tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
12#include <asm/hardware.h>
13#include <asm/mach-types.h>
14#include <asm/uaccess.h>
15#include <asm/therm.h>
16
17#ifdef CONFIG_PROC_FS
18/* define for /proc interface */
19#define THERM_USE_PROC
20#endif
21
22/* Definitions for DS1620 chip */
23#define THERM_START_CONVERT 0xee
24#define THERM_RESET 0xaf
25#define THERM_READ_CONFIG 0xac
26#define THERM_READ_TEMP 0xaa
27#define THERM_READ_TL 0xa2
28#define THERM_READ_TH 0xa1
29#define THERM_WRITE_CONFIG 0x0c
30#define THERM_WRITE_TL 0x02
31#define THERM_WRITE_TH 0x01
32
33#define CFG_CPU 2
34#define CFG_1SHOT 1
35
36static const char *fan_state[] = { "off", "on", "on (hardwired)" };
37
38/*
39 * Start of NetWinder specifics
40 * Note! We have to hold the gpio lock with IRQs disabled over the
41 * whole of our transaction to the Dallas chip, since there is a
42 * chance that the WaveArtist driver could touch these bits to
43 * enable or disable the speaker.
44 */
45extern spinlock_t gpio_lock;
46extern unsigned int system_rev;
47
48static inline void netwinder_ds1620_set_clk(int clk)
49{
50 gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
51}
52
53static inline void netwinder_ds1620_set_data(int dat)
54{
55 gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
56}
57
58static inline int netwinder_ds1620_get_data(void)
59{
60 return gpio_read() & GPIO_DATA;
61}
62
63static inline void netwinder_ds1620_set_data_dir(int dir)
64{
65 gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
66}
67
68static inline void netwinder_ds1620_reset(void)
69{
70 cpld_modify(CPLD_DS_ENABLE, 0);
71 cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
72}
73
74static inline void netwinder_lock(unsigned long *flags)
75{
76 spin_lock_irqsave(&gpio_lock, *flags);
77}
78
79static inline void netwinder_unlock(unsigned long *flags)
80{
81 spin_unlock_irqrestore(&gpio_lock, *flags);
82}
83
84static inline void netwinder_set_fan(int i)
85{
86 unsigned long flags;
87
88 spin_lock_irqsave(&gpio_lock, flags);
89 gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
90 spin_unlock_irqrestore(&gpio_lock, flags);
91}
92
93static inline int netwinder_get_fan(void)
94{
95 if ((system_rev & 0xf000) == 0x4000)
96 return FAN_ALWAYS_ON;
97
98 return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
99}
100
101/*
102 * End of NetWinder specifics
103 */
104
105static 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
120static 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
143static 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
166static 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
189static int cvt_9_to_int(unsigned int val)
190{
191 if (val & 0x100)
192 val |= 0xfffffe00;
193
194 return val;
195}
196
197static 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
205static 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
211static ssize_t
212ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
213{
214 signed int cur_temp;
215 signed char cur_temp_degF;
216
217 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
218
219 /* convert to Fahrenheit, as per wdt.c */
220 cur_temp_degF = (cur_temp * 9) / 5 + 32;
221
222 if (copy_to_user(buf, &cur_temp_degF, 1))
223 return -EFAULT;
224
225 return 1;
226}
227
228static int
229ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
230{
231 struct therm therm;
232 union {
233 struct therm __user *therm;
234 int __user *i;
235 } uarg;
236 int i;
237
238 uarg.i = (int __user *)arg;
239
240 switch(cmd) {
241 case CMD_SET_THERMOSTATE:
242 case CMD_SET_THERMOSTATE2:
243 if (!capable(CAP_SYS_ADMIN))
244 return -EPERM;
245
246 if (cmd == CMD_SET_THERMOSTATE) {
247 if (get_user(therm.hi, uarg.i))
