xref: /openbmc/linux/drivers/char/ds1620.c (revision 4bedea94) 
1 /*
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 
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 spinlock_t gpio_lock;
49 extern unsigned int system_rev;
50 
51 static inline void netwinder_ds1620_set_clk(int clk)
52 {
53 	gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54 }
55 
56 static inline void netwinder_ds1620_set_data(int dat)
57 {
58 	gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59 }
60 
61 static inline int netwinder_ds1620_get_data(void)
62 {
63 	return gpio_read() & GPIO_DATA;
64 }
65 
66 static inline void netwinder_ds1620_set_data_dir(int dir)
67 {
68 	gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69 }
70 
71 static 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 
77 static inline void netwinder_lock(unsigned long *flags)
78 {
79 	spin_lock_irqsave(&gpio_lock, *flags);
80 }
81 
82 static inline void netwinder_unlock(unsigned long *flags)
83 {
84 	spin_unlock_irqrestore(&gpio_lock, *flags);
85 }
86 
87 static 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 
96 static 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 
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 	set_current_state(TASK_INTERRUPTIBLE);
167 	schedule_timeout(2);
168 }
169 
170 static 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 
193 static int cvt_9_to_int(unsigned int val)
194 {
195 	if (val & 0x100)
196 		val |= 0xfffffe00;
197 
198 	return val;
199 }
200 
201 static 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 
209 static 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 
215 static ssize_t
216 ds1620_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 
232 static int
233 ds1620_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
318 static int
319 proc_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 
338 static struct proc_dir_entry *proc_therm_ds1620;
339 #endif
340 
341 static struct file_operations ds1620_fops = {
342 	.owner		= THIS_MODULE,
343 	.open		= nonseekable_open,
344 	.read		= ds1620_read,
345 	.ioctl		= ds1620_ioctl,
346 };
347 
348 static struct miscdevice ds1620_miscdev = {
349 	TEMP_MINOR,
350 	"temp",
351 	&ds1620_fops
352 };
353 
354 static 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 
405 static 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 
413 module_init(ds1620_init);
414 module_exit(ds1620_exit);
415 
416 MODULE_LICENSE("GPL");
417