xref: /openbmc/linux/drivers/char/ds1620.c (revision 87c2ce3b) 
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 	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 ssize_t
215 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
216 {
217 	signed int cur_temp;
218 	signed char cur_temp_degF;
219 
220 	cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
221 
222 	/* convert to Fahrenheit, as per wdt.c */
223 	cur_temp_degF = (cur_temp * 9) / 5 + 32;
224 
225 	if (copy_to_user(buf, &cur_temp_degF, 1))
226 		return -EFAULT;
227 
228 	return 1;
229 }
230 
231 static int
232 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
233 {
234 	struct therm therm;
235 	union {
236 		struct therm __user *therm;
237 		int __user *i;
238 	} uarg;
239 	int i;
240 
241 	uarg.i = (int __user *)arg;
242 
243 	switch(cmd) {
244 	case CMD_SET_THERMOSTATE:
245 	case CMD_SET_THERMOSTATE2:
246 		if (!capable(CAP_SYS_ADMIN))
247 			return -EPERM;
248 
249 		if (cmd == CMD_SET_THERMOSTATE) {
250 			if (get_user(therm.hi, uarg.i))
251 				return -EFAULT;
252 			therm.lo = therm.hi - 3;
253 		} else {
254 			if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
255 				return -EFAULT;
256 		}
257 
258 		therm.lo <<= 1;
259 		therm.hi <<= 1;
260 
261 		ds1620_write_state(&therm);
262 		break;
263 
264 	case CMD_GET_THERMOSTATE:
265 	case CMD_GET_THERMOSTATE2:
266 		ds1620_read_state(&therm);
267 
268 		therm.lo >>= 1;
269 		therm.hi >>= 1;
270 
271 		if (cmd == CMD_GET_THERMOSTATE) {
272 			if (put_user(therm.hi, uarg.i))
273 				return -EFAULT;
274 		} else {
275 			if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
276 				return -EFAULT;
277 		}
278 		break;
279 
280 	case CMD_GET_TEMPERATURE:
281 	case CMD_GET_TEMPERATURE2:
282 		i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
283 
284 		if (cmd == CMD_GET_TEMPERATURE)
285 			i >>= 1;
286 
287 		return put_user(i, uarg.i) ? -EFAULT : 0;
288 
289 	case CMD_GET_STATUS:
290 		i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
291 
292 		return put_user(i, uarg.i) ? -EFAULT : 0;
293 
294 	case CMD_GET_FAN:
295 		i = netwinder_get_fan();
296 
297 		return put_user(i, uarg.i) ? -EFAULT : 0;
298 
299 	case CMD_SET_FAN:
300 		if (!capable(CAP_SYS_ADMIN))
301 			return -EPERM;
302 
303 		if (get_user(i, uarg.i))
304 			return -EFAULT;
305 
306 		netwinder_set_fan(i);
307 		break;
308 
309 	default:
310 		return -ENOIOCTLCMD;
311 	}
312 
313 	return 0;
314 }
315 
316 #ifdef THERM_USE_PROC
317 static int
318 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
319 		       int len, int *eof, void *unused)
320 {
321 	struct therm th;
322 	int temp;
323 
324 	ds1620_read_state(&th);
325 	temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
326 
327 	len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
328 		      "temperature: %i.%i C, fan %s\n",
329 		      th.hi >> 1, th.hi & 1 ? 5 : 0,
330 		      th.lo >> 1, th.lo & 1 ? 5 : 0,
331 		      temp  >> 1, temp  & 1 ? 5 : 0,
332 		      fan_state[netwinder_get_fan()]);
333 
334 	return len;
335 }
336 
337 static struct proc_dir_entry *proc_therm_ds1620;
338 #endif
339 
340 static struct file_operations ds1620_fops = {
341 	.owner		= THIS_MODULE,
342 	.open		= nonseekable_open,
343 	.read		= ds1620_read,
344 	.ioctl		= ds1620_ioctl,
345 };
346 
347 static struct miscdevice ds1620_miscdev = {
348 	TEMP_MINOR,
349 	"temp",
350 	&ds1620_fops
351 };
352 
353 static int __init ds1620_init(void)
354 {
355 	int ret;
356 	struct therm th, th_start;
357 
358 	if (!machine_is_netwinder())
359 		return -ENODEV;
360 
361 	ds1620_out(THERM_RESET, 0, 0);
362 	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
363 	ds1620_out(THERM_START_CONVERT, 0, 0);
364 
365 	/*
366 	 * Trigger the fan to start by setting
367 	 * temperature high point low.  This kicks
368 	 * the fan into action.
369 	 */
370 	ds1620_read_state(&th);
371 	th_start.lo = 0;
372 	th_start.hi = 1;
373 	ds1620_write_state(&th_start);
374 
375 	msleep(2000);
376 
377 	ds1620_write_state(&th);
378 
379 	ret = misc_register(&ds1620_miscdev);
380 	if (ret < 0)
381 		return ret;
382 
383 #ifdef THERM_USE_PROC
384 	proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
385 	if (proc_therm_ds1620)
386 		proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
387 	else
388 		printk(KERN_ERR "therm: unable to register /proc/therm\n");
389 #endif
390 
391 	ds1620_read_state(&th);
392 	ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
393 
394 	printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
395 	       "current %i.%i C, fan %s.\n",
396 	       th.hi >> 1, th.hi & 1 ? 5 : 0,
397 	       th.lo >> 1, th.lo & 1 ? 5 : 0,
398 	       ret   >> 1, ret   & 1 ? 5 : 0,
399 	       fan_state[netwinder_get_fan()]);
400 
401 	return 0;
402 }
403 
404 static void __exit ds1620_exit(void)
405 {
406 #ifdef THERM_USE_PROC
407 	remove_proc_entry("therm", NULL);
408 #endif
409 	misc_deregister(&ds1620_miscdev);
410 }
411 
412 module_init(ds1620_init);
413 module_exit(ds1620_exit);
414 
415 MODULE_LICENSE("GPL");
416