a5ecf6dae02ebd93df78af0b8d17f08a824c90f7
[sfrench/cifs-2.6.git] / 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/module.h>
6 #include <linux/miscdevice.h>
7 #include <linux/delay.h>
8 #include <linux/proc_fs.h>
9 #include <linux/seq_file.h>
10 #include <linux/capability.h>
11 #include <linux/init.h>
12 #include <linux/mutex.h>
13
14 #include <mach/hardware.h>
15 #include <asm/mach-types.h>
16 #include <linux/uaccess.h>
17 #include <asm/therm.h>
18
19 #ifdef CONFIG_PROC_FS
20 /* define for /proc interface */
21 #define THERM_USE_PROC
22 #endif
23
24 /* Definitions for DS1620 chip */
25 #define THERM_START_CONVERT     0xee
26 #define THERM_RESET             0xaf
27 #define THERM_READ_CONFIG       0xac
28 #define THERM_READ_TEMP         0xaa
29 #define THERM_READ_TL           0xa2
30 #define THERM_READ_TH           0xa1
31 #define THERM_WRITE_CONFIG      0x0c
32 #define THERM_WRITE_TL          0x02
33 #define THERM_WRITE_TH          0x01
34
35 #define CFG_CPU                 2
36 #define CFG_1SHOT               1
37
38 static DEFINE_MUTEX(ds1620_mutex);
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 unsigned int system_rev;
49
50 static inline void netwinder_ds1620_set_clk(int clk)
51 {
52         nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
53 }
54
55 static inline void netwinder_ds1620_set_data(int dat)
56 {
57         nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
58 }
59
60 static inline int netwinder_ds1620_get_data(void)
61 {
62         return nw_gpio_read() & GPIO_DATA;
63 }
64
65 static inline void netwinder_ds1620_set_data_dir(int dir)
66 {
67         nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
68 }
69
70 static inline void netwinder_ds1620_reset(void)
71 {
72         nw_cpld_modify(CPLD_DS_ENABLE, 0);
73         nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
74 }
75
76 static inline void netwinder_lock(unsigned long *flags)
77 {
78         raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
79 }
80
81 static inline void netwinder_unlock(unsigned long *flags)
82 {
83         raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
84 }
85
86 static inline void netwinder_set_fan(int i)
87 {
88         unsigned long flags;
89
90         raw_spin_lock_irqsave(&nw_gpio_lock, flags);
91         nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
92         raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
93 }
94
95 static inline int netwinder_get_fan(void)
96 {
97         if ((system_rev & 0xf000) == 0x4000)
98                 return FAN_ALWAYS_ON;
99
100         return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
101 }
102
103 /*
104  * End of NetWinder specifics
105  */
106
107 static void ds1620_send_bits(int nr, int value)
108 {
109         int i;
110
111         for (i = 0; i < nr; i++) {
112                 netwinder_ds1620_set_data(value & 1);
113                 netwinder_ds1620_set_clk(0);
114                 udelay(1);
115                 netwinder_ds1620_set_clk(1);
116                 udelay(1);
117
118                 value >>= 1;
119         }
120 }
121
122 static unsigned int ds1620_recv_bits(int nr)
123 {
124         unsigned int value = 0, mask = 1;
125         int i;
126
127         netwinder_ds1620_set_data(0);
128
129         for (i = 0; i < nr; i++) {
130                 netwinder_ds1620_set_clk(0);
131                 udelay(1);
132
133                 if (netwinder_ds1620_get_data())
134                         value |= mask;
135
136                 mask <<= 1;
137
138                 netwinder_ds1620_set_clk(1);
139                 udelay(1);
140         }
141
142         return value;
143 }
144
145 static void ds1620_out(int cmd, int bits, int value)
146 {
147         unsigned long flags;
148
149         netwinder_lock(&flags);
150         netwinder_ds1620_set_clk(1);
151         netwinder_ds1620_set_data_dir(0);
152         netwinder_ds1620_reset();
153
154         udelay(1);
155
156         ds1620_send_bits(8, cmd);
157         if (bits)
158                 ds1620_send_bits(bits, value);
159
160         udelay(1);
161
162         netwinder_ds1620_reset();
163         netwinder_unlock(&flags);
164
165         msleep(20);
166 }
167
168 static unsigned int ds1620_in(int cmd, int bits)
169 {
170         unsigned long flags;
171         unsigned int value;
172
173         netwinder_lock(&flags);
174         netwinder_ds1620_set_clk(1);