248 return -EFAULT;
249 therm.lo = therm.hi - 3;
250 } else {
251 if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
252 return -EFAULT;
253 }
254
255 therm.lo <<= 1;
256 therm.hi <<= 1;
257
258 ds1620_write_state(&therm);
259 break;
260
261 case CMD_GET_THERMOSTATE:
262 case CMD_GET_THERMOSTATE2:
263 ds1620_read_state(&therm);
264
265 therm.lo >>= 1;
266 therm.hi >>= 1;
267
268 if (cmd == CMD_GET_THERMOSTATE) {
269 if (put_user(therm.hi, uarg.i))
270 return -EFAULT;
271 } else {
272 if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
273 return -EFAULT;
274 }
275 break;
276
277 case CMD_GET_TEMPERATURE:
278 case CMD_GET_TEMPERATURE2:
279 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
280
281 if (cmd == CMD_GET_TEMPERATURE)
282 i >>= 1;
283
284 return put_user(i, uarg.i) ? -EFAULT : 0;
285
286 case CMD_GET_STATUS:
287 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
288
289 return put_user(i, uarg.i) ? -EFAULT : 0;
290
291 case CMD_GET_FAN:
292 i = netwinder_get_fan();
293
294 return put_user(i, uarg.i) ? -EFAULT : 0;
295
296 case CMD_SET_FAN:
297 if (!capable(CAP_SYS_ADMIN))
298 return -EPERM;
299
300 if (get_user(i, uarg.i))
301 return -EFAULT;
302
303 netwinder_set_fan(i);
304 break;
305
306 default:
307 return -ENOIOCTLCMD;
308 }
309
310 return 0;
311}
312
313#ifdef THERM_USE_PROC
314static int
315proc_therm_ds1620_read(char *buf, char **start, off_t offset,
316 int len, int *eof, void *unused)
317{
318 struct therm th;
319 int temp;
320
321 ds1620_read_state(&th);
322 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
323
324 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
325 "temperature: %i.%i C, fan %s\n",
326 th.hi >> 1, th.hi & 1 ? 5 : 0,
327 th.lo >> 1, th.lo & 1 ? 5 : 0,
328 temp >> 1, temp & 1 ? 5 : 0,
329 fan_state[netwinder_get_fan()]);
330
331 return len;
332}
333
334static struct proc_dir_entry *proc_therm_ds1620;
335#endif
336
337static const struct file_operations ds1620_fops = {
338 .owner = THIS_MODULE,
339 .open = nonseekable_open,
340 .read = ds1620_read,
341 .ioctl = ds1620_ioctl,
342};
343
344static struct miscdevice ds1620_miscdev = {
345 TEMP_MINOR,
346 "temp",
347 &ds1620_fops
348};
349
350static int __init ds1620_init(void)
351{
352 int ret;
353 struct therm th, th_start;
354
355 if (!machine_is_netwinder())
356 return -ENODEV;
357
358 ds1620_out(THERM_RESET, 0, 0);
359 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
360 ds1620_out(THERM_START_CONVERT, 0, 0);
361
362 /*
363 * Trigger the fan to start by setting
364 * temperature high point low. This kicks
365 * the fan into action.
366 */
367 ds1620_read_state(&th);
368 th_start.lo = 0;
369 th_start.hi = 1;
370 ds1620_write_state(&th_start);
371
372 msleep(2000);
373
374 ds1620_write_state(&th);
375
376 ret = misc_register(&ds1620_miscdev);
377 if (ret < 0)
378 return ret;
379
380#ifdef THERM_USE_PROC
381 proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
382 if (proc_therm_ds1620)
383 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
384 else
385 printk(KERN_ERR "therm: unable to register /proc/therm\n");
386#endif
387
388 ds1620_read_state(&th);
389 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
390
391 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
392 "current %i.%i C, fan %s.\n",
393 th.hi >> 1, th.hi & 1 ? 5 : 0,
394 th.lo >> 1, th.lo & 1 ? 5 : 0,
395 ret >> 1, ret & 1 ? 5 : 0,
396 fan_state[netwinder_get_fan()]);
397
398 return 0;
399}
400
401static void __exit ds1620_exit(void)
402{
403#ifdef THERM_USE_PROC
404 remove_proc_entry("therm", NULL);
405#endif
406 misc_deregister(&ds1620_miscdev);
407}
408
409module_init(ds1620_init);
410module_exit(ds1620_exit);
411
412MODULE_LICENSE("GPL");