1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Device driver for the i2c thermostat found on the iBook G4, Albook G4
4  *
5  * Copyright (C) 2003, 2004 Colin Leroy, Rasmus Rohde, Benjamin Herrenschmidt
6  *
7  * Documentation from 115254175ADT7467_pra.pdf and 3686221171167ADT7460_b.pdf
8  * https://www.onsemi.com/PowerSolutions/product.do?id=ADT7467
9  * https://www.onsemi.com/PowerSolutions/product.do?id=ADT7460
10  *
11  */
12 
13 #include <linux/types.h>
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/kernel.h>
17 #include <linux/delay.h>
18 #include <linux/sched.h>
19 #include <linux/i2c.h>
20 #include <linux/slab.h>
21 #include <linux/init.h>
22 #include <linux/spinlock.h>
23 #include <linux/wait.h>
24 #include <linux/suspend.h>
25 #include <linux/kthread.h>
26 #include <linux/moduleparam.h>
27 #include <linux/freezer.h>
28 #include <linux/of_platform.h>
29 
30 #include <asm/machdep.h>
31 #include <asm/io.h>
32 #include <asm/sections.h>
33 
34 #undef DEBUG
35 
36 #define CONFIG_REG   0x40
37 #define MANUAL_MASK  0xe0
38 #define AUTO_MASK    0x20
39 #define INVERT_MASK  0x10
40 
41 static u8 TEMP_REG[3]    = {0x26, 0x25, 0x27}; /* local, sensor1, sensor2 */
42 static u8 LIMIT_REG[3]   = {0x6b, 0x6a, 0x6c}; /* local, sensor1, sensor2 */
43 static u8 MANUAL_MODE[2] = {0x5c, 0x5d};
44 static u8 REM_CONTROL[2] = {0x00, 0x40};
45 static u8 FAN_SPEED[2]   = {0x28, 0x2a};
46 static u8 FAN_SPD_SET[2] = {0x30, 0x31};
47 
48 static u8 default_limits_local[3] = {70, 50, 70};    /* local, sensor1, sensor2 */
49 static u8 default_limits_chip[3] = {80, 65, 80};    /* local, sensor1, sensor2 */
50 static const char *sensor_location[3] = { "?", "?", "?" };
51 
52 static int limit_adjust;
53 static int fan_speed = -1;
54 static bool verbose;
55 
56 MODULE_AUTHOR("Colin Leroy <colin@colino.net>");
57 MODULE_DESCRIPTION("Driver for ADT746x thermostat in iBook G4 and "
58 		   "Powerbook G4 Alu");
59 MODULE_LICENSE("GPL");
60 
61 module_param(limit_adjust, int, 0644);
62 MODULE_PARM_DESC(limit_adjust,"Adjust maximum temperatures (50 sensor1, 70 sensor2) "
63 		 "by N degrees.");
64 
65 module_param(fan_speed, int, 0644);
66 MODULE_PARM_DESC(fan_speed,"Specify starting fan speed (0-255) "
67 		 "(default 64)");
68 
69 module_param(verbose, bool, 0);
70 MODULE_PARM_DESC(verbose,"Verbose log operations "
71 		 "(default 0)");
72 
73 struct thermostat {
74 	struct i2c_client	*clt;
75 	u8			temps[3];
76 	u8			cached_temp[3];
77 	u8			initial_limits[3];
78 	u8			limits[3];
79 	int			last_speed[2];
80 	int			last_var[2];
81 	int			pwm_inv[2];
82 	struct task_struct	*thread;
83 	struct platform_device	*pdev;
84 	enum {
85 		ADT7460,
86 		ADT7467
87 	}			type;
88 };
89 
90 static void write_both_fan_speed(struct thermostat *th, int speed);
91 static void write_fan_speed(struct thermostat *th, int speed, int fan);
92 
93 static int
94 write_reg(struct thermostat* th, int reg, u8 data)
95 {
96 	u8 tmp[2];
97 	int rc;
98 
99 	tmp[0] = reg;
100 	tmp[1] = data;
101 	rc = i2c_master_send(th->clt, (const char *)tmp, 2);
