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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
3 * thermometer driver (as used in the Rebel.com NetWinder)
4 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07005#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#include <linux/miscdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/delay.h>
8#include <linux/proc_fs.h>
9#include <linux/capability.h>
10#include <linux/init.h>
Arnd Bergmann080c2222008-05-20 19:15:50 +020011#include <linux/smp_lock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
13#include <asm/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
37static 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 */
46extern spinlock_t gpio_lock;
47extern unsigned int system_rev;
48
49static inline void netwinder_ds1620_set_clk(int clk)
50{
51 gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
52}
53
54static inline void netwinder_ds1620_set_data(int dat)
55{
56 gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
57}
58
59static inline int netwinder_ds1620_get_data(void)
60{
61 return gpio_read() & GPIO_DATA;
62}
63
64static inline void netwinder_ds1620_set_data_dir(int dir)
65{
66 gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
67}
68
69static inline void netwinder_ds1620_reset(void)
70{
71 cpld_modify(CPLD_DS_ENABLE, 0);
72 cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
73}
74
75static inline void netwinder_lock(unsigned long *flags)
76{
77 spin_lock_irqsave(&gpio_lock, *flags);
78}
79
80static inline void netwinder_unlock(unsigned long *flags)
81{
82 spin_unlock_irqrestore(&gpio_lock, *flags);
83}
84
85static inline void netwinder_set_fan(int i)
86{
87 unsigned long flags;
88
89 spin_lock_irqsave(&gpio_lock, flags);
90 gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
91 spin_unlock_irqrestore(&gpio_lock, flags);
92}
93
94static inline int netwinder_get_fan(void)
95{
96 if ((system_rev & 0xf000) == 0x4000)
97 return FAN_ALWAYS_ON;
98
99 return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
100}
101
102/*
103 * End of NetWinder specifics
104 */
105
106static 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
121static 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
144static 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
Domen Puncerd8eddb62005-06-25 14:58:41 -0700164 msleep(20);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165}
166
167static 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
190static int cvt_9_to_int(unsigned int val)
191{
192 if (val & 0x100)
193 val |= 0xfffffe00;
194
195 return val;
196}
197
198static 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
206static 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
Arnd Bergmann080c2222008-05-20 19:15:50 +0200212static int ds1620_open(struct inode *inode, struct file *file)
213{
214 cycle_kernel_lock();
215 return nonseekable_open(inode, file);
216}
217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218static ssize_t
219ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
220{
221 signed int cur_temp;
222 signed char cur_temp_degF;
223
224 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
225
226 /* convert to Fahrenheit, as per wdt.c */
227 cur_temp_degF = (cur_temp * 9) / 5 + 32;
228
229 if (copy_to_user(buf, &cur_temp_degF, 1))
230 return -EFAULT;
231
232 return 1;
233}
234
235static int
236ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
237{
238 struct therm therm;
239 union {
240 struct therm __user *therm;
241 int __user *i;
242 } uarg;
243 int i;
244
245 uarg.i = (int __user *)arg;
246
247 switch(cmd) {
248 case CMD_SET_THERMOSTATE:
249 case CMD_SET_THERMOSTATE2:
250 if (!capable(CAP_SYS_ADMIN))
251 return -EPERM;
252
253 if (cmd == CMD_SET_THERMOSTATE) {
254 if (get_user(therm.hi, uarg.i))
255 return -EFAULT;
256 therm.lo = therm.hi - 3;
