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");
425