llseek: automatically add .llseek fop
[linux-2.6.git] / drivers / char / ds1620.c
1 /*
2  * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
3  *   thermometer driver (as used in the Rebel.com NetWinder)
4  */
5 #include <linux/module.h>
6 #include <linux/miscdevice.h>
7 #include <linux/delay.h>
8 #include <linux/proc_fs.h>
9 #include <linux/capability.h>
10 #include <linux/init.h>
11 #include <linux/smp_lock.h>
12
13 #include <mach/hardware.h>
14 #include <asm/mach-types.h>
15 #include <asm/uaccess.h>
16 #include <asm/therm.h>
17
18 #ifdef CONFIG_PROC_FS
19 /* define for /proc interface */
20 #define THERM_USE_PROC
21 #endif
22
23 /* Definitions for DS1620 chip */
24 #define THERM_START_CONVERT     0xee
25 #define THERM_RESET             0xaf
26 #define THERM_READ_CONFIG       0xac
27 #define THERM_READ_TEMP         0xaa
28 #define THERM_READ_TL           0xa2
29 #define THERM_READ_TH           0xa1
30 #define THERM_WRITE_CONFIG      0x0c
31 #define THERM_WRITE_TL          0x02
32 #define THERM_WRITE_TH          0x01
33
34 #define CFG_CPU                 2
35 #define CFG_1SHOT               1
36
37 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
38
39 /*
40  * Start of NetWinder specifics
41  *  Note!  We have to hold the gpio lock with IRQs disabled over the
42  *  whole of our transaction to the Dallas chip, since there is a
43  *  chance that the WaveArtist driver could touch these bits to
44  *  enable or disable the speaker.
45  */
46 extern unsigned int system_rev;
47
48 static inline void netwinder_ds1620_set_clk(int clk)
49 {
50         nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
51 }
52
53 static inline void netwinder_ds1620_set_data(int dat)
54 {
55         nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
56 }
57
58 static inline int netwinder_ds1620_get_data(void)
59 {
60         return nw_gpio_read() & GPIO_DATA;
61 }
62
63 static inline void netwinder_ds1620_set_data_dir(int dir)
64 {
65         nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
66 }
67
68 static inline void netwinder_ds1620_reset(void)
69 {
70         nw_cpld_modify(CPLD_DS_ENABLE, 0);
71         nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
72 }
73
74 static inline void netwinder_lock(unsigned long *flags)
75 {
76         spin_lock_irqsave(&nw_gpio_lock, *flags);
77 }
78
79 static inline void netwinder_unlock(unsigned long *flags)
80 {
81         spin_unlock_irqrestore(&nw_gpio_lock, *flags);
82 }
83
84 static inline void netwinder_set_fan(int i)
85 {
86         unsigned long flags;
87
88         spin_lock_irqsave(&nw_gpio_lock, flags);
89         nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
90         spin_unlock_irqrestore(&nw_gpio_lock, flags);
91 }
92
93 static inline int netwinder_get_fan(void)
94 {
95         if ((system_rev & 0xf000) == 0x4000)
96                 return FAN_ALWAYS_ON;
97
98         return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
99 }
100
101 /*
102  * End of NetWinder specifics
103  */
104
105 static void ds1620_send_bits(int nr, int value)
106 {
107         int i;
108
109         for (i = 0; i < nr; i++) {
110                 netwinder_ds1620_set_data(value & 1);
111                 netwinder_ds1620_set_clk(0);
112                 udelay(1);
113                 netwinder_ds1620_set_clk(1);
114                 udelay(1);
115
116                 value >>= 1;
117         }
118 }
119
120 static unsigned int ds1620_recv_bits(int nr)
121 {
122         unsigned int value = 0, mask = 1;
123         int i;
124
125         netwinder_ds1620_set_data(0);
126
127         for (i = 0; i < nr; i++) {
128                 netwinder_ds1620_set_clk(0);
129                 udelay(1);
130
131                 if (netwinder_ds1620_get_data())
132                         value |= mask;
133
134                 mask <<= 1;
135
136                 netwinder_ds1620_set_clk(1);
137                 udelay(1);
138         }
139
140         return value;
141 }
142
143 static void ds1620_out(int cmd, int bits, int value)
144 {
145         unsigned long flags;
146
147         netwinder_lock(&flags);
148         netwinder_ds1620_set_clk(1);
