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  *  Driver for TANBAC TB0219 base board.
  3  *
  4  *  Copyright (C) 2005  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
  5  *
  6  *  This program is free software; you can redistribute it and/or modify
  7  *  it under the terms of the GNU General Public License as published by
  8  *  the Free Software Foundation; either version 2 of the License, or
  9  *  (at your option) any later version.
 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  *  You should have received a copy of the GNU General Public License
 17  *  along with this program; if not, write to the Free Software
 18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 19  */
 20 #include <linux/platform_device.h>
 21 #include <linux/fs.h>
 22 #include <linux/init.h>
 23 #include <linux/module.h>
 24 
 25 #include <asm/io.h>
 26 #include <asm/reboot.h>
 27 #include <asm/vr41xx/giu.h>
 28 #include <asm/vr41xx/tb0219.h>
 29 
 30 MODULE_AUTHOR("Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>");
 31 MODULE_DESCRIPTION("TANBAC TB0219 base board driver");
 32 MODULE_LICENSE("GPL");
 33 
 34 static int major;       /* default is dynamic major device number */
 35 module_param(major, int, 0);
 36 MODULE_PARM_DESC(major, "Major device number");
 37 
 38 static void (*old_machine_restart)(char *command);
 39 static void __iomem *tb0219_base;
 40 static spinlock_t tb0219_lock;
 41 
 42 #define tb0219_read(offset)             readw(tb0219_base + (offset))
 43 #define tb0219_write(offset, value)     writew((value), tb0219_base + (offset))
 44 
 45 #define TB0219_START    0x0a000000UL
 46 #define TB0219_SIZE     0x20UL
 47 
 48 #define TB0219_LED                      0x00
 49 #define TB0219_GPIO_INPUT               0x02
 50 #define TB0219_GPIO_OUTPUT              0x04
 51 #define TB0219_DIP_SWITCH               0x06
 52 #define TB0219_MISC                     0x08
 53 #define TB0219_RESET                    0x0e
 54 #define TB0219_PCI_SLOT1_IRQ_STATUS     0x10
 55 #define TB0219_PCI_SLOT2_IRQ_STATUS     0x12
 56 #define TB0219_PCI_SLOT3_IRQ_STATUS     0x14
 57 
 58 typedef enum {
 59         TYPE_LED,
 60         TYPE_GPIO_OUTPUT,
 61 } tb0219_type_t;
 62 
 63 /*
 64  * Minor device number
 65  *       0 = 7 segment LED
 66  *
 67  *      16 = GPIO IN 0
 68  *      17 = GPIO IN 1
 69  *      18 = GPIO IN 2
 70  *      19 = GPIO IN 3
 71  *      20 = GPIO IN 4
 72  *      21 = GPIO IN 5
 73  *      22 = GPIO IN 6
 74  *      23 = GPIO IN 7
 75  *
 76  *      32 = GPIO OUT 0
 77  *      33 = GPIO OUT 1
 78  *      34 = GPIO OUT 2
 79  *      35 = GPIO OUT 3
 80  *      36 = GPIO OUT 4
 81  *      37 = GPIO OUT 5
 82  *      38 = GPIO OUT 6
 83  *      39 = GPIO OUT 7
 84  *
 85  *      48 = DIP switch 1
 86  *      49 = DIP switch 2
 87  *      50 = DIP switch 3
 88  *      51 = DIP switch 4
 89  *      52 = DIP switch 5
 90  *      53 = DIP switch 6
 91  *      54 = DIP switch 7
 92  *      55 = DIP switch 8
 93  */
 94 
 95 static inline char get_led(void)
 96 {
 97         return (char)tb0219_read(TB0219_LED);
 98 }
 99 
100 static inline char get_gpio_input_pin(unsigned int pin)
101 {
102         uint16_t values;
103 
104         values = tb0219_read(TB0219_GPIO_INPUT);
105         if (values & (1 << pin))
106                 return '1';
107 
108         return '';
109 }
110 
111 static inline char get_gpio_output_pin(unsigned int pin)
112 {
113         uint16_t values;
114 
115         values = tb0219_read(TB0219_GPIO_OUTPUT);
116         if (values & (1 << pin))
117                 return '1';
118 
119         return '';
120 }
121 
122 static inline char get_dip_switch(unsigned int pin)
123 {
124         uint16_t values;
125 
126         values = tb0219_read(TB0219_DIP_SWITCH);
