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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 */
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
39static 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 */
48extern spinlock_t gpio_lock;
49extern unsigned int system_rev;
50
51static inline void netwinder_ds1620_set_clk(int clk)
52{
53 gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54}
55
56static inline void netwinder_ds1620_set_data(int dat)
57{
58 gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59}
60
61static inline int netwinder_ds1620_get_data(void)
62{
63 return gpio_read() & GPIO_DATA;
64}
65
66static inline void netwinder_ds1620_set_data_dir(int dir)
67{
68 gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69}
70
71static 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
77static inline void netwinder_lock(unsigned long *flags)
78{
79 spin_lock_irqsave(&gpio_lock, *flags);
80}
81
82static inline void netwinder_unlock(unsigned long *flags)
83{
84 spin_unlock_irqrestore(&gpio_lock, *flags);
85}
86
87static 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
96static 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
108static 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
123static 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
146static 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
170static 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
193static int cvt_9_to_int(unsigned int val)
194{
195 if (val & 0x100)
196 val |= 0xfffffe00;
197
198 return val;
199}
200
201static 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
209static 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
215static ssize_t
216ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
217{
218 signed int cur_temp;
219 signed char cur_temp_degF;
220
221 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
222
223 /* convert to Fahrenheit, as per wdt.c */
224 cur_temp_degF = (cur_temp * 9) / 5 + 32;
225
226 if (copy_to_user(buf, &cur_temp_degF, 1))
227 return -EFAULT;
228
229 return 1;
230}
231
232static int
233ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
234{
235 struct therm therm;
236 union {
237 struct therm __user *therm;
238 int __user *i;
239 } uarg;
240 int i;
241
242 uarg.i = (int __user *)arg;
243
244 switch(cmd) {
245 case CMD_SET_THERMOSTATE:
246 case CMD_SET_THERMOSTATE2:
247 if (!capable(CAP_SYS_ADMIN))
248 return -EPERM;
249
250 if (cmd == CMD_SET_THERMOSTATE) {
251 if (get_user(therm.hi, uarg.i))
252 return -EFAULT;
253 therm.lo = therm.hi - 3;
254 } else {
255 if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
256 return -EFAULT;
257 }
258
259 therm.lo <<= 1;
260 therm.hi <<= 1;
261
262 ds1620_write_state(&therm);
263 break;
264
265 case CMD_GET_THERMOSTATE:
266 case CMD_GET_THERMOSTATE2:
267 ds1620_read_state(&therm);
268
269 therm.lo >>= 1;
270 therm.hi >>= 1;
271
272 if (cmd == CMD_GET_THERMOSTATE) {
273 if (put_user(therm.hi, uarg.i))
274 return -EFAULT;
275 } else {
276 if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
277 return -EFAULT;
278 }
279 break;
280
281 case CMD_GET_TEMPERATURE:
282 case CMD_GET_TEMPERATURE2:
283 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
284
285 if (cmd == CMD_GET_TEMPERATURE)
286 i >>= 1;
287
288 return put_user(i, uarg.i) ? -EFAULT : 0;
289
290 case CMD_GET_STATUS:
291 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
292
293 return put_user(i, uarg.i) ? -EFAULT : 0;
294
295 case CMD_GET_FAN:
296 i = netwinder_get_fan();
297
298 return put_user(i, uarg.i) ? -EFAULT : 0;
299
300 case CMD_SET_FAN:
301 if (!capable(CAP_SYS_ADMIN))
302 return -EPERM;
303
304 if (get_user(i, uarg.i))
305 return -EFAULT;
306
307 netwinder_set_fan(i);
308 break;
309
310 default:
311 return -ENOIOCTLCMD;
312 }
313
314 return 0;
315}
316
317#ifdef THERM_USE_PROC
318static int
319proc_therm_ds1620_read(char *buf, char **start, off_t offset,
320 int len, int *eof, void *unused)
321{
322 struct therm th;
323 int temp;
324
325 ds1620_read_state(&th);
326 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
327
328 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
329 "temperature: %i.%i C, fan %s\n",
330 th.hi >> 1, th.hi & 1 ? 5 : 0,
331 th.lo >> 1, th.lo & 1 ? 5 : 0,
332 temp >> 1, temp & 1 ? 5 : 0,
333 fan_state[netwinder_get_fan()]);
334
335 return len;
336}
337
338static struct proc_dir_entry *proc_therm_ds1620;
339#endif
340
341static struct file_operations ds1620_fops = {
342 .owner = THIS_MODULE,
343 .open = nonseekable_open,
344 .read = ds1620_read,
345 .ioctl = ds1620_ioctl,
346};
347
348static struct miscdevice ds1620_miscdev = {
349 TEMP_MINOR,
350 "temp",
351 &ds1620_fops
352};
353
354static int __init ds1620_init(void)
355{
356 int ret;
357 struct therm th, th_start;
358
359 if (!machine_is_netwinder())
360 return -ENODEV;
361
362 ds1620_out(THERM_RESET, 0, 0);
363 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
364 ds1620_out(THERM_START_CONVERT, 0, 0);
365
366 /*
367 * Trigger the fan to start by setting
368 * temperature high point low. This kicks
369 * the fan into action.
370 */
371 ds1620_read_state(&th);
372 th_start.lo = 0;
373 th_start.hi = 1;
374 ds1620_write_state(&th_start);
375
376 msleep(2000);
377
378 ds1620_write_state(&th);
379
380 ret = misc_register(&ds1620_miscdev);
381 if (ret < 0)
382 return ret;
383
384#ifdef THERM_USE_PROC
385 proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
386 if (proc_therm_ds1620)
387 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
388 else
389 printk(KERN_ERR "therm: unable to register /proc/therm\n");
390#endif
391
392 ds1620_read_state(&th);
393 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
394
395 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
396 "current %i.%i C, fan %s.\n",
397 th.hi >> 1, th.hi & 1 ? 5 : 0,
398 th.lo >> 1, th.lo & 1 ? 5 : 0,
399 ret >> 1, ret & 1 ? 5 : 0,
400 fan_state[netwinder_get_fan()]);
401
402 return 0;
403}
404
405static void __exit ds1620_exit(void)
406{
407#ifdef THERM_USE_PROC
408 remove_proc_entry("therm", NULL);
409#endif
410 misc_deregister(&ds1620_miscdev);
411}
412
413module_init(ds1620_init);
414module_exit(ds1620_exit);
415
416MODULE_LICENSE("GPL");