Merge branch 'for-5.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj...
[linux-2.6-microblaze.git] / drivers / char / ds1620.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
4  *   thermometer driver (as used in the Rebel.com NetWinder)
5  */
6 #include <linux/module.h>
7 #include <linux/miscdevice.h>
8 #include <linux/delay.h>
9 #include <linux/proc_fs.h>
10 #include <linux/seq_file.h>
11 #include <linux/capability.h>
12 #include <linux/init.h>
13 #include <linux/mutex.h>
14
15 #include <mach/hardware.h>
16 #include <asm/mach-types.h>
17 #include <linux/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
39 static DEFINE_MUTEX(ds1620_mutex);
40 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
41
42 /*
43  * Start of NetWinder specifics
44  *  Note!  We have to hold the gpio lock with IRQs disabled over the
45  *  whole of our transaction to the Dallas chip, since there is a
46  *  chance that the WaveArtist driver could touch these bits to
47  *  enable or disable the speaker.
48  */
49 extern unsigned int system_rev;
50
51 static inline void netwinder_ds1620_set_clk(int clk)
52 {
53         nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54 }
55
56 static inline void netwinder_ds1620_set_data(int dat)
57 {
58         nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59 }
60
61 static inline int netwinder_ds1620_get_data(void)
62 {
63         return nw_gpio_read() & GPIO_DATA;
64 }
65
66 static inline void netwinder_ds1620_set_data_dir(int dir)
67 {
68         nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69 }
70
71 static inline void netwinder_ds1620_reset(void)
72 {
73         nw_cpld_modify(CPLD_DS_ENABLE, 0);
74         nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
75 }
76
77 static inline void netwinder_lock(unsigned long *flags)
78 {
79         raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
80 }
81
82 static inline void netwinder_unlock(unsigned long *flags)
83 {
84         raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
85 }
86
87 static inline void netwinder_set_fan(int i)
88 {
89         unsigned long flags;
90
91         raw_spin_lock_irqsave(&nw_gpio_lock, flags);
92         nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
93         raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
94 }
95
96 static inline int netwinder_get_fan(void)
97 {
98         if ((system_rev & 0xf000) == 0x4000)
99                 return FAN_ALWAYS_ON;
100
101         return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
102 }
103
104 /*
105  * End of NetWinder specifics
106  */
107
108 static 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
123 static 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
146 static 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         msleep(20);
167 }
168
169 static unsigned int ds1620_in(int cmd, int bits)
170 {
171         unsigned long flags;
172         unsigned int value;
173
174         netwinder_lock(&flags);
175         netwinder_ds1620_set_clk(1);
176         netwinder_ds1620_set_data_dir(0);
177         netwinder_ds1620_reset();
178
179         udelay(1);
180
181         ds1620_send_bits(8, cmd);
182
183         netwinder_ds1620_set_data_dir(1);
184         value = ds1620_recv_bits(bits);
185
186         netwinder_ds1620_reset();
187         netwinder_unlock(&flags);
188
189         return value;
190 }
191
192 static int cvt_9_to_int(unsigned int val)
193 {
194         if (val & 0x100)
195                 val |= 0xfffffe00;
196
197         return val;
198 }
199
200 static void ds1620_write_state(struct therm *therm)
201 {
202         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
203         ds1620_out(THERM_WRITE_TL, 9, therm->lo);
204         ds1620_out(THERM_WRITE_TH, 9, therm->hi);
205         ds1620_out(THERM_START_CONVERT, 0, 0);
206 }
207
208 static void ds1620_read_state(struct therm *therm)
209 {
210         therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
211         therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
212 }
213
214 static int ds1620_open(struct inode *inode, struct file *file)
215 {
216         return stream_open(inode, file);
217 }
218
219 static ssize_t
220 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
221 {
222         signed int cur_temp;
223         signed char cur_temp_degF;
224
225         cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
226
227         /* convert to Fahrenheit, as per wdt.c */
228         cur_temp_degF = (cur_temp * 9) / 5 + 32;
229
230         if (copy_to_user(buf, &cur_temp_degF, 1))
231                 return -EFAULT;
232
233         return 1;
234 }
235
236 static int
237 ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
238 {
239         struct therm therm;
240         union {
241                 struct therm __user *therm;
242                 int __user *i;
243         } uarg;
244         int i;
245
246         uarg.i = (int __user *)arg;
247
248         switch(cmd) {
249         case CMD_SET_THERMOSTATE:
250         case CMD_SET_THERMOSTATE2:
251                 if (!capable(CAP_SYS_ADMIN))
252                         return -EPERM;
253
