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	.llseek		= no_llseek,
357};
358
359static struct miscdevice ds1620_miscdev = {
360	TEMP_MINOR,
361	"temp",
362	&ds1620_fops
363};
364
365static 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
413static 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
421module_init(ds1620_init);
422module_exit(ds1620_exit);
423
424MODULE_LICENSE("GPL");

 
  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/capability.h>
 10#include <linux/init.h>
 11#include <linux/mutex.h>
 12
 13#include <mach/hardware.h>
 14#include <asm/mach-types.h>
 15#include <asm/uaccess.h>
 16#include <asm/therm.h>
 17
 18#ifdef CONFIG_PROC_FS
 19/* define for /proc interface */
 20#define THERM_USE_PROC
 21#endif
 22
 23/* Definitions for DS1620 chip */
 24#define THERM_START_CONVERT	0xee
 25#define THERM_RESET		0xaf
 26#define THERM_READ_CONFIG	0xac
 27#define THERM_READ_TEMP		0xaa
 28#define THERM_READ_TL		0xa2
 29#define THERM_READ_TH		0xa1
 30#define THERM_WRITE_CONFIG	0x0c
 31#define THERM_WRITE_TL		0x02
 32#define THERM_WRITE_TH		0x01
 33
 34#define CFG_CPU			2
 35#define CFG_1SHOT		1
 36
 37static DEFINE_MUTEX(ds1620_mutex);
 38static const char *fan_state[] = { "off", "on", "on (hardwired)" };
 39
 40/*
 41 * Start of NetWinder specifics
 42 *  Note!  We have to hold the gpio lock with IRQs disabled over the
 43 *  whole of our transaction to the Dallas chip, since there is a
 44 *  chance that the WaveArtist driver could touch these bits to
 45 *  enable or disable the speaker.
 46 */
 47extern unsigned int system_rev;
 48
 49static inline void netwinder_ds1620_set_clk(int clk)
 50{
 51	nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
 52}
 53
 54static inline void netwinder_ds1620_set_data(int dat)
 55{
 56	nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
 57}
 58
 59static inline int netwinder_ds1620_get_data(void)
 60{
 61	return nw_gpio_read() & GPIO_DATA;
 62}
 63
 64static inline void netwinder_ds1620_set_data_dir(int dir)
 65{
 66	nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
 67}
 68
 69static inline void netwinder_ds1620_reset(void)
 70{
 71	nw_cpld_modify(CPLD_DS_ENABLE, 0);
 72	nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
 73}
 74
 75static inline void netwinder_lock(unsigned long *flags)
 76{
 77	spin_lock_irqsave(&nw_gpio_lock, *flags);
 78}
 79
 80static inline void netwinder_unlock(unsigned long *flags)
 81{
 82	spin_unlock_irqrestore(&nw_gpio_lock, *flags);
 83}
 84
 85static inline void netwinder_set_fan(int i)
 86{
 87	unsigned long flags;
 88
 89	spin_lock_irqsave(&nw_gpio_lock, flags);
 90	nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
 91	spin_unlock_irqrestore(&nw_gpio_lock, flags);
 92}
 93
 94static inline int netwinder_get_fan(void)
 95{
 96	if ((system_rev & 0xf000) == 0x4000)
 97		return FAN_ALWAYS_ON;
 98
 99	return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
100}
101
102/*
103 * End of NetWinder specifics
104 */
105
106static void ds1620_send_bits(int nr, int value)
107{
108	int i;
109
110	for (i = 0; i < nr; i++) {
111		netwinder_ds1620_set_data(value & 1);
112		netwinder_ds1620_set_clk(0);
113		udelay(1);
114		netwinder_ds1620_set_clk(1);
115		udelay(1);
116
117		value >>= 1;
118	}
119}
120
121static unsigned int ds1620_recv_bits(int nr)
122{
123	unsigned int value = 0, mask = 1;
124	int i;
125