149         netwinder_ds1620_set_data_dir(0);
150         netwinder_ds1620_reset();
151
152         udelay(1);
153
154         ds1620_send_bits(8, cmd);
155         if (bits)
156                 ds1620_send_bits(bits, value);
157
158         udelay(1);
159
160         netwinder_ds1620_reset();
161         netwinder_unlock(&flags);
162
163         msleep(20);
164 }
165
166 static unsigned int ds1620_in(int cmd, int bits)
167 {
168         unsigned long flags;
169         unsigned int value;
170
171         netwinder_lock(&flags);
172         netwinder_ds1620_set_clk(1);
173         netwinder_ds1620_set_data_dir(0);
174         netwinder_ds1620_reset();
175
176         udelay(1);
177
178         ds1620_send_bits(8, cmd);
179
180         netwinder_ds1620_set_data_dir(1);
181         value = ds1620_recv_bits(bits);
182
183         netwinder_ds1620_reset();
184         netwinder_unlock(&flags);
185
186         return value;
187 }
188
189 static int cvt_9_to_int(unsigned int val)
190 {
191         if (val & 0x100)
192                 val |= 0xfffffe00;
193
194         return val;
195 }
196
197 static void ds1620_write_state(struct therm *therm)
198 {
199         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
200         ds1620_out(THERM_WRITE_TL, 9, therm->lo);
201         ds1620_out(THERM_WRITE_TH, 9, therm->hi);
202         ds1620_out(THERM_START_CONVERT, 0, 0);
203 }
204
205 static void ds1620_read_state(struct therm *therm)
206 {
207         therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
208         therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
209 }
210
211 static int ds1620_open(struct inode *inode, struct file *file)
212 {
213         cycle_kernel_lock();
214         return nonseekable_open(inode, file);
215 }
216
217 static ssize_t
218 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
219 {
220         signed int cur_temp;
221         signed char cur_temp_degF;
222
223         cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
224
225         /* convert to Fahrenheit, as per wdt.c */
226         cur_temp_degF = (cur_temp * 9) / 5 + 32;
227
228         if (copy_to_user(buf, &cur_temp_degF, 1))
229                 return -EFAULT;
230
231         return 1;
232 }
233
234 static int
235 ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
236 {
237         struct therm therm;
238         union {
239                 struct therm __user *therm;
240                 int __user *i;
241         } uarg;
242         int i;
243
244         uarg.i = (int __user *)arg;
245
246         switch(cmd) {
247         case CMD_SET_THERMOSTATE:
248         case CMD_SET_THERMOSTATE2:
249                 if (!capable(CAP_SYS_ADMIN))
250                         return -EPERM;
251
252                 if (cmd == CMD_SET_THERMOSTATE) {
253                         if (get_user(therm.hi, uarg.i))
254                                 return -EFAULT;
255                         therm.lo = therm.hi - 3;
256                 } else {
257                         if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
258                                 return -EFAULT;
259                 }
260
261                 therm.lo <<= 1;
262                 therm.hi <<= 1;
263
264                 ds1620_write_state(&therm);
265                 break;
266
267         case CMD_GET_THERMOSTATE:
268         case CMD_GET_THERMOSTATE2:
269                 ds1620_read_state(&therm);
270
271                 therm.lo >>= 1;
272                 therm.hi >>= 1;
273
274                 if (cmd == CMD_GET_THERMOSTATE) {
275                         if (put_user(therm.hi, uarg.i))
276                                 return -EFAULT;
277                 } else {
278                         if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
279                                 return -EFAULT;
280                 }
281                 break;
282
283         case CMD_GET_TEMPERATURE:
284         case CMD_GET_TEMPERATURE2:
285                 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
286
287                 if (cmd == CMD_GET_TEMPERATURE)
288                         i >>= 1;
289