254                 if (cmd == CMD_SET_THERMOSTATE) {
255                         if (get_user(therm.hi, uarg.i))
256                                 return -EFAULT;
257                         therm.lo = therm.hi - 3;
258                 } else {
259                         if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
260                                 return -EFAULT;
261                 }
262
263                 therm.lo <<= 1;
264                 therm.hi <<= 1;
265
266                 ds1620_write_state(&therm);
267                 break;
268
269         case CMD_GET_THERMOSTATE:
270         case CMD_GET_THERMOSTATE2:
271                 ds1620_read_state(&therm);
272
273                 therm.lo >>= 1;
274                 therm.hi >>= 1;
275
276                 if (cmd == CMD_GET_THERMOSTATE) {
277                         if (put_user(therm.hi, uarg.i))
278                                 return -EFAULT;
279                 } else {
280                         if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
281                                 return -EFAULT;
282                 }
283                 break;
284
285         case CMD_GET_TEMPERATURE:
286         case CMD_GET_TEMPERATURE2:
287                 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
288
289                 if (cmd == CMD_GET_TEMPERATURE)
290                         i >>= 1;
291
292                 return put_user(i, uarg.i) ? -EFAULT : 0;
293
294         case CMD_GET_STATUS:
295                 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
296
297                 return put_user(i, uarg.i) ? -EFAULT : 0;
298
299         case CMD_GET_FAN:
300                 i = netwinder_get_fan();
301
302                 return put_user(i, uarg.i) ? -EFAULT : 0;
303
304         case CMD_SET_FAN:
305                 if (!capable(CAP_SYS_ADMIN))
306                         return -EPERM;
307
308                 if (get_user(i, uarg.i))
309                         return -EFAULT;
310
311                 netwinder_set_fan(i);
312                 break;
313                 
314         default:
315                 return -ENOIOCTLCMD;
316         }
317
318         return 0;
319 }
320
321 static long
322 ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
323 {
324         int ret;
325
326         mutex_lock(&ds1620_mutex);
327         ret = ds1620_ioctl(file, cmd, arg);
328         mutex_unlock(&ds1620_mutex);
329
330         return ret;
331 }
332
333 #ifdef THERM_USE_PROC
334 static int ds1620_proc_therm_show(struct seq_file *m, void *v)
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         seq_printf(m, "Thermostat: HI %i.%i, LOW %i.%i; temperature: %i.%i C, fan %s\n",
343                    th.hi >> 1, th.hi & 1 ? 5 : 0,
344                    th.lo >> 1, th.lo & 1 ? 5 : 0,
345                    temp  >> 1, temp  & 1 ? 5 : 0,
346                    fan_state[netwinder_get_fan()]);
347         return 0;
348 }
349 #endif
350
351 static const struct file_operations ds1620_fops = {
352         .owner          = THIS_MODULE,
353         .open           = ds1620_open,
354         .read           = ds1620_read,
355         .unlocked_ioctl = ds1620_unlocked_ioctl,
356         .llseek         = no_llseek,
357 };
358
359 static struct miscdevice ds1620_miscdev = {
360         TEMP_MINOR,
361         "temp",
362         &ds1620_fops
363 };
364
365 static int __init ds1620_init(void)
366 {
367         int ret;
368         struct therm th, th_start;
369
370         if (!machine_is_netwinder())
371                 return -ENODEV;
372
373         ds1620_out(THERM_RESET, 0, 0);
374         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
375         ds1620_out(THERM_START_CONVERT, 0, 0);
376
377         /*
378          * Trigger the fan to start by setting
379          * temperature high point low.  This kicks
380          * the fan into action.
381          */
382         ds1620_read_state(&th);
383         th_start.lo = 0;
384         th_start.hi = 1;
385         ds1620_write_state(&th_start);
386
387         msleep(2000);
388
389         ds1620_write_state(&th);
390
391         ret = misc_register(&ds1620_miscdev);
392         if (ret < 0)
393                 return ret;
394
395 #ifdef THERM_USE_PROC
396         if (!proc_create_single("therm", 0, NULL, ds1620_proc_therm_show))
397                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
398 #endif
399
400         ds1620_read_state(&th);
401         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
402
403         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
404                "current %i.%i C, fan %s.\n",
405                th.hi >> 1, th.hi & 1 ? 5 : 0,
406                th.lo >> 1, th.lo & 1 ? 5 : 0,
407                ret   >> 1, ret   & 1 ? 5 : 0,
408                fan_state[netwinder_get_fan()]);
409
410         return 0;
411 }
412
413 static void __exit ds1620_exit(void)
414 {
415 #ifdef THERM_USE_PROC
416         remove_proc_entry("therm", NULL);
417 #endif
418         misc_deregister(&ds1620_miscdev);
419 }
420
421 module_init(ds1620_init);
422 module_exit(ds1620_exit);
423
424 MODULE_LICENSE("GPL");