80 {
 81         struct acpi_fan         *fan = (struct acpi_fan *) seq->private;
 82         int                     state = 0;
 83 
 84         ACPI_FUNCTION_TRACE("acpi_fan_read_state");
 85 
 86         if (!fan)
 87                 goto end;
 88 
 89         if (acpi_bus_get_power(fan->handle, &state))
 90                 goto end;
 91 
 92         seq_printf(seq, "status:                  %s\n",
 93                 !state?"on":"off");
 94 
 95 end:
 96         return_VALUE(0);
 97 }
 98 
 99 static int acpi_fan_state_open_fs(struct inode *inode, struct file *file)
100 {
101         return single_open(file, acpi_fan_read_state, PDE(inode)->data);
102 }
103 
104 static ssize_t
105 acpi_fan_write_state (
106         struct file             *file,
107         const char              __user *buffer,
108         size_t                  count,
109         loff_t                  *ppos)
110 {
111         int                     result = 0;
112         struct seq_file         *m = (struct seq_file *)file->private_data;
113         struct acpi_fan         *fan = (struct acpi_fan *) m->private;
114         char                    state_string[12] = {'\0'};
115 
116         ACPI_FUNCTION_TRACE("acpi_fan_write_state");
117 
118         if (!fan || (count > sizeof(state_string) - 1))
119                 return_VALUE(-EINVAL);
120         
121         if (copy_from_user(state_string, buffer, count))
122                 return_VALUE(-EFAULT);
123         
124         state_string[count] = '\0';
125         
126         result = acpi_bus_set_power(fan->handle, 
127                 simple_strtoul(state_string, NULL, 0));
128         if (result)
129                 return_VALUE(result);
130 
131         return_VALUE(count);
132 }
133 
134 static struct file_operations acpi_fan_state_ops = {
135         .open           = acpi_fan_state_open_fs,
136         .read           = seq_read,
137         .write          = acpi_fan_write_state,
138         .llseek         = seq_lseek,
139         .release        = single_release,
140         .owner = THIS_MODULE,
141 };
142 
143 static int
144 acpi_fan_add_fs (
145         struct acpi_device      *device)
146 {
147         struct proc_dir_entry   *entry = NULL;
148 
149         ACPI_FUNCTION_TRACE("acpi_fan_add_fs");
150 
151         if (!device)
152                 return_VALUE(-EINVAL);
153 
154         if (!acpi_device_dir(device)) {
155                 acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
156                         acpi_fan_dir);
157                 if (!acpi_device_dir(device))
158                         return_VALUE(-ENODEV);
159                 acpi_device_dir(device)->owner = THIS_MODULE;
160         }
161 
162         /* 'status' [R/W] */
163         entry = create_proc_entry(ACPI_FAN_FILE_STATE,
164                 S_IFREG|S_IRUGO|S_IWUSR, acpi_device_dir(device));
165         if (!entry)
166                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
167                         "Unable to create '%s' fs entry\n",
168                         ACPI_FAN_FILE_STATE));
169         else {
170                 entry->proc_fops = &acpi_fan_state_ops;
171                 entry->data = acpi_driver_data(device);
172                 entry->owner = THIS_MODULE;
173         }
174 
175         return_VALUE(0);
176 }
177 
178 
179 static int
180 acpi_fan_remove_fs (
181         struct acpi_device      *device)
182 {
183         ACPI_FUNCTION_TRACE("acpi_fan_remove_fs");
184 
185         if (acpi_device_dir(device)) {
186                 remove_proc_entry(ACPI_FAN_FILE_STATE,
187                                   acpi_device_dir(device));
188                 remove_proc_entry(acpi_device_bid(device), acpi_fan_dir);
189                 acpi_device_dir(device) = NULL;
190         }
191 
192         return_VALUE(0);
193 }
194 
195 
196 /* --------------------------------------------------------------------------
197                                  Driver Interface
198    -------------------------------------------------------------------------- */
199 
200 int
201 acpi_fan_add (
202         struct acpi_device      *device)
203 {
204         int                     result = 0;
205         struct acpi_fan         *fan = NULL;
206         int                     state = 0;
207 
208         ACPI_FUNCTION_TRACE("acpi_fan_add");
209 
210         if (!device)
211                 return_VALUE(-EINVAL);
212 
213         fan = kmalloc(sizeof(struct acpi_fan), GFP_KERNEL);
214         if (!fan)
215                 return_VALUE(-ENOMEM);
216         memset(fan, 0, sizeof(struct acpi_fan));
217 
218         fan->handle = device->handle;
219         strcpy(acpi_device_name(device), ACPI_FAN_DEVICE_NAME);
220         strcpy(acpi_device_class(device), ACPI_FAN_CLASS);
221         acpi_driver_data(device) = fan;
222 
223         result = acpi_bus_get_power(fan->handle, &state);
224         if (result) {
225                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
226                         "Error reading power state\n"));
227                 goto end;
228         }
229 
230         result = acpi_fan_add_fs(device);
231         if (result)
232                 goto end;
233 
234         printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
235                 acpi_device_name(device), acpi_device_bid(device),
236                 !device->power.state?"on":"off");
237 
238 end:
239         if (result)
240                 kfree(fan);
241 
242         return_VALUE(result);
243 }
244 
245 
246 int
247 acpi_fan_remove (
248         struct acpi_device      *device,
249         int                     type)
250 {
251         struct acpi_fan         *fan = NULL;
252 
253         ACPI_FUNCTION_TRACE("acpi_fan_remove");
254 
255         if (!device || !acpi_driver_data(device))
256                 return_VALUE(-EINVAL);
257 
258         fan = (struct acpi_fan *) acpi_driver_data(device);
259 
260         acpi_fan_remove_fs(device);
261 
262         kfree(fan);
263 
264         return_VALUE(0);
265 }
266 
267 
268 int __init
269 acpi_fan_init (void)
270 {
271         int                     result = 0;
272 
273         ACPI_FUNCTION_TRACE("acpi_fan_init");
274 
275         acpi_fan_dir = proc_mkdir(ACPI_FAN_CLASS, acpi_root_dir);
276         if (!acpi_fan_dir)
277                 return_VALUE(-ENODEV);
278         acpi_fan_dir->owner = THIS_MODULE;
279 
280         result = acpi_bus_register_driver(&acpi_fan_driver);
281         if (result < 0) {
282                 remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
283                 return_VALUE(-ENODEV);
284         }
285 
286         return_VALUE(0);
287 }
288 
289 
290 void __exit
291 acpi_fan_exit (void)
292 {
293         ACPI_FUNCTION_TRACE("acpi_fan_exit");
294 
295         acpi_bus_unregister_driver(&acpi_fan_driver);
296 
297         remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
298 
299         return_VOID;
300 }
301 
302 
303 module_init(acpi_fan_init);
304 module_exit(acpi_fan_exit);
305 
306 
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