126	netwinder_ds1620_set_data(0);
127
128	for (i = 0; i < nr; i++) {
129		netwinder_ds1620_set_clk(0);
130		udelay(1);
131
132		if (netwinder_ds1620_get_data())
133			value |= mask;
134
135		mask <<= 1;
136
137		netwinder_ds1620_set_clk(1);
138		udelay(1);
139	}
140
141	return value;
142}
143
144static void ds1620_out(int cmd, int bits, int value)
145{
146	unsigned long flags;
147
148	netwinder_lock(&flags);
149	netwinder_ds1620_set_clk(1);
150	netwinder_ds1620_set_data_dir(0);
151	netwinder_ds1620_reset();
152
153	udelay(1);
154
155	ds1620_send_bits(8, cmd);
156	if (bits)
157		ds1620_send_bits(bits, value);
158
159	udelay(1);
160
161	netwinder_ds1620_reset();
162	netwinder_unlock(&flags);
163
164	msleep(20);
165}
166
167static unsigned int ds1620_in(int cmd, int bits)
168{
169	unsigned long flags;
170	unsigned int value;
171
172	netwinder_lock(&flags);
173	netwinder_ds1620_set_clk(1);
174	netwinder_ds1620_set_data_dir(0);
175	netwinder_ds1620_reset();
176
177	udelay(1);
178
179	ds1620_send_bits(8, cmd);
180
181	netwinder_ds1620_set_data_dir(1);
182	value = ds1620_recv_bits(bits);
183
184	netwinder_ds1620_reset();
185	netwinder_unlock(&flags);
186
187	return value;
188}
189
190static int cvt_9_to_int(unsigned int val)
191{
192	if (val & 0x100)
193		val |= 0xfffffe00;
194
195	return val;
196}
197
198static void ds1620_write_state(struct therm *therm)
199{
200	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
201	ds1620_out(THERM_WRITE_TL, 9, therm->lo);
202	ds1620_out(THERM_WRITE_TH, 9, therm->hi);
203	ds1620_out(THERM_START_CONVERT, 0, 0);
204}
205
206static void ds1620_read_state(struct therm *therm)
207{
208	therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
209	therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
210}
211
212static int ds1620_open(struct inode *inode, struct file *file)
213{
214	return nonseekable_open(inode, file);
215}
216
217static ssize_t
218ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
219{
220	signed int cur_temp;
221	signed char cur_temp_degF;
222
223	cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
224
225	/* convert to Fahrenheit, as per wdt.c */
226	cur_temp_degF = (cur_temp * 9) / 5 + 32;
227
228	if (copy_to_user(buf, &cur_temp_degF, 1))
229		return -EFAULT;
230
231	return 1;
232}
233
234static int
235ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
236{
237	struct therm therm;
238	union {
239		struct therm __user *therm;
240		int __user *i;
241	} uarg;
242	int i;
243
244	uarg.i = (int __user *)arg;
245
246	switch(cmd) {
247	case CMD_SET_THERMOSTATE:
248	case CMD_SET_THERMOSTATE2:
249		if (!capable(CAP_SYS_ADMIN))
250			return -EPERM;
251
252		if (cmd == CMD_SET_THERMOSTATE) {
253			if (get_user(therm.hi, uarg.i))
254				return -EFAULT;
255			therm.lo = therm.hi - 3;
256		} else {
257			if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
258				return -EFAULT;
259		}
260
261		therm.lo <<= 1;
262		therm.hi <<= 1;
263
264		ds1620_write_state(&therm);
265		break;
266
267	case CMD_GET_THERMOSTATE:
268	case CMD_GET_THERMOSTATE2:
269		ds1620_read_state(&therm);
270
271		therm.lo >>= 1;
272		therm.hi >>= 1;
273
274		if (cmd == CMD_GET_THERMOSTATE) {
275			if (put_user(therm.hi, uarg.i))
276				return -EFAULT;
277		} else {
278			if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
279				return -EFAULT;
280		}
281		break;
282
283	case CMD_GET_TEMPERATURE:
