[net-next-2.6.git] / drivers / char / ds1620.c

/*
 * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
 *   thermometer driver (as used in the Rebel.com NetWinder)
 */
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/smp_lock.h>

#include <mach/hardware.h>
#include <asm/mach-types.h>
#include <asm/uaccess.h>
#include <asm/therm.h>

#ifdef CONFIG_PROC_FS
/* define for /proc interface */
#define THERM_USE_PROC
#endif

/* Definitions for DS1620 chip */
#define THERM_START_CONVERT	0xee
#define THERM_RESET		0xaf
#define THERM_READ_CONFIG	0xac
#define THERM_READ_TEMP		0xaa
#define THERM_READ_TL		0xa2
#define THERM_READ_TH		0xa1
#define THERM_WRITE_CONFIG	0x0c
#define THERM_WRITE_TL		0x02
#define THERM_WRITE_TH		0x01

#define CFG_CPU			2
#define CFG_1SHOT		1

static const char *fan_state[] = { "off", "on", "on (hardwired)" };

/*
 * Start of NetWinder specifics
 *  Note!  We have to hold the gpio lock with IRQs disabled over the
 *  whole of our transaction to the Dallas chip, since there is a
 *  chance that the WaveArtist driver could touch these bits to
 *  enable or disable the speaker.
 */
extern unsigned int system_rev;

static inline void netwinder_ds1620_set_clk(int clk)
{
	nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
}

static inline void netwinder_ds1620_set_data(int dat)
{
	nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
}

static inline int netwinder_ds1620_get_data(void)
{
	return nw_gpio_read() & GPIO_DATA;
}

static inline void netwinder_ds1620_set_data_dir(int dir)
{
	nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
}

static inline void netwinder_ds1620_reset(void)
{
	nw_cpld_modify(CPLD_DS_ENABLE, 0);
	nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
}

static inline void netwinder_lock(unsigned long *flags)
{
	spin_lock_irqsave(&nw_gpio_lock, *flags);
}

static inline void netwinder_unlock(unsigned long *flags)
{
	spin_unlock_irqrestore(&nw_gpio_lock, *flags);
}

static inline void netwinder_set_fan(int i)
{
	unsigned long flags;

	spin_lock_irqsave(&nw_gpio_lock, flags);
	nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
	spin_unlock_irqrestore(&nw_gpio_lock, flags);
}

static inline int netwinder_get_fan(void)
{
	if ((system_rev & 0xf000) == 0x4000)
		return FAN_ALWAYS_ON;

	return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
}

/*
 * End of NetWinder specifics
 */

static void ds1620_send_bits(int nr, int value)
{
	int i;

	for (i = 0; i < nr; i++) {
		netwinder_ds1620_set_data(value & 1);
		netwinder_ds1620_set_clk(0);
		udelay(1);
		netwinder_ds1620_set_clk(1);
		udelay(1);

		value >>= 1;
	}
}

static unsigned int ds1620_recv_bits(int nr)
{
	unsigned int value = 0, mask = 1;
	int i;

	netwinder_ds1620_set_data(0);

	for (i = 0; i < nr; i++) {
		netwinder_ds1620_set_clk(0);
		udelay(1);

		if (netwinder_ds1620_get_data())
			value |= mask;

		mask <<= 1;

		netwinder_ds1620_set_clk(1);
		udelay(1);
	}

	return value;
}

static void ds1620_out(int cmd, int bits, int value)
{
	unsigned long flags;

	netwinder_lock(&flags);
	netwinder_ds1620_set_clk(1);
	netwinder_ds1620_set_data_dir(0);
	netwinder_ds1620_reset();

	udelay(1);

	ds1620_send_bits(8, cmd);
	if (bits)
		ds1620_send_bits(bits, value);

	udelay(1);

	netwinder_ds1620_reset();
	netwinder_unlock(&flags);

	msleep(20);
}

static unsigned int ds1620_in(int cmd, int bits)
{
	unsigned long flags;
	unsigned int value;

	netwinder_lock(&flags);
	netwinder_ds1620_set_clk(1);
	netwinder_ds1620_set_data_dir(0);
	netwinder_ds1620_reset();

	udelay(1);

	ds1620_send_bits(8, cmd);

	netwinder_ds1620_set_data_dir(1);
	value = ds1620_recv_bits(bits);

	netwinder_ds1620_reset();
	netwinder_unlock(&flags);

	return value;
}

static int cvt_9_to_int(unsigned int val)
{
	if (val & 0x100)
		val |= 0xfffffe00;

	return val;
}

static void ds1620_write_state(struct therm *therm)
{
	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
	ds1620_out(THERM_WRITE_TL, 9, therm->lo);
	ds1620_out(THERM_WRITE_TH, 9, therm->hi);
	ds1620_out(THERM_START_CONVERT, 0, 0);
}

static void ds1620_read_state(struct therm *therm)
{
	therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
	therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
}

static int ds1620_open(struct inode *inode, struct file *file)
{
	cycle_kernel_lock();
	return nonseekable_open(inode, file);
}

static ssize_t
ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
{
	signed int cur_temp;
	signed char cur_temp_degF;

	cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;