257 } else {
258 if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
259 return -EFAULT;
260 }
261
262 therm.lo <<= 1;
263 therm.hi <<= 1;
264
265 ds1620_write_state(&therm);
266 break;
267
268 case CMD_GET_THERMOSTATE:
269 case CMD_GET_THERMOSTATE2:
270 ds1620_read_state(&therm);
271
272 therm.lo >>= 1;
273 therm.hi >>= 1;
274
275 if (cmd == CMD_GET_THERMOSTATE) {
276 if (put_user(therm.hi, uarg.i))
277 return -EFAULT;
278 } else {
279 if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
280 return -EFAULT;
281 }
282 break;
283
284 case CMD_GET_TEMPERATURE:
285 case CMD_GET_TEMPERATURE2:
286 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
287
288 if (cmd == CMD_GET_TEMPERATURE)
289 i >>= 1;
290
291 return put_user(i, uarg.i) ? -EFAULT : 0;
292
293 case CMD_GET_STATUS:
294 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
295
296 return put_user(i, uarg.i) ? -EFAULT : 0;
297
298 case CMD_GET_FAN:
299 i = netwinder_get_fan();
300
301 return put_user(i, uarg.i) ? -EFAULT : 0;
302
303 case CMD_SET_FAN:
304 if (!capable(CAP_SYS_ADMIN))
305 return -EPERM;
306
307 if (get_user(i, uarg.i))
308 return -EFAULT;
309
310 netwinder_set_fan(i);
311 break;
312
313 default:
314 return -ENOIOCTLCMD;
315 }
316
317 return 0;
318}
319
320#ifdef THERM_USE_PROC
321static int
322proc_therm_ds1620_read(char *buf, char **start, off_t offset,
323 int len, int *eof, void *unused)
324{
325 struct therm th;
326 int temp;
327
328 ds1620_read_state(&th);
329 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
330
331 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
332 "temperature: %i.%i C, fan %s\n",
333 th.hi >> 1, th.hi & 1 ? 5 : 0,
334 th.lo >> 1, th.lo & 1 ? 5 : 0,
335 temp >> 1, temp & 1 ? 5 : 0,
336 fan_state[netwinder_get_fan()]);
337
338 return len;
339}
340
341static struct proc_dir_entry *proc_therm_ds1620;
342#endif
343
Arjan van de Ven62322d22006-07-03 00:24:21 -0700344static const struct file_operations ds1620_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 .owner = THIS_MODULE,
Arnd Bergmann080c2222008-05-20 19:15:50 +0200346 .open = ds1620_open,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 .read = ds1620_read,
348 .ioctl = ds1620_ioctl,
349};
350
351static struct miscdevice ds1620_miscdev = {
352 TEMP_MINOR,
353 "temp",
354 &ds1620_fops
355};
356
357static int __init ds1620_init(void)
358{
359 int ret;
360 struct therm th, th_start;
361
362 if (!machine_is_netwinder())
363 return -ENODEV;
364
365 ds1620_out(THERM_RESET, 0, 0);
366 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
367 ds1620_out(THERM_START_CONVERT, 0, 0);
368
369 /*
370 * Trigger the fan to start by setting
371 * temperature high point low. This kicks
372 * the fan into action.
373 */
374 ds1620_read_state(&th);
375 th_start.lo = 0;
376 th_start.hi = 1;
377 ds1620_write_state(&th_start);
378
379 msleep(2000);
380
381 ds1620_write_state(&th);
382
383 ret = misc_register(&ds1620_miscdev);
384 if (ret < 0)
385 return ret;
386
387#ifdef THERM_USE_PROC
388 proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
389 if (proc_therm_ds1620)
390 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
391 else
392 printk(KERN_ERR "therm: unable to register /proc/therm\n");
393#endif
394
395 ds1620_read_state(&th);
396 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
397
398 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
399 "current %i.%i C, fan %s.\n",
400 th.hi >> 1, th.hi & 1 ? 5 : 0,
401 th.lo >> 1, th.lo & 1 ? 5 : 0,
402 ret >> 1, ret & 1 ? 5 : 0,
403 fan_state[netwinder_get_fan()]);
404
405 return 0;
406}
407
408static void __exit ds1620_exit(void)
409{
410#ifdef THERM_USE_PROC
411 remove_proc_entry("therm", NULL);
412#endif
413 misc_deregister(&ds1620_miscdev);
414}
415
416module_init(ds1620_init);
417module_exit(ds1620_exit);
418
419MODULE_LICENSE("GPL");