127         if (values & (1 << pin))
128                 return '1';
129 
130         return '';
131 }
132 
133 static inline int set_led(char command)
134 {
135         tb0219_write(TB0219_LED, command);
136 
137         return 0;
138 }
139 
140 static inline int set_gpio_output_pin(unsigned int pin, char command)
141 {
142         unsigned long flags;
143         uint16_t value;
144 
145         if (command != '' && command != '1')
146                 return -EINVAL;
147 
148         spin_lock_irqsave(&tb0219_lock, flags);
149         value = tb0219_read(TB0219_GPIO_OUTPUT);
150         if (command == '')
151                 value &= ~(1 << pin);
152         else
153                 value |= 1 << pin;
154         tb0219_write(TB0219_GPIO_OUTPUT, value);
155         spin_unlock_irqrestore(&tb0219_lock, flags);
156 
157         return 0;
158 
159 }
160 
161 static ssize_t tanbac_tb0219_read(struct file *file, char __user *buf, size_t len,
162                                   loff_t *ppos)
163 {
164         unsigned int minor;
165         char value;
166 
167         minor = iminor(file->f_path.dentry->d_inode);
168         switch (minor) {
169         case 0:
170                 value = get_led();
171                 break;
172         case 16 ... 23:
173                 value = get_gpio_input_pin(minor - 16);
174                 break;
175         case 32 ... 39:
176                 value = get_gpio_output_pin(minor - 32);
177                 break;
178         case 48 ... 55:
179                 value = get_dip_switch(minor - 48);
180                 break;
181         default:
182                 return -EBADF;
183         }
184 
185         if (len <= 0)
186                 return -EFAULT;
187 
188         if (put_user(value, buf))
189                 return -EFAULT;
190 
191         return 1;
192 }
193 
194 static ssize_t tanbac_tb0219_write(struct file *file, const char __user *data,
195                                    size_t len, loff_t *ppos)
196 {
197         unsigned int minor;
198         tb0219_type_t type;
199         size_t i;
200         int retval = 0;
201         char c;
202 
203         minor = iminor(file->f_path.dentry->d_inode);
204         switch (minor) {
205         case 0:
206                 type = TYPE_LED;
207                 break;
208         case 32 ... 39:
209                 type = TYPE_GPIO_OUTPUT;
210                 break;
211         default:
212                 return -EBADF;
213         }
214 
215         for (i = 0; i < len; i++) {
216                 if (get_user(c, data + i))
217                         return -EFAULT;
218 
219                 switch (type) {
220                 case TYPE_LED:
221                         retval = set_led(c);
222                         break;
223                 case TYPE_GPIO_OUTPUT:
224                         retval = set_gpio_output_pin(minor - 32, c);
225                         break;
226                 }
227 
228                 if (retval < 0)
229                         break;
230         }
231 
232         return i;
233 }
234 
235 static int tanbac_tb0219_open(struct inode *inode, struct file *file)
236 {
237         unsigned int minor;
238 
239         minor = iminor(inode);
240         switch (minor) {
241         case 0:
242         case 16 ... 23:
243         case 32 ... 39:
244         case 48 ... 55:
245                 return nonseekable_open(inode, file);
246         default:
247                 break;
248         }
249 
250         return -EBADF;
251 }
252 
253 static int tanbac_tb0219_release(struct inode *inode, struct file *file)
254 {
255         return 0;
256 }
257 
258 static const struct file_operations tb0219_fops = {
259         .owner          = THIS_MODULE,
