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
39static 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 */
48extern spinlock_t gpio_lock;
49extern unsigned int system_rev;
50
51static inline void netwinder_ds1620_set_clk(int clk)
52{
53	gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54}
55
56static inline void netwinder_ds1620_set_data(int dat)
57{
58	gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59}
60
61static inline int netwinder_ds1620_get_data(void)
62{
63	return gpio_read() & GPIO_DATA;
64}
65
66static inline void netwinder_ds1620_set_data_dir(int dir)
67{
68	gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69}
70
71static 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
77static inline void netwinder_lock(unsigned long *flags)
78{
79	spin_lock_irqsave(&gpio_lock, *flags);
80}
81
82static inline void netwinder_unlock(unsigned long *flags)
83{
84	spin_unlock_irqrestore(&gpio_lock, *flags);
85}
86
87static 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
96static 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
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	set_current_state(TASK_INTERRUPTIBLE);
167	schedule_timeout(2);
168}
169
170static 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
193static int cvt_9_to_int(unsigned int val)
194{
195	if (val & 0x100)
196		val |= 0xfffffe00;
197
198	return val;
199}
200
201static 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
209static 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
215static ssize_t
216ds1620_read(struct file *file, char *buf, size_t count, loff_t *ptr)
217{
218	signed int cur_temp;
219	signed char cur_temp_degF;
220
221	/* Can't seek (pread) on this device */
222	if (ptr != &file->f_pos)
223		return -ESPIPE;
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 inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
238{
239	struct therm therm;
240	int i;
241
242	switch(cmd) {
243	case CMD_SET_THERMOSTATE:
244	case CMD_SET_THERMOSTATE2:
245		if (!capable(CAP_SYS_ADMIN))
246			return -EPERM;
247
248		if (cmd == CMD_SET_THERMOSTATE) {
249			if (get_user(therm.hi, (int *)arg))
250				return -EFAULT;
251			therm.lo = therm.hi - 3;
252		} else {
253			if (copy_from_user(&therm, (void *)arg, sizeof(therm)))
254				return -EFAULT;
255		}
256
257		therm.lo <<= 1;
258		therm.hi <<= 1;
259
260		ds1620_write_state(&therm);
261		break;
262
263	case CMD_GET_THERMOSTATE:
264	case CMD_GET_THERMOSTATE2:
265		ds1620_read_state(&therm);
266
267		therm.lo >>= 1;
268		therm.hi >>= 1;
269
270		if (cmd == CMD_GET_THERMOSTATE) {
271			if (put_user(therm.hi, (int *)arg))
272				return -EFAULT;
273		} else {
274			if (copy_to_user((void *)arg, &therm, sizeof(therm)))
275				return -EFAULT;
276		}
277		break;
278
279	case CMD_GET_TEMPERATURE:
280	case CMD_GET_TEMPERATURE2:
281		i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
282
283		if (cmd == CMD_GET_TEMPERATURE)
284			i >>= 1;
285
286		return put_user(i, (int *)arg) ? -EFAULT : 0;
287
288	case CMD_GET_STATUS:
289		i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
290
291		return put_user(i, (int *)arg) ? -EFAULT : 0;
292
293	case CMD_GET_FAN:
294		i = netwinder_get_fan();
295
296		return put_user(i, (int *)arg) ? -EFAULT : 0;
297
298	case CMD_SET_FAN:
299		if (!capable(CAP_SYS_ADMIN))
300			return -EPERM;
301
302		if (get_user(i, (int *)arg))
303			return -EFAULT;
304
305		netwinder_set_fan(i);
306		break;
307
308	default:
309		return -ENOIOCTLCMD;
310	}
311
312	return 0;
313}
314
315#ifdef THERM_USE_PROC
316static int
317proc_therm_ds1620_read(char *buf, char **start, off_t offset,
318		       int len, int *eof, void *unused)
319{
320	struct therm th;
321	int temp;
322
323	ds1620_read_state(&th);
324	temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
325
326	len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
327		      "temperature: %i.%i C, fan %s\n",
328		      th.hi >> 1, th.hi & 1 ? 5 : 0,
329		      th.lo >> 1, th.lo & 1 ? 5 : 0,
330		      temp  >> 1, temp  & 1 ? 5 : 0,
331		      fan_state[netwinder_get_fan()]);
332
333	return len;
334}
335
336static struct proc_dir_entry *proc_therm_ds1620;
337#endif
338
339static struct file_operations ds1620_fops = {
340	owner:		THIS_MODULE,
341	read:		ds1620_read,
342	ioctl:		ds1620_ioctl,
343};
344
345static struct miscdevice ds1620_miscdev = {
346	TEMP_MINOR,
347	"temp",
348	&ds1620_fops
349};
350
351int __init ds1620_init(void)
352{
353	int ret;
354	struct therm th, th_start;
355
356	if (!machine_is_netwinder())
357		return -ENODEV;
358
359	ds1620_out(THERM_RESET, 0, 0);
360	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
361	ds1620_out(THERM_START_CONVERT, 0, 0);
362
363	/*
364	 * Trigger the fan to start by setting
365	 * temperature high point low.  This kicks
366	 * the fan into action.
367	 */
368	ds1620_read_state(&th);
369	th_start.lo = 0;
370	th_start.hi = 1;
371	ds1620_write_state(&th_start);
372
373	set_current_state(TASK_INTERRUPTIBLE);
374	schedule_timeout(2*HZ);
375
376	ds1620_write_state(&th);
377
378	ret = misc_register(&ds1620_miscdev);
379	if (ret < 0)
380		return ret;
381
382#ifdef THERM_USE_PROC
383	proc_therm_ds1620 = create_proc_entry("therm", 0, 0);
384	if (proc_therm_ds1620)
385		proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
386	else
387		printk(KERN_ERR "therm: unable to register /proc/therm\n");
388#endif
389
390	ds1620_read_state(&th);
391	ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
392
393	printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
394	       "current %i.%i C, fan %s.\n",
395	       th.hi >> 1, th.hi & 1 ? 5 : 0,
396	       th.lo >> 1, th.lo & 1 ? 5 : 0,
397	       ret   >> 1, ret   & 1 ? 5 : 0,
398	       fan_state[netwinder_get_fan()]);
399
400	return 0;
401}
402
403void __exit ds1620_exit(void)
404{
405#ifdef THERM_USE_PROC
406	remove_proc_entry("therm", NULL);
407#endif
408	misc_deregister(&ds1620_miscdev);
409}
410
411module_init(ds1620_init);
412module_exit(ds1620_exit);
413
414MODULE_LICENSE("GPL");
415