284	case CMD_GET_TEMPERATURE2:
285		i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
286
287		if (cmd == CMD_GET_TEMPERATURE)
288			i >>= 1;
289
290		return put_user(i, uarg.i) ? -EFAULT : 0;
291
292	case CMD_GET_STATUS:
293		i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
294
295		return put_user(i, uarg.i) ? -EFAULT : 0;
296
297	case CMD_GET_FAN:
298		i = netwinder_get_fan();
299
300		return put_user(i, uarg.i) ? -EFAULT : 0;
301
302	case CMD_SET_FAN:
303		if (!capable(CAP_SYS_ADMIN))
304			return -EPERM;
305
306		if (get_user(i, uarg.i))
307			return -EFAULT;
308
309		netwinder_set_fan(i);
310		break;
311		
312	default:
313		return -ENOIOCTLCMD;
314	}
315
316	return 0;
317}
318
319static long
320ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
321{
322	int ret;
323
324	mutex_lock(&ds1620_mutex);
325	ret = ds1620_ioctl(file, cmd, arg);
326	mutex_unlock(&ds1620_mutex);
327
328	return ret;
329}
330
331#ifdef THERM_USE_PROC
332static int
333proc_therm_ds1620_read(char *buf, char **start, off_t offset,
334		       int len, int *eof, void *unused)
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	len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
343		      "temperature: %i.%i C, fan %s\n",
344		      th.hi >> 1, th.hi & 1 ? 5 : 0,
345		      th.lo >> 1, th.lo & 1 ? 5 : 0,
346		      temp  >> 1, temp  & 1 ? 5 : 0,
347		      fan_state[netwinder_get_fan()]);
348
349	return len;
350}
351
352static struct proc_dir_entry *proc_therm_ds1620;
353#endif
354
355static const struct file_operations ds1620_fops = {
356	.owner		= THIS_MODULE,
357	.open		= ds1620_open,
358	.read		= ds1620_read,
359	.unlocked_ioctl	= ds1620_unlocked_ioctl,
360	.llseek		= no_llseek,
361};
362
363static struct miscdevice ds1620_miscdev = {
364	TEMP_MINOR,
365	"temp",
366	&ds1620_fops
367};
368
369static int __init ds1620_init(void)
370{
371	int ret;
372	struct therm th, th_start;
373
374	if (!machine_is_netwinder())
375		return -ENODEV;
376
377	ds1620_out(THERM_RESET, 0, 0);
378	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
379	ds1620_out(THERM_START_CONVERT, 0, 0);
380
381	/*
382	 * Trigger the fan to start by setting
383	 * temperature high point low.  This kicks
384	 * the fan into action.
385	 */
386	ds1620_read_state(&th);
387	th_start.lo = 0;
388	th_start.hi = 1;
389	ds1620_write_state(&th_start);
390
391	msleep(2000);
392
393	ds1620_write_state(&th);
394
395	ret = misc_register(&ds1620_miscdev);
396	if (ret < 0)
397		return ret;
398
399#ifdef THERM_USE_PROC
400	proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
401	if (proc_therm_ds1620)
402		proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
403	else
404		printk(KERN_ERR "therm: unable to register /proc/therm\n");
405#endif
406
407	ds1620_read_state(&th);
408	ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
409
410	printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
411	       "current %i.%i C, fan %s.\n",
412	       th.hi >> 1, th.hi & 1 ? 5 : 0,
413	       th.lo >> 1, th.lo & 1 ? 5 : 0,
414	       ret   >> 1, ret   & 1 ? 5 : 0,
415	       fan_state[netwinder_get_fan()]);
416
417	return 0;
418}
419
420static void __exit ds1620_exit(void)
421{
422#ifdef THERM_USE_PROC
423	remove_proc_entry("therm", NULL);
424#endif
425	misc_deregister(&ds1620_miscdev);
426}
427
428module_init(ds1620_init);
429module_exit(ds1620_exit);
430
431MODULE_LICENSE("GPL");