File: /usr/src/linux/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/config.h>
6 #include <linux/module.h>
7 #include <linux/sched.h>
8 #include <linux/miscdevice.h>
9 #include <linux/smp_lock.h>
10 #include <linux/delay.h>
11 #include <linux/proc_fs.h>
12 #include <linux/capability.h>
13 #include <linux/init.h>
14
15 #include <asm/hardware.h>
16 #include <asm/mach-types.h>
17 #include <asm/uaccess.h>
18 #include <asm/therm.h>
19
20 #ifdef CONFIG_PROC_FS
21 /* define for /proc interface */
22 #define THERM_USE_PROC
23 #endif
24
25 /* Definitions for DS1620 chip */
26 #define THERM_START_CONVERT 0xee
27 #define THERM_RESET 0xaf
28 #define THERM_READ_CONFIG 0xac
29 #define THERM_READ_TEMP 0xaa
30 #define THERM_READ_TL 0xa2
31 #define THERM_READ_TH 0xa1
32 #define THERM_WRITE_CONFIG 0x0c
33 #define THERM_WRITE_TL 0x02
34 #define THERM_WRITE_TH 0x01
35
36 #define CFG_CPU 2
37 #define CFG_1SHOT 1
38
39 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
40
41 /*
42 * Start of NetWinder specifics
43 * Note! We have to hold the gpio lock with IRQs disabled over the
44 * whole of our transaction to the Dallas chip, since there is a
45 * chance that the WaveArtist driver could touch these bits to
46 * enable or disable the speaker.
47 */
48 extern spinlock_t gpio_lock;
49 extern unsigned int system_rev;
50
51 static inline void netwinder_ds1620_set_clk(int clk)
52 {
53 gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54 }
55
56 static inline void netwinder_ds1620_set_data(int dat)
57 {
58 gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59 }
60
61 static inline int netwinder_ds1620_get_data(void)
62 {
63 return gpio_read() & GPIO_DATA;
64 }
65
66 static inline void netwinder_ds1620_set_data_dir(int dir)
67 {
68 gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69 }
70
71 static inline void netwinder_ds1620_reset(void)
72 {
73 cpld_modify(CPLD_DS_ENABLE, 0);
74 cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
75 }
76
77 static inline void netwinder_lock(unsigned long *flags)
78 {
79 spin_lock_irqsave(&gpio_lock, *flags);
80 }
81
82 static inline void netwinder_unlock(unsigned long *flags)
83 {
84 spin_unlock_irqrestore(&gpio_lock, *flags);
85 }
86
87 static inline void netwinder_set_fan(int i)
88 {
89 unsigned long flags;
90
91 spin_lock_irqsave(&gpio_lock, flags);
92 gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
93 spin_unlock_irqrestore(&gpio_lock, flags);
94 }
95
96 static inline int netwinder_get_fan(void)
97 {
98 if ((system_rev & 0xf000) == 0x4000)
99 return FAN_ALWAYS_ON;
100
101 return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
102 }
103
104 /*
105 * End of NetWinder specifics
106 */
107
108 static void ds1620_send_bits(int nr, int value)
109 {
110 int i;
111
112 for (i = 0; i < nr; i++) {
113 netwinder_ds1620_set_data(value & 1);
114 netwinder_ds1620_set_clk(0);
115 udelay(1);
116 netwinder_ds1620_set_clk(1);
117 udelay(1);
118
119 value >>= 1;
120 }
121 }
122
123 static unsigned int ds1620_recv_bits(int nr)
124 {
125 unsigned int value = 0, mask = 1;
126 int i;
127
128 netwinder_ds1620_set_data(0);
129
130 for (i = 0; i < nr; i++) {
131 netwinder_ds1620_set_clk(0);
132 udelay(1);
133
134 if (netwinder_ds1620_get_data())
135 value |= mask;
136
137 mask <<= 1;
138
139 netwinder_ds1620_set_clk(1);
140 udelay(1);
141 }
142
143 return value;
144 }
145
146 static void ds1620_out(int cmd, int bits, int value)
147 {
148 unsigned long flags;
149
150 netwinder_lock(&flags);
151 netwinder_ds1620_set_clk(1);
152 netwinder_ds1620_set_data_dir(0);
153 netwinder_ds1620_reset();
154
155 udelay(1);
156
157 ds1620_send_bits(8, cmd);
158 if (bits)
159 ds1620_send_bits(bits, value);
160
161 udelay(1);
162
163 netwinder_ds1620_reset();
164 netwinder_unlock(&flags);
165
166 set_current_state(TASK_INTERRUPTIBLE);
167 schedule_timeout(2);
168 }
169
170 static unsigned int ds1620_in(int cmd, int bits)
171 {
172 unsigned long flags;
173 unsigned int value;
174
175 netwinder_lock(&flags);
176 netwinder_ds1620_set_clk(1);
177 netwinder_ds1620_set_data_dir(0);
178 netwinder_ds1620_reset();
179
180 udelay(1);
181
182 ds1620_send_bits(8, cmd);
183
184 netwinder_ds1620_set_data_dir(1);
185 value = ds1620_recv_bits(bits);
186
187 netwinder_ds1620_reset();
188 netwinder_unlock(&flags);
189
190 return value;
191 }
192
193 static int cvt_9_to_int(unsigned int val)
194 {
195 if (val & 0x100)
196 val |= 0xfffffe00;
197
198 return val;
199 }
200
201 static void ds1620_write_state(struct therm *therm)
202 {
203 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
204 ds1620_out(THERM_WRITE_TL, 9, therm->lo);
205 ds1620_out(THERM_WRITE_TH, 9, therm->hi);
206 ds1620_out(THERM_START_CONVERT, 0, 0);
207 }
208
209 static void ds1620_read_state(struct therm *therm)