102 	if (rc < 0)
103 		return rc;
104 	if (rc != 2)
105 		return -ENODEV;
106 	return 0;
107 }
108 
109 static int
110 read_reg(struct thermostat* th, int reg)
111 {
112 	u8 reg_addr, data;
113 	int rc;
114 
115 	reg_addr = (u8)reg;
116 	rc = i2c_master_send(th->clt, &reg_addr, 1);
117 	if (rc < 0)
118 		return rc;
119 	if (rc != 1)
120 		return -ENODEV;
121 	rc = i2c_master_recv(th->clt, (char *)&data, 1);
122 	if (rc < 0)
123 		return rc;
124 	return data;
125 }
126 
127 static int read_fan_speed(struct thermostat *th, u8 addr)
128 {
129 	u8 tmp[2];
130 	u16 res;
131 
132 	/* should start with low byte */
133 	tmp[1] = read_reg(th, addr);
134 	tmp[0] = read_reg(th, addr + 1);
135 
136 	res = tmp[1] + (tmp[0] << 8);
137 	/* "a value of 0xffff means that the fan has stopped" */
138 	return (res == 0xffff ? 0 : (90000*60)/res);
139 }
140 
141 static void write_both_fan_speed(struct thermostat *th, int speed)
142 {
143 	write_fan_speed(th, speed, 0);
144 	if (th->type == ADT7460)
145 		write_fan_speed(th, speed, 1);
146 }
147 
148 static void write_fan_speed(struct thermostat *th, int speed, int fan)
149 {
150 	u8 manual;
151 
152 	if (speed > 0xff)
153 		speed = 0xff;
154 	else if (speed < -1)
155 		speed = 0;
156 
157 	if (th->type == ADT7467 && fan == 1)
158 		return;
159 
160 	if (th->last_speed[fan] != speed) {
161 		if (verbose) {
162 			if (speed == -1)
163 				printk(KERN_DEBUG "adt746x: Setting speed to automatic "
164 					"for %s fan.\n", sensor_location[fan+1]);
165 			else
166 				printk(KERN_DEBUG "adt746x: Setting speed to %d "
167 					"for %s fan.\n", speed, sensor_location[fan+1]);
168 		}
169 	} else
170 		return;
171 
172 	if (speed >= 0) {
173 		manual = read_reg(th, MANUAL_MODE[fan]);
174 		manual &= ~INVERT_MASK;
175 		write_reg(th, MANUAL_MODE[fan],
176 			manual | MANUAL_MASK | th->pwm_inv[fan]);
177 		write_reg(th, FAN_SPD_SET[fan], speed);
178 	} else {
179 		/* back to automatic */
180 		if(th->type == ADT7460) {
181 			manual = read_reg(th,
182 				MANUAL_MODE[fan]) & (~MANUAL_MASK);
183 			manual &= ~INVERT_MASK;
184 			manual |= th->pwm_inv[fan];
185 			write_reg(th,
186 				MANUAL_MODE[fan], manual|REM_CONTROL[fan]);
187 		} else {
188 			manual = read_reg(th, MANUAL_MODE[fan]);
189 			manual &= ~INVERT_MASK;
190 			manual |= th->pwm_inv[fan];
191 			write_reg(th, MANUAL_MODE[fan], manual&(~AUTO_MASK));
192 		}
193 	}
194 
195 	th->last_speed[fan] = speed;
196 }
197 
198 static void read_sensors(struct thermostat *th)
199 {
200 	int i = 0;
201 
202 	for (i = 0; i < 3; i++)
203 		th->temps[i]  = read_reg(th, TEMP_REG[i]);
204 }
205 
206 #ifdef DEBUG
207 static void display_stats(struct thermostat *th)
208 {
209 	if (th->temps[0] != th->cached_temp[0]
210 	||  th->temps[1] != th->cached_temp[1]
211 	||  th->temps[2] != th->cached_temp[2]) {
212 		printk(KERN_INFO "adt746x: Temperature infos:"
213 				 " thermostats: %d,%d,%d;"
214 				 " limits: %d,%d,%d;"
215 				 " fan speed: %d RPM\n",
216 				 th->temps[0], th->temps[1], th->temps[2],
