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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
39static DEFINE_MUTEX(ds1620_mutex);
40static 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 */
49extern unsigned int system_rev;
50
51static inline void netwinder_ds1620_set_clk(int clk)
52{
53 nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54}
55
56static inline void netwinder_ds1620_set_data(int dat)
57{
58 nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59}
60
61static inline int netwinder_ds1620_get_data(void)
62{
63 return nw_gpio_read() & GPIO_DATA;
64}
65
66static inline void netwinder_ds1620_set_data_dir(int dir)
67{
68 nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69}
70
71static 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
77static inline void netwinder_lock(unsigned long *flags)
78{
79 raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
80}
81
82static inline void netwinder_unlock(unsigned long *flags)
83{
84 raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
85}
86
87static 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
96static 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
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 msleep(20);
167}
168
169static 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
192static int cvt_9_to_int(unsigned int val)
193{
194 if (val & 0x100)
195 val |= 0xfffffe00;
196
197 return val;
198}
199
200static 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
208static 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
214static int ds1620_open(struct inode *inode, struct file *file)
215{
216 return stream_open(inode, file);
217}
218
219static ssize_t
220ds1620_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
236static int
237ds1620_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
321static long
322ds1620_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
334static 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
351static 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};
357
358static struct miscdevice ds1620_miscdev = {
359 TEMP_MINOR,
360 "temp",
361 &ds1620_fops
362};
363
364static 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
412static 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
420module_init(ds1620_init);
421module_exit(ds1620_exit);
422
423MODULE_DESCRIPTION("Dallas Semiconductor DS1620 thermometer driver");
424MODULE_LICENSE("GPL");