260         .read           = tanbac_tb0219_read,
261         .write          = tanbac_tb0219_write,
262         .open           = tanbac_tb0219_open,
263         .release        = tanbac_tb0219_release,
264 };
265 
266 static void tb0219_restart(char *command)
267 {
268         tb0219_write(TB0219_RESET, 0);
269 }
270 
271 static void tb0219_pci_irq_init(void)
272 {
273         /* PCI Slot 1 */
274         vr41xx_set_irq_trigger(TB0219_PCI_SLOT1_PIN, IRQ_TRIGGER_LEVEL, IRQ_SIGNAL_THROUGH);
275         vr41xx_set_irq_level(TB0219_PCI_SLOT1_PIN, IRQ_LEVEL_LOW);
276 
277         /* PCI Slot 2 */
278         vr41xx_set_irq_trigger(TB0219_PCI_SLOT2_PIN, IRQ_TRIGGER_LEVEL, IRQ_SIGNAL_THROUGH);
279         vr41xx_set_irq_level(TB0219_PCI_SLOT2_PIN, IRQ_LEVEL_LOW);
280 
281         /* PCI Slot 3 */
282         vr41xx_set_irq_trigger(TB0219_PCI_SLOT3_PIN, IRQ_TRIGGER_LEVEL, IRQ_SIGNAL_THROUGH);
283         vr41xx_set_irq_level(TB0219_PCI_SLOT3_PIN, IRQ_LEVEL_LOW);
284 }
285 
286 static int __devinit tb0219_probe(struct platform_device *dev)
287 {
288         int retval;
289 
290         if (request_mem_region(TB0219_START, TB0219_SIZE, "TB0219") == NULL)
291                 return -EBUSY;
292 
293         tb0219_base = ioremap(TB0219_START, TB0219_SIZE);
294         if (tb0219_base == NULL) {
295                 release_mem_region(TB0219_START, TB0219_SIZE);
296                 return -ENOMEM;
297         }
298 
299         retval = register_chrdev(major, "TB0219", &tb0219_fops);
300         if (retval < 0) {
301                 iounmap(tb0219_base);
302                 tb0219_base = NULL;
303                 release_mem_region(TB0219_START, TB0219_SIZE);
304                 return retval;
305         }
306 
307         spin_lock_init(&tb0219_lock);
308 
309         old_machine_restart = _machine_restart;
310         _machine_restart = tb0219_restart;
311 
312         tb0219_pci_irq_init();
313 
314         if (major == 0) {
315                 major = retval;
316                 printk(KERN_INFO "TB0219: major number %d\n", major);
317         }
318 
319         return 0;
320 }
321 
322 static int __devexit tb0219_remove(struct platform_device *dev)
323 {
324         _machine_restart = old_machine_restart;
325 
326         iounmap(tb0219_base);
327         tb0219_base = NULL;
328 
329         release_mem_region(TB0219_START, TB0219_SIZE);
330 
331         return 0;
332 }
333 
334 static struct platform_device *tb0219_platform_device;
335 
336 static struct platform_driver tb0219_device_driver = {
337         .probe          = tb0219_probe,
338         .remove         = __devexit_p(tb0219_remove),
339         .driver         = {
340                 .name   = "TB0219",
341                 .owner  = THIS_MODULE,
342         },
343 };
344 
345 static int __init tanbac_tb0219_init(void)
346 {
347         int retval;
348 
349         tb0219_platform_device = platform_device_alloc("TB0219", -1);
350         if (!tb0219_platform_device)
351                 return -ENOMEM;
352 
353         retval = platform_device_add(tb0219_platform_device);
354         if (retval < 0) {
355                 platform_device_put(tb0219_platform_device);
356                 return retval;
357         }
358 
359         retval = platform_driver_register(&tb0219_device_driver);
360         if (retval < 0)
361                 platform_device_unregister(tb0219_platform_device);
362 
363         return retval;
364 }
365 
366 static void __exit tanbac_tb0219_exit(void)
367 {
368         platform_driver_unregister(&tb0219_device_driver);
369         platform_device_unregister(tb0219_platform_device);
370 }
371 
372 module_init(tanbac_tb0219_init);
373 module_exit(tanbac_tb0219_exit);
374 
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