217 				 th->limits[0],  th->limits[1],  th->limits[2],
218 				 read_fan_speed(th, FAN_SPEED[0]));
219 	}
220 	th->cached_temp[0] = th->temps[0];
221 	th->cached_temp[1] = th->temps[1];
222 	th->cached_temp[2] = th->temps[2];
223 }
224 #endif
225 
226 static void update_fans_speed (struct thermostat *th)
227 {
228 	int lastvar = 0; /* last variation, for iBook */
229 	int i = 0;
230 
231 	/* we don't care about local sensor, so we start at sensor 1 */
232 	for (i = 1; i < 3; i++) {
233 		bool started = false;
234 		int fan_number = (th->type == ADT7460 && i == 2);
235 		int var = th->temps[i] - th->limits[i];
236 
237 		if (var > -1) {
238 			int step = (255 - fan_speed) / 7;
239 			int new_speed = 0;
240 
241 			/* hysteresis : change fan speed only if variation is
242 			 * more than two degrees */
243 			if (abs(var - th->last_var[fan_number]) < 2)
244 				continue;
245 
246 			started = true;
247 			new_speed = fan_speed + ((var-1)*step);
248 
249 			if (new_speed < fan_speed)
250 				new_speed = fan_speed;
251 			if (new_speed > 255)
252 				new_speed = 255;
253 
254 			if (verbose)
255 				printk(KERN_DEBUG "adt746x: Setting fans speed to %d "
256 						 "(limit exceeded by %d on %s)\n",
257 						new_speed, var,
258 						sensor_location[fan_number+1]);
259 			write_both_fan_speed(th, new_speed);
260 			th->last_var[fan_number] = var;
261 		} else if (var < -2) {
262 			/* don't stop fan if sensor2 is cold and sensor1 is not
263 			 * so cold (lastvar >= -1) */
264 			if (i == 2 && lastvar < -1) {
265 				if (th->last_speed[fan_number] != 0)
266 					if (verbose)
267 						printk(KERN_DEBUG "adt746x: Stopping "
268 							"fans.\n");
269 				write_both_fan_speed(th, 0);
270 			}
271 		}
272 
273 		lastvar = var;
274 
275 		if (started)
276 			return; /* we don't want to re-stop the fan
277 				* if sensor1 is heating and sensor2 is not */
278 	}
279 }
280 
281 static int monitor_task(void *arg)
282 {
283 	struct thermostat* th = arg;
284 
285 	set_freezable();
286 	while(!kthread_should_stop()) {
287 		try_to_freeze();
288 		msleep_interruptible(2000);
289 
290 #ifndef DEBUG
291 		if (fan_speed != -1)
292 			read_sensors(th);
293 #else
294 		read_sensors(th);
295 #endif
296 
297 		if (fan_speed != -1)
298 			update_fans_speed(th);
299 
300 #ifdef DEBUG
301 		display_stats(th);
302 #endif
303 
304 	}
305 
306 	return 0;
307 }
308 
309 static void set_limit(struct thermostat *th, int i)
310 {
311 	/* Set sensor1 limit higher to avoid powerdowns */
312 	th->limits[i] = default_limits_chip[i] + limit_adjust;
313 	write_reg(th, LIMIT_REG[i], th->limits[i]);
314 
315 	/* set our limits to normal */
316 	th->limits[i] = default_limits_local[i] + limit_adjust;
317 }
318 
319 #define BUILD_SHOW_FUNC_INT(name, data)				\
320 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)	\
321 {								\
322 	struct thermostat *th = dev_get_drvdata(dev);		\
323 	return sprintf(buf, "%d\n", data);			\
324 }
325 
326 #define BUILD_SHOW_FUNC_INT_LITE(name, data)				\
327 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)	\