	/* convert to Fahrenheit, as per wdt.c */
	cur_temp_degF = (cur_temp * 9) / 5 + 32;

	if (copy_to_user(buf, &cur_temp_degF, 1))
		return -EFAULT;

	return 1;
}

static int
ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct therm therm;
	union {
		struct therm __user *therm;
		int __user *i;
	} uarg;
	int i;

	uarg.i = (int __user *)arg;

	switch(cmd) {
	case CMD_SET_THERMOSTATE:
	case CMD_SET_THERMOSTATE2:
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;

		if (cmd == CMD_SET_THERMOSTATE) {
			if (get_user(therm.hi, uarg.i))
				return -EFAULT;
			therm.lo = therm.hi - 3;
		} else {
			if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
				return -EFAULT;
		}

		therm.lo <<= 1;
		therm.hi <<= 1;

		ds1620_write_state(&therm);
		break;

	case CMD_GET_THERMOSTATE:
	case CMD_GET_THERMOSTATE2:
		ds1620_read_state(&therm);

		therm.lo >>= 1;
		therm.hi >>= 1;

		if (cmd == CMD_GET_THERMOSTATE) {
			if (put_user(therm.hi, uarg.i))
				return -EFAULT;
		} else {
			if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
				return -EFAULT;
		}
		break;

	case CMD_GET_TEMPERATURE:
	case CMD_GET_TEMPERATURE2:
		i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));

		if (cmd == CMD_GET_TEMPERATURE)
			i >>= 1;

		return put_user(i, uarg.i) ? -EFAULT : 0;

	case CMD_GET_STATUS:
		i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;

		return put_user(i, uarg.i) ? -EFAULT : 0;

	case CMD_GET_FAN:
		i = netwinder_get_fan();

		return put_user(i, uarg.i) ? -EFAULT : 0;

	case CMD_SET_FAN:
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;

		if (get_user(i, uarg.i))
			return -EFAULT;

		netwinder_set_fan(i);
		break;
		
	default:
		return -ENOIOCTLCMD;
	}

	return 0;
}

static long
ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int ret;

	lock_kernel();
	ret = ds1620_ioctl(file, cmd, arg);
	unlock_kernel();

	return ret;
}

#ifdef THERM_USE_PROC
static int
proc_therm_ds1620_read(char *buf, char **start, off_t offset,
		       int len, int *eof, void *unused)
{
	struct therm th;
	int temp;

	ds1620_read_state(&th);
	temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));

	len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
		      "temperature: %i.%i C, fan %s\n",
		      th.hi >> 1, th.hi & 1 ? 5 : 0,
		      th.lo >> 1, th.lo & 1 ? 5 : 0,
		      temp  >> 1, temp  & 1 ? 5 : 0,
		      fan_state[netwinder_get_fan()]);

	return len;
}

static struct proc_dir_entry *proc_therm_ds1620;
#endif

static const struct file_operations ds1620_fops = {
	.owner		= THIS_MODULE,
	.open		= ds1620_open,
	.read		= ds1620_read,
	.unlocked_ioctl	= ds1620_unlocked_ioctl,
};

static struct miscdevice ds1620_miscdev = {
	TEMP_MINOR,
	"temp",
	&ds1620_fops
};

static int __init ds1620_init(void)
{
	int ret;
	struct therm th, th_start;

	if (!machine_is_netwinder())
		return -ENODEV;

	ds1620_out(THERM_RESET, 0, 0);
	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
	ds1620_out(THERM_START_CONVERT, 0, 0);

	/*
	 * Trigger the fan to start by setting
	 * temperature high point low.  This kicks
	 * the fan into action.
	 */
	ds1620_read_state(&th);
	th_start.lo = 0;
	th_start.hi = 1;
	ds1620_write_state(&th_start);

	msleep(2000);

	ds1620_write_state(&th);

	ret = misc_register(&ds1620_miscdev);
	if (ret < 0)
		return ret;

