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 <asm/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
38static DEFINE_MUTEX(ds1620_mutex);
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 unsigned int system_rev;
49
50static inline void netwinder_ds1620_set_clk(int clk)
51{
52	nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
53}
54
55static inline void netwinder_ds1620_set_data(int dat)
56{
57	nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
58}
59
60static inline int netwinder_ds1620_get_data(void)
61{
62	return nw_gpio_read() & GPIO_DATA;
63}
64
65static inline void netwinder_ds1620_set_data_dir(int dir)
66{
67	nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
68}
69
70static 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
76static inline void netwinder_lock(unsigned long *flags)
77{
78	raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
79}
80
81static inline void netwinder_unlock(unsigned long *flags)
82{
83	raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
84}
85
86static 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
95static 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
107static 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
122static 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
145static 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
168static 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
191static int cvt_9_to_int(unsigned int val)
192{
193	if (val & 0x100)
194		val |= 0xfffffe00;
195
196	return val;
197}
198
199static 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
207static 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
213static int ds1620_open(struct inode *inode, struct file *file)
214{
215	return nonseekable_open(inode, file);
216}
217
218static ssize_t
219ds1620_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
235static int
236ds1620_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
320static long
321ds1620_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
333static 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
349static int ds1620_proc_therm_open(struct inode *inode, struct file *file)
350{
351	return single_open(file, ds1620_proc_therm_show, NULL);
352}
353
354static const struct file_operations ds1620_proc_therm_fops = {
355	.open		= ds1620_proc_therm_open,
356	.read		= seq_read,
357	.llseek		= seq_lseek,
358	.release	= single_release,
359};
360#endif
361
362static const struct file_operations ds1620_fops = {
363	.owner		= THIS_MODULE,
364	.open		= ds1620_open,
365	.read		= ds1620_read,
366	.unlocked_ioctl	= ds1620_unlocked_ioctl,
367	.llseek		= no_llseek,
368};
369
370static struct miscdevice ds1620_miscdev = {
371	TEMP_MINOR,
372	"temp",
373	&ds1620_fops
374};
375
376static int __init ds1620_init(void)
377{
378	int ret;
379	struct therm th, th_start;
380
381	if (!machine_is_netwinder())
382		return -ENODEV;
383
384	ds1620_out(THERM_RESET, 0, 0);
385	ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
386	ds1620_out(THERM_START_CONVERT, 0, 0);
387
388	/*
389	 * Trigger the fan to start by setting
390	 * temperature high point low.  This kicks
391	 * the fan into action.
392	 */
393	ds1620_read_state(&th);
394	th_start.lo = 0;
395	th_start.hi = 1;
396	ds1620_write_state(&th_start);
397
398	msleep(2000);
399
400	ds1620_write_state(&th);
401
402	ret = misc_register(&ds1620_miscdev);
403	if (ret < 0)
404		return ret;
405
406#ifdef THERM_USE_PROC
407	if (!proc_create("therm", 0, NULL, &ds1620_proc_therm_fops))
408		printk(KERN_ERR "therm: unable to register /proc/therm\n");
409#endif
410
411	ds1620_read_state(&th);
412	ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
413
414	printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
415	       "current %i.%i C, fan %s.\n",
416	       th.hi >> 1, th.hi & 1 ? 5 : 0,
417	       th.lo >> 1, th.lo & 1 ? 5 : 0,
418	       ret   >> 1, ret   & 1 ? 5 : 0,
419	       fan_state[netwinder_get_fan()]);
420
421	return 0;
422}
423
424static void __exit ds1620_exit(void)
425{
426#ifdef THERM_USE_PROC
427	remove_proc_entry("therm", NULL);
428#endif
429	misc_deregister(&ds1620_miscdev);
430}
431
432module_init(ds1620_init);
433module_exit(ds1620_exit);
434
435MODULE_LICENSE("GPL");
436