328 {								\
329 	return sprintf(buf, "%d\n", data);			\
330 }
331 
332 #define BUILD_SHOW_FUNC_STR(name, data)				\
333 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
334 {								\
335 	return sprintf(buf, "%s\n", data);			\
336 }
337 
338 #define BUILD_SHOW_FUNC_FAN(name, data)				\
339 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
340 {								\
341 	struct thermostat *th = dev_get_drvdata(dev);		\
342 	return sprintf(buf, "%d (%d rpm)\n", 			\
343 		th->last_speed[data],				\
344 		read_fan_speed(th, FAN_SPEED[data])		\
345 		);						\
346 }
347 
348 #define BUILD_STORE_FUNC_DEG(name, data)			\
349 static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
350 {								\
351 	struct thermostat *th = dev_get_drvdata(dev);		\
352 	int val;						\
353 	int i;							\
354 	val = simple_strtol(buf, NULL, 10);			\
355 	printk(KERN_INFO "Adjusting limits by %d degrees\n", val);	\
356 	limit_adjust = val;					\
357 	for (i=0; i < 3; i++)					\
358 		set_limit(th, i);				\
359 	return n;						\
360 }
361 
362 #define BUILD_STORE_FUNC_INT(name, data)			\
363 static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
364 {								\
365 	int val;						\
366 	val = simple_strtol(buf, NULL, 10);			\
367 	if (val < 0 || val > 255)				\
368 		return -EINVAL;					\
369 	printk(KERN_INFO "Setting specified fan speed to %d\n", val);	\
370 	data = val;						\
371 	return n;						\
372 }
373 
374 BUILD_SHOW_FUNC_INT(sensor1_temperature,	 (read_reg(th, TEMP_REG[1])))
375 BUILD_SHOW_FUNC_INT(sensor2_temperature,	 (read_reg(th, TEMP_REG[2])))
376 BUILD_SHOW_FUNC_INT(sensor1_limit,		 th->limits[1])
377 BUILD_SHOW_FUNC_INT(sensor2_limit,		 th->limits[2])
378 BUILD_SHOW_FUNC_STR(sensor1_location,		 sensor_location[1])
379 BUILD_SHOW_FUNC_STR(sensor2_location,		 sensor_location[2])
380 
381 BUILD_SHOW_FUNC_INT_LITE(specified_fan_speed, fan_speed)
382 BUILD_STORE_FUNC_INT(specified_fan_speed,fan_speed)
383 
384 BUILD_SHOW_FUNC_FAN(sensor1_fan_speed,	 0)
385 BUILD_SHOW_FUNC_FAN(sensor2_fan_speed,	 1)
386 
387 BUILD_SHOW_FUNC_INT_LITE(limit_adjust,	 limit_adjust)
388 BUILD_STORE_FUNC_DEG(limit_adjust,	 th)
389 
390 static DEVICE_ATTR(sensor1_temperature,	S_IRUGO,
391 		   show_sensor1_temperature,NULL);
392 static DEVICE_ATTR(sensor2_temperature,	S_IRUGO,
393 		   show_sensor2_temperature,NULL);
394 static DEVICE_ATTR(sensor1_limit, S_IRUGO,
395 		   show_sensor1_limit,	NULL);
396 static DEVICE_ATTR(sensor2_limit, S_IRUGO,
397 		   show_sensor2_limit,	NULL);
398 static DEVICE_ATTR(sensor1_location, S_IRUGO,
399 		   show_sensor1_location, NULL);
400 static DEVICE_ATTR(sensor2_location, S_IRUGO,
401 		   show_sensor2_location, NULL);
402 
403 static DEVICE_ATTR(specified_fan_speed,	S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
404 		   show_specified_fan_speed,store_specified_fan_speed);
405 
406 static DEVICE_ATTR(sensor1_fan_speed,	S_IRUGO,
407 		   show_sensor1_fan_speed,	NULL);
408 static DEVICE_ATTR(sensor2_fan_speed,	S_IRUGO,
409 		   show_sensor2_fan_speed,	NULL);