#ifdef THERM_USE_PROC
	proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
	if (proc_therm_ds1620)
		proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
	else
		printk(KERN_ERR "therm: unable to register /proc/therm\n");
#endif

	ds1620_read_state(&th);
	ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));

	printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
	       "current %i.%i C, fan %s.\n",
	       th.hi >> 1, th.hi & 1 ? 5 : 0,
	       th.lo >> 1, th.lo & 1 ? 5 : 0,
	       ret   >> 1, ret   & 1 ? 5 : 0,
	       fan_state[netwinder_get_fan()]);

	return 0;
}

static void __exit ds1620_exit(void)
{
#ifdef THERM_USE_PROC
	remove_proc_entry("therm", NULL);
#endif
	misc_deregister(&ds1620_miscdev);
}

module_init(ds1620_init);
module_exit(ds1620_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
	3	* thermometer driver (as used in the Rebel.com NetWinder)
	4	*/
1da177e4	5	#include <linux/module.h>
1da177e4	6	#include <linux/miscdevice.h>
1da177e4 LT	7	#include <linux/delay.h>
	8	#include <linux/proc_fs.h>
	9	#include <linux/capability.h>
	10	#include <linux/init.h>
080c2226	11	#include <linux/smp_lock.h>
1da177e4	12
a09e64fb	13	#include <mach/hardware.h>
1da177e4 LT	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
	37	static const char *fan_state[] = { "off", "on", "on (hardwired)" };
	38
	39	/*
	40	* Start of NetWinder specifics
	41	* Note! We have to hold the gpio lock with IRQs disabled over the
	42	* whole of our transaction to the Dallas chip, since there is a
	43	* chance that the WaveArtist driver could touch these bits to
	44	* enable or disable the speaker.
	45	*/
1da177e4 LT	46	extern unsigned int system_rev;
	47
	48	static inline void netwinder_ds1620_set_clk(int clk)
	49	{
70d13e08	50	nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
1da177e4 LT	51	}
	52
	53	static inline void netwinder_ds1620_set_data(int dat)
	54	{
70d13e08	55	nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
1da177e4 LT	56	}
	57
	58	static inline int netwinder_ds1620_get_data(void)
	59	{
70d13e08	60	return nw_gpio_read() & GPIO_DATA;
1da177e4 LT	61	}
	62
	63	static inline void netwinder_ds1620_set_data_dir(int dir)
	64	{
70d13e08	65	nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
1da177e4 LT	66	}
	67
	68	static inline void netwinder_ds1620_reset(void)
	69	{
70d13e08 RK	70	nw_cpld_modify(CPLD_DS_ENABLE, 0);
70d13e08 RK	71	nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
1da177e4 LT	72	}
	73
	74	static inline void netwinder_lock(unsigned long *flags)
	75	{
70d13e08	76	spin_lock_irqsave(&nw_gpio_lock, *flags);
1da177e4 LT	77	}
	78
	79	static inline void netwinder_unlock(unsigned long *flags)
	80	{
70d13e08	81	spin_unlock_irqrestore(&nw_gpio_lock, *flags);
1da177e4 LT	82	}
	83
	84	static inline void netwinder_set_fan(int i)
	85	{
	86	unsigned long flags;
	87
70d13e08 RK	88	spin_lock_irqsave(&nw_gpio_lock, flags);
	89	nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
	90	spin_unlock_irqrestore(&nw_gpio_lock, flags);
1da177e4 LT	91	}
	92
	93	static inline int netwinder_get_fan(void)
	94	{
	95	if ((system_rev & 0xf000) == 0x4000)
	96	return FAN_ALWAYS_ON;
	97
70d13e08	98	return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
1da177e4 LT	99	}
	100
	101	/*
	102	* End of NetWinder specifics
	103	*/
	104
	105	static void ds1620_send_bits(int nr, int value)
	106	{
	107	int i;
	108
	109	for (i = 0; i < nr; i++) {
	110	netwinder_ds1620_set_data(value & 1);
	111	netwinder_ds1620_set_clk(0);
	112	udelay(1);
	113	netwinder_ds1620_set_clk(1);
	114	udelay(1);
	115
	116	value >>= 1;
	117	}
	118	}
	119
	120	static unsigned int ds1620_recv_bits(int nr)
	121	{
	122	unsigned int value = 0, mask = 1;
	123	int i;
	124
	125	netwinder_ds1620_set_data(0);
	126
	127	for (i = 0; i < nr; i++) {
	128	netwinder_ds1620_set_clk(0);
	129	udelay(1);
	130
	131	if (netwinder_ds1620_get_data())
	132	value \|= mask;
	133
	134	mask <<= 1;
	135
	136	netwinder_ds1620_set_clk(1);
	137	udelay(1);
	138	}
	139
	140	return value;
	141	}
	142
	143	static void ds1620_out(int cmd, int bits, int value)
	144	{
	145	unsigned long flags;
	146
	147	netwinder_lock(&flags);
	148	netwinder_ds1620_set_clk(1);
