xref: /openbmc/linux/drivers/char/ds1620.c (revision 74a22e8f) 
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 stream_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");
424