410 
411 static DEVICE_ATTR(limit_adjust,	S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
412 		   show_limit_adjust,	store_limit_adjust);
413 
414 static void thermostat_create_files(struct thermostat *th)
415 {
416 	struct device_node *np = th->clt->dev.of_node;
417 	struct device *dev;
418 	int err;
419 
420 	/* To maintain ABI compatibility with userspace, create
421 	 * the old style platform driver and attach the attributes
422 	 * to it here
423 	 */
424 	th->pdev = of_platform_device_create(np, "temperatures", NULL);
425 	if (!th->pdev)
426 		return;
427 	dev = &th->pdev->dev;
428 	dev_set_drvdata(dev, th);
429 	err = device_create_file(dev, &dev_attr_sensor1_temperature);
430 	err |= device_create_file(dev, &dev_attr_sensor2_temperature);
431 	err |= device_create_file(dev, &dev_attr_sensor1_limit);
432 	err |= device_create_file(dev, &dev_attr_sensor2_limit);
433 	err |= device_create_file(dev, &dev_attr_sensor1_location);
434 	err |= device_create_file(dev, &dev_attr_sensor2_location);
435 	err |= device_create_file(dev, &dev_attr_limit_adjust);
436 	err |= device_create_file(dev, &dev_attr_specified_fan_speed);
437 	err |= device_create_file(dev, &dev_attr_sensor1_fan_speed);
438 	if(th->type == ADT7460)
439 		err |= device_create_file(dev, &dev_attr_sensor2_fan_speed);
440 	if (err)
441 		printk(KERN_WARNING
442 			"Failed to create temperature attribute file(s).\n");
443 }
444 
445 static void thermostat_remove_files(struct thermostat *th)
446 {
447 	struct device *dev;
448 
449 	if (!th->pdev)
450 		return;
451 	dev = &th->pdev->dev;
452 	device_remove_file(dev, &dev_attr_sensor1_temperature);
453 	device_remove_file(dev, &dev_attr_sensor2_temperature);
454 	device_remove_file(dev, &dev_attr_sensor1_limit);
455 	device_remove_file(dev, &dev_attr_sensor2_limit);
456 	device_remove_file(dev, &dev_attr_sensor1_location);
457 	device_remove_file(dev, &dev_attr_sensor2_location);
458 	device_remove_file(dev, &dev_attr_limit_adjust);
459 	device_remove_file(dev, &dev_attr_specified_fan_speed);
460 	device_remove_file(dev, &dev_attr_sensor1_fan_speed);
461 	if (th->type == ADT7460)
462 		device_remove_file(dev, &dev_attr_sensor2_fan_speed);
463 	of_device_unregister(th->pdev);
464 
465 }
466 
467 static int probe_thermostat(struct i2c_client *client)
468 {
469 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
470 	struct device_node *np = client->dev.of_node;
471 	struct thermostat* th;
472 	const __be32 *prop;
473 	int i, rc, vers, offset = 0;
474 
475 	if (!np)
476 		return -ENXIO;
477 	prop = of_get_property(np, "hwsensor-params-version", NULL);
478 	if (!prop)
479 		return -ENXIO;
480 	vers = be32_to_cpup(prop);
481 	printk(KERN_INFO "adt746x: version %d (%ssupported)\n",
482 	       vers, vers == 1 ? "" : "un");
483 	if (vers != 1)
484 		return -ENXIO;
485 
486 	if (of_property_present(np, "hwsensor-location")) {
487 		for (i = 0; i < 3; i++) {
488 			sensor_location[i] = of_get_property(np,
489 					"hwsensor-location", NULL) + offset;
490 
491 			if (sensor_location[i] == NULL)