290                 return put_user(i, uarg.i) ? -EFAULT : 0;
291
292         case CMD_GET_STATUS:
293                 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
294
295                 return put_user(i, uarg.i) ? -EFAULT : 0;
296
297         case CMD_GET_FAN:
298                 i = netwinder_get_fan();
299
300                 return put_user(i, uarg.i) ? -EFAULT : 0;
301
302         case CMD_SET_FAN:
303                 if (!capable(CAP_SYS_ADMIN))
304                         return -EPERM;
305
306                 if (get_user(i, uarg.i))
307                         return -EFAULT;
308
309                 netwinder_set_fan(i);
310                 break;
311                 
312         default:
313                 return -ENOIOCTLCMD;
314         }
315
316         return 0;
317 }
318
319 static long
320 ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
321 {
322         int ret;
323
324         lock_kernel();
325         ret = ds1620_ioctl(file, cmd, arg);
326         unlock_kernel();
327
328         return ret;
329 }
330
331 #ifdef THERM_USE_PROC
332 static int
333 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
334                        int len, int *eof, void *unused)
335 {
336         struct therm th;
337         int temp;
338
339         ds1620_read_state(&th);
340         temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
341
342         len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
343                       "temperature: %i.%i C, fan %s\n",
344                       th.hi >> 1, th.hi & 1 ? 5 : 0,
345                       th.lo >> 1, th.lo & 1 ? 5 : 0,
346                       temp  >> 1, temp  & 1 ? 5 : 0,
347                       fan_state[netwinder_get_fan()]);
348
349         return len;
350 }
351
352 static struct proc_dir_entry *proc_therm_ds1620;
353 #endif
354
355 static const struct file_operations ds1620_fops = {
356         .owner          = THIS_MODULE,
357         .open           = ds1620_open,
358         .read           = ds1620_read,
359         .unlocked_ioctl = ds1620_unlocked_ioctl,
360         .llseek         = no_llseek,
361 };
362
363 static struct miscdevice ds1620_miscdev = {
364         TEMP_MINOR,
365         "temp",
366         &ds1620_fops
367 };
368
369 static int __init ds1620_init(void)
370 {
371         int ret;
372         struct therm th, th_start;
373
374         if (!machine_is_netwinder())
375                 return -ENODEV;
376
377         ds1620_out(THERM_RESET, 0, 0);
378         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
379         ds1620_out(THERM_START_CONVERT, 0, 0);
380
381         /*
382          * Trigger the fan to start by setting
383          * temperature high point low.  This kicks
384          * the fan into action.
385          */
386         ds1620_read_state(&th);
387         th_start.lo = 0;
388         th_start.hi = 1;
389         ds1620_write_state(&th_start);
390
391         msleep(2000);
392
393         ds1620_write_state(&th);
394
395         ret = misc_register(&ds1620_miscdev);
396         if (ret < 0)
397                 return ret;
398
399 #ifdef THERM_USE_PROC
400         proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
401         if (proc_therm_ds1620)
402                 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
403         else
404                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
405 #endif
406
407         ds1620_read_state(&th);
408         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
409
410         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
411                "current %i.%i C, fan %s.\n",
412                th.hi >> 1, th.hi & 1 ? 5 : 0,
413                th.lo >> 1, th.lo & 1 ? 5 : 0,
414                ret   >> 1, ret   & 1 ? 5 : 0,
415                fan_state[netwinder_get_fan()]);
416
417         return 0;
418 }
419
420 static void __exit ds1620_exit(void)
421 {
422 #ifdef THERM_USE_PROC
423         remove_proc_entry("therm", NULL);
424 #endif
425         misc_deregister(&ds1620_miscdev);
426 }
427
428 module_init(ds1620_init);
429 module_exit(ds1620_exit);
430
431 MODULE_LICENSE("GPL");