	149	netwinder_ds1620_set_data_dir(0);
	150	netwinder_ds1620_reset();
	151
	152	udelay(1);
	153
	154	ds1620_send_bits(8, cmd);
	155	if (bits)
	156	ds1620_send_bits(bits, value);
	157
	158	udelay(1);
	159
	160	netwinder_ds1620_reset();
	161	netwinder_unlock(&flags);
	162
d8eddb62	163	msleep(20);
1da177e4 LT	164	}
	165
	166	static unsigned int ds1620_in(int cmd, int bits)
	167	{
	168	unsigned long flags;
	169	unsigned int value;
	170
	171	netwinder_lock(&flags);
	172	netwinder_ds1620_set_clk(1);
	173	netwinder_ds1620_set_data_dir(0);
	174	netwinder_ds1620_reset();
	175
	176	udelay(1);
	177
	178	ds1620_send_bits(8, cmd);
	179
	180	netwinder_ds1620_set_data_dir(1);
	181	value = ds1620_recv_bits(bits);
	182
	183	netwinder_ds1620_reset();
	184	netwinder_unlock(&flags);
	185
	186	return value;
	187	}
	188
	189	static int cvt_9_to_int(unsigned int val)
	190	{
	191	if (val & 0x100)
	192	val \|= 0xfffffe00;
	193
	194	return val;
	195	}
	196
	197	static void ds1620_write_state(struct therm *therm)
	198	{
	199	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
	200	ds1620_out(THERM_WRITE_TL, 9, therm->lo);
	201	ds1620_out(THERM_WRITE_TH, 9, therm->hi);
	202	ds1620_out(THERM_START_CONVERT, 0, 0);
	203	}
	204
	205	static void ds1620_read_state(struct therm *therm)
	206	{
	207	therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
	208	therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
	209	}
	210
080c2226 AB	211	static int ds1620_open(struct inode inode, struct file file)
	212	{
	213	cycle_kernel_lock();
	214	return nonseekable_open(inode, file);
	215	}
	216
1da177e4 LT	217	static ssize_t
	218	ds1620_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
	234	static int
55929332	235	ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	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
55929332 AB	319	static long
	320	ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	321	{
	322	int ret;
	323
	324	lock_kernel();
	325	ret = ds1620_ioctl(file, cmd, arg);
	326	unlock_kernel();
	327
	328	return ret;
	329	}
	330
1da177e4 LT	331	#ifdef THERM_USE_PROC
	332	static int
	333	proc_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
	352	static struct proc_dir_entry *proc_therm_ds1620;
	353	#endif
	354
62322d25	355	static const struct file_operations ds1620_fops = {
1da177e4	356	.owner = THIS_MODULE,
080c2226	357	.open = ds1620_open,
1da177e4	358	.read = ds1620_read,
55929332	359	.unlocked_ioctl = ds1620_unlocked_ioctl,
1da177e4 LT	360	};
	361
	362	static struct miscdevice ds1620_miscdev = {
	363	TEMP_MINOR,
	364	"temp",
	365	&ds1620_fops
	366	};
	367
	368	static int __init ds1620_init(void)
	369	{
	370	int ret;
	371	struct therm th, th_start;
	372
	373	if (!machine_is_netwinder())
	374	return -ENODEV;
	375
	376	ds1620_out(THERM_RESET, 0, 0);
	377	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
	378	ds1620_out(THERM_START_CONVERT, 0, 0);
	379
	380	/*
	381	* Trigger the fan to start by setting
	382	* temperature high point low. This kicks
	383	* the fan into action.
	384	*/
	385	ds1620_read_state(&th);
	386	th_start.lo = 0;
	387	th_start.hi = 1;
	388	ds1620_write_state(&th_start);
	389
	390	msleep(2000);
	391
	392	ds1620_write_state(&th);
	393
	394	ret = misc_register(&ds1620_miscdev);
	395	if (ret < 0)
	396	return ret;
	397
	398	#ifdef THERM_USE_PROC
	399	proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
	400	if (proc_therm_ds1620)
	401	proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
	402	else
	403	printk(KERN_ERR "therm: unable to register /proc/therm\n");
	404	#endif
	405
	406	ds1620_read_state(&th);
	407	ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
	408
	409	printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
	410	"current %i.%i C, fan %s.\n",
	411	th.hi >> 1, th.hi & 1 ? 5 : 0,
	412	th.lo >> 1, th.lo & 1 ? 5 : 0,
	413	ret >> 1, ret & 1 ? 5 : 0,
	414	fan_state[netwinder_get_fan()]);
	415
	416	return 0;
	417	}
	418
	419	static void __exit ds1620_exit(void)
	420	{
	421	#ifdef THERM_USE_PROC
	422	remove_proc_entry("therm", NULL);
	423	#endif
424	misc_deregister(&ds1620_miscdev);
425	}
426
427	module_init(ds1620_init);
428	module_exit(ds1620_exit);
429
430	MODULE_LICENSE("GPL");