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/mutex.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 DEFINE_MUTEX(ds1620_mutex);
38 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
39
40 /*
41 * Start of NetWinder specifics
42 * Note! We have to hold the gpio lock with IRQs disabled over the
43 * whole of our transaction to the Dallas chip, since there is a
44 * chance that the WaveArtist driver could touch these bits to
45 * enable or disable the speaker.
46 */
47 extern unsigned int system_rev;
48
netwinder_ds1620_set_clk(int clk)49 static inline void netwinder_ds1620_set_clk(int clk)
50 {
51 nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
52 }
53
netwinder_ds1620_set_data(int dat)54 static inline void netwinder_ds1620_set_data(int dat)
55 {
56 nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
57 }
58
netwinder_ds1620_get_data(void)59 static inline int netwinder_ds1620_get_data(void)
60 {
61 return nw_gpio_read() & GPIO_DATA;
62 }
63
netwinder_ds1620_set_data_dir(int dir)64 static inline void netwinder_ds1620_set_data_dir(int dir)
65 {
66 nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
67 }
68
netwinder_ds1620_reset(void)69 static inline void netwinder_ds1620_reset(void)
70 {
71 nw_cpld_modify(CPLD_DS_ENABLE, 0);
72 nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
73 }
74
netwinder_lock(unsigned long * flags)75 static inline void netwinder_lock(unsigned long *flags)
76 {
77 spin_lock_irqsave(&nw_gpio_lock, *flags);
78 }
79
netwinder_unlock(unsigned long * flags)80 static inline void netwinder_unlock(unsigned long *flags)
81 {
82 spin_unlock_irqrestore(&nw_gpio_lock, *flags);
83 }
84
netwinder_set_fan(int i)85 static inline void netwinder_set_fan(int i)
86 {
87 unsigned long flags;
88
89 spin_lock_irqsave(&nw_gpio_lock, flags);
90 nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
91 spin_unlock_irqrestore(&nw_gpio_lock, flags);
92 }
93
netwinder_get_fan(void)94 static inline int netwinder_get_fan(void)
95 {
96 if ((system_rev & 0xf000) == 0x4000)
97 return FAN_ALWAYS_ON;
98
99 return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
100 }
101
102 /*
103 * End of NetWinder specifics
104 */
105
ds1620_send_bits(int nr,int value)106 static void ds1620_send_bits(int nr, int value)
107 {
108 int i;
109
110 for (i = 0; i < nr; i++) {
111 netwinder_ds1620_set_data(value & 1);
112 netwinder_ds1620_set_clk(0);
113 udelay(1);
114 netwinder_ds1620_set_clk(1);
115 udelay(1);
116
117 value >>= 1;
118 }
119 }
120
ds1620_recv_bits(int nr)121 static unsigned int ds1620_recv_bits(int nr)
122 {
123 unsigned int value = 0, mask = 1;
124 int i;
125
126 netwinder_ds1620_set_data(0);
127
128 for (i = 0; i < nr; i++) {
129 netwinder_ds1620_set_clk(0);
130 udelay(1);
131
132 if (netwinder_ds1620_get_data())
133 value |= mask;
134
135 mask <<= 1;
136
137 netwinder_ds1620_set_clk(1);
138 udelay(1);
139 }
140
141 return value;
142 }
143
ds1620_out(int cmd,int bits,int value)144 static void ds1620_out(int cmd, int bits, int value)
145 {
146 unsigned long flags;
147
148 netwinder_lock(&flags);
149 netwinder_ds1620_set_clk(1);
150 netwinder_ds1620_set_data_dir(0);
151 netwinder_ds1620_reset();
152
153 udelay(1);
154
155 ds1620_send_bits(8, cmd);
156 if (bits)
157 ds1620_send_bits(bits, value);
158
159 udelay(1);
160
161 netwinder_ds1620_reset();
162 netwinder_unlock(&flags);
163
164 msleep(20);
165 }
166
ds1620_in(int cmd,int bits)167 static unsigned int ds1620_in(int cmd, int bits)
168 {
169 unsigned long flags;
170 unsigned int value;
171
172 netwinder_lock(&flags);
173 netwinder_ds1620_set_clk(1);
174 netwinder_ds1620_set_data_dir(0);
175 netwinder_ds1620_reset();
176
177 udelay(1);
178
179 ds1620_send_bits(8, cmd);
180
181 netwinder_ds1620_set_data_dir(1);
182 value = ds1620_recv_bits(bits);
183
184 netwinder_ds1620_reset();
185 netwinder_unlock(&flags);
186
187 return value;
188 }
189
cvt_9_to_int(unsigned int val)190 static int cvt_9_to_int(unsigned int val)
191 {
192 if (val & 0x100)
193 val |= 0xfffffe00;
194
195 return val;
196 }
197
ds1620_write_state(struct therm * therm)198 static void ds1620_write_state(struct therm *therm)
199 {
200 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
201 ds1620_out(THERM_WRITE_TL, 9, therm->lo);
202 ds1620_out(THERM_WRITE_TH, 9, therm->hi);
203 ds1620_out(THERM_START_CONVERT, 0, 0);
204 }
205
ds1620_read_state(struct therm * therm)206 static void ds1620_read_state(struct therm *therm)
207 {
208 therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
209 therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
210 }
211
ds1620_open(struct inode * inode,struct file * file)212 static int ds1620_open(struct inode *inode, struct file *file)
213 {
214 return nonseekable_open(inode, file);
215 }
216
217 static ssize_t
ds1620_read(struct file * file,char __user * buf,size_t count,loff_t * ptr)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
ds1620_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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
ds1620_unlocked_ioctl(struct file * file,unsigned int cmd,unsigned long arg)320 ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
321 {
322 int ret;
323
324 mutex_lock(&ds1620_mutex);
325 ret = ds1620_ioctl(file, cmd, arg);
326 mutex_unlock(&ds1620_mutex);
327
328 return ret;
329 }
330
331 #ifdef THERM_USE_PROC
332 static int
proc_therm_ds1620_read(char * buf,char ** start,off_t offset,int len,int * eof,void * unused)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
ds1620_init(void)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
ds1620_exit(void)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");
432