175         netwinder_ds1620_set_data_dir(0);
176         netwinder_ds1620_reset();
177
178         udelay(1);
179
180         ds1620_send_bits(8, cmd);
181
182         netwinder_ds1620_set_data_dir(1);
183         value = ds1620_recv_bits(bits);
184
185         netwinder_ds1620_reset();
186         netwinder_unlock(&flags);
187
188         return value;
189 }
190
191 static int cvt_9_to_int(unsigned int val)
192 {
193         if (val & 0x100)
194                 val |= 0xfffffe00;
195
196         return val;
197 }
198
199 static void ds1620_write_state(struct therm *therm)
200 {
201         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
202         ds1620_out(THERM_WRITE_TL, 9, therm->lo);
203         ds1620_out(THERM_WRITE_TH, 9, therm->hi);
204         ds1620_out(THERM_START_CONVERT, 0, 0);
205 }
206
207 static void ds1620_read_state(struct therm *therm)
208 {
209         therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
210         therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
211 }
212
213 static int ds1620_open(struct inode *inode, struct file *file)
214 {
215         return nonseekable_open(inode, file);
216 }
217
218 static ssize_t
219 ds1620_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
235 static int
236 ds1620_ioctl(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 static long
321 ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
322 {
323         int ret;
324
325         mutex_lock(&ds1620_mutex);
326         ret = ds1620_ioctl(file, cmd, arg);
327         mutex_unlock(&ds1620_mutex);
328
329         return ret;
330 }
331
332 #ifdef THERM_USE_PROC
333 static int ds1620_proc_therm_show(struct seq_file *m, void *v)
334 {
335         struct therm th;
336         int temp;
337
338         ds1620_read_state(&th);
339         temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
340
341         seq_printf(m, "Thermostat: HI %i.%i, LOW %i.%i; temperature: %i.%i C, fan %s\n",
342                    th.hi >> 1, th.hi & 1 ? 5 : 0,
343                    th.lo >> 1, th.lo & 1 ? 5 : 0,
344                    temp  >> 1, temp  & 1 ? 5 : 0,
345                    fan_state[netwinder_get_fan()]);
346         return 0;
347 }
348 #endif
349
350 static const struct file_operations ds1620_fops = {
351         .owner          = THIS_MODULE,
352         .open           = ds1620_open,
353         .read           = ds1620_read,
354         .unlocked_ioctl = ds1620_unlocked_ioctl,
355         .llseek         = no_llseek,
356 };
357
358 static struct miscdevice ds1620_miscdev = {
359         TEMP_MINOR,
360         "temp",
361         &ds1620_fops
362 };
363
364 static int __init ds1620_init(void)
365 {
366         int ret;
367         struct therm th, th_start;
368
369         if (!machine_is_netwinder())
370                 return -ENODEV;
371
372         ds1620_out(THERM_RESET, 0, 0);
373         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
374         ds1620_out(THERM_START_CONVERT, 0, 0);
375
376         /*
377          * Trigger the fan to start by setting
378          * temperature high point low.  This kicks
379          * the fan into action.
380          */
381         ds1620_read_state(&th);
382         th_start.lo = 0;
383         th_start.hi = 1;
384         ds1620_write_state(&th_start);
385
386         msleep(2000);
387
388         ds1620_write_state(&th);
389
390         ret = misc_register(&ds1620_miscdev);
391         if (ret < 0)
392                 return ret;
393
394 #ifdef THERM_USE_PROC
395         if (!proc_create_single("therm", 0, NULL, ds1620_proc_therm_show))
396                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
397 #endif
398
399         ds1620_read_state(&th);
400         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
401
402         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
403                "current %i.%i C, fan %s.\n",
404                th.hi >> 1, th.hi & 1 ? 5 : 0,
405                th.lo >> 1, th.lo & 1 ? 5 : 0,
406                ret   >> 1, ret   & 1 ? 5 : 0,
407                fan_state[netwinder_get_fan()]);
408
409         return 0;
410 }
411
412 static void __exit ds1620_exit(void)
413 {
414 #ifdef THERM_USE_PROC
415         remove_proc_entry("therm", NULL);
416 #endif
417         misc_deregister(&ds1620_miscdev);
418 }
419
420 module_init(ds1620_init);
421 module_exit(ds1620_exit);
422
423 MODULE_LICENSE("GPL");