210 {
211 therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
212 therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
213 }
214
215 static ssize_t
216 ds1620_read(struct file *file, char *buf, size_t count, loff_t *ptr)
217 {
218 signed int cur_temp;
219 signed char cur_temp_degF;
220
221 /* Can't seek (pread) on this device */
222 if (ptr != &file->f_pos)
223 return -ESPIPE;
224
225 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
226
227 /* convert to Fahrenheit, as per wdt.c */
228 cur_temp_degF = (cur_temp * 9) / 5 + 32;
229
230 if (copy_to_user(buf, &cur_temp_degF, 1))
231 return -EFAULT;
232
233 return 1;
234 }
235
236 static int
237 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
238 {
239 struct therm therm;
240 int i;
241
242 switch(cmd) {
243 case CMD_SET_THERMOSTATE:
244 case CMD_SET_THERMOSTATE2:
245 if (!capable(CAP_SYS_ADMIN))
246 return -EPERM;
247
248 if (cmd == CMD_SET_THERMOSTATE) {
249 if (get_user(therm.hi, (int *)arg))
250 return -EFAULT;
251 therm.lo = therm.hi - 3;
252 } else {
253 if (copy_from_user(&therm, (void *)arg, sizeof(therm)))
254 return -EFAULT;
255 }
256
257 therm.lo <<= 1;
258 therm.hi <<= 1;
259
260 ds1620_write_state(&therm);
261 break;
262
263 case CMD_GET_THERMOSTATE:
264 case CMD_GET_THERMOSTATE2:
265 ds1620_read_state(&therm);
266
267 therm.lo >>= 1;
268 therm.hi >>= 1;
269
270 if (cmd == CMD_GET_THERMOSTATE) {
271 if (put_user(therm.hi, (int *)arg))
272 return -EFAULT;
273 } else {
274 if (copy_to_user((void *)arg, &therm, sizeof(therm)))
275 return -EFAULT;
276 }
277 break;
278
279 case CMD_GET_TEMPERATURE:
280 case CMD_GET_TEMPERATURE2:
281 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
282
283 if (cmd == CMD_GET_TEMPERATURE)
284 i >>= 1;
285
286 return put_user(i, (int *)arg) ? -EFAULT : 0;
287
288 case CMD_GET_STATUS:
289 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
290
291 return put_user(i, (int *)arg) ? -EFAULT : 0;
292
293 case CMD_GET_FAN:
294 i = netwinder_get_fan();
295
296 return put_user(i, (int *)arg) ? -EFAULT : 0;
297
298 case CMD_SET_FAN:
299 if (!capable(CAP_SYS_ADMIN))
300 return -EPERM;
301
302 if (get_user(i, (int *)arg))
303 return -EFAULT;
304
305 netwinder_set_fan(i);
306 break;
307
308 default:
309 return -ENOIOCTLCMD;
310 }
311
312 return 0;
313 }
314
315 #ifdef THERM_USE_PROC
316 static int
317 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
318 int len, int *eof, void *unused)
319 {
320 struct therm th;
321 int temp;
322
323 ds1620_read_state(&th);
324 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
325
326 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
327 "temperature: %i.%i C, fan %s\n",
328 th.hi >> 1, th.hi & 1 ? 5 : 0,
329 th.lo >> 1, th.lo & 1 ? 5 : 0,
330 temp >> 1, temp & 1 ? 5 : 0,
331 fan_state[netwinder_get_fan()]);
332
333 return len;
334 }
335
336 static struct proc_dir_entry *proc_therm_ds1620;
337 #endif
338
339 static struct file_operations ds1620_fops = {
340 owner: THIS_MODULE,
341 read: ds1620_read,
342 ioctl: ds1620_ioctl,
343 };
344
345 static struct miscdevice ds1620_miscdev = {
346 TEMP_MINOR,
347 "temp",
348 &ds1620_fops
349 };
350
351 int __init ds1620_init(void)
352 {
353 int ret;
354 struct therm th, th_start;
355
356 if (!machine_is_netwinder())
357 return -ENODEV;
358
359 ds1620_out(THERM_RESET, 0, 0);
360 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
361 ds1620_out(THERM_START_CONVERT, 0, 0);
362
363 /*
364 * Trigger the fan to start by setting
365 * temperature high point low. This kicks
366 * the fan into action.
367 */
368 ds1620_read_state(&th);
369 th_start.lo = 0;
370 th_start.hi = 1;
371 ds1620_write_state(&th_start);
372
373 set_current_state(TASK_INTERRUPTIBLE);
374 schedule_timeout(2*HZ);
375
376 ds1620_write_state(&th);
377
378 ret = misc_register(&ds1620_miscdev);
379 if (ret < 0)
380 return ret;
381
382 #ifdef THERM_USE_PROC
383 proc_therm_ds1620 = create_proc_entry("therm", 0, 0);
384 if (proc_therm_ds1620)
385 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
386 else
387 printk(KERN_ERR "therm: unable to register /proc/therm\n");
388 #endif
389
390 ds1620_read_state(&th);
391 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
392
393 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
394 "current %i.%i C, fan %s.\n",
395 th.hi >> 1, th.hi & 1 ? 5 : 0,
396 th.lo >> 1, th.lo & 1 ? 5 : 0,
397 ret >> 1, ret & 1 ? 5 : 0,
398 fan_state[netwinder_get_fan()]);
399
400 return 0;
401 }
402
403 void __exit ds1620_exit(void)
404 {
405 #ifdef THERM_USE_PROC
406 remove_proc_entry("therm", NULL);
407 #endif
408 misc_deregister(&ds1620_miscdev);
409 }
410
411 module_init(ds1620_init);
412 module_exit(ds1620_exit);
413
414 MODULE_LICENSE("GPL");
415