492 				sensor_location[i] = "";
493 
494 			printk(KERN_INFO "sensor %d: %s\n", i, sensor_location[i]);
495 			offset += strlen(sensor_location[i]) + 1;
496 		}
497 	}
498 
499 	th = kzalloc(sizeof(struct thermostat), GFP_KERNEL);
500 	if (!th)
501 		return -ENOMEM;
502 
503 	i2c_set_clientdata(client, th);
504 	th->clt = client;
505 	th->type = id->driver_data;
506 
507 	rc = read_reg(th, CONFIG_REG);
508 	if (rc < 0) {
509 		dev_err(&client->dev, "Thermostat failed to read config!\n");
510 		kfree(th);
511 		return -ENODEV;
512 	}
513 
514 	/* force manual control to start the fan quieter */
515 	if (fan_speed == -1)
516 		fan_speed = 64;
517 
518 	if (th->type == ADT7460) {
519 		printk(KERN_INFO "adt746x: ADT7460 initializing\n");
520 		/* The 7460 needs to be started explicitly */
521 		write_reg(th, CONFIG_REG, 1);
522 	} else
523 		printk(KERN_INFO "adt746x: ADT7467 initializing\n");
524 
525 	for (i = 0; i < 3; i++) {
526 		th->initial_limits[i] = read_reg(th, LIMIT_REG[i]);
527 		set_limit(th, i);
528 	}
529 
530 	printk(KERN_INFO "adt746x: Lowering max temperatures from %d, %d, %d"
531 			 " to %d, %d, %d\n",
532 			 th->initial_limits[0], th->initial_limits[1],
533 			 th->initial_limits[2], th->limits[0], th->limits[1],
534 			 th->limits[2]);
535 
536 	/* record invert bit status because fw can corrupt it after suspend */
537 	th->pwm_inv[0] = read_reg(th, MANUAL_MODE[0]) & INVERT_MASK;
538 	th->pwm_inv[1] = read_reg(th, MANUAL_MODE[1]) & INVERT_MASK;
539 
540 	/* be sure to really write fan speed the first time */
541 	th->last_speed[0] = -2;
542 	th->last_speed[1] = -2;
543 	th->last_var[0] = -80;
544 	th->last_var[1] = -80;
545 
546 	if (fan_speed != -1) {
547 		/* manual mode, stop fans */
548 		write_both_fan_speed(th, 0);
549 	} else {
550 		/* automatic mode */
551 		write_both_fan_speed(th, -1);
552 	}
553 
554 	th->thread = kthread_run(monitor_task, th, "kfand");
555 	if (th->thread == ERR_PTR(-ENOMEM)) {
556 		printk(KERN_INFO "adt746x: Kthread creation failed\n");
557 		th->thread = NULL;
558 		return -ENOMEM;
559 	}
560 
561 	thermostat_create_files(th);
562 
563 	return 0;
564 }
565 
566 static void remove_thermostat(struct i2c_client *client)
567 {
568 	struct thermostat *th = i2c_get_clientdata(client);
569 	int i;
570 
571 	thermostat_remove_files(th);
572 
573 	if (th->thread != NULL)
574 		kthread_stop(th->thread);
575 
576 	printk(KERN_INFO "adt746x: Putting max temperatures back from "
577 			 "%d, %d, %d to %d, %d, %d\n",
578 		th->limits[0], th->limits[1], th->limits[2],
579 		th->initial_limits[0], th->initial_limits[1],
580 		th->initial_limits[2]);
581 
582 	for (i = 0; i < 3; i++)
583 		write_reg(th, LIMIT_REG[i], th->initial_limits[i]);
584 
585 	write_both_fan_speed(th, -1);
586 
587 	kfree(th);
588 }
589 
590 static const struct i2c_device_id therm_adt746x_id[] = {
591 	{ "MAC,adt7460", ADT7460 },
592 	{ "MAC,adt7467", ADT7467 },
593 	{ }
594 };
595 MODULE_DEVICE_TABLE(i2c, therm_adt746x_id);
596 
597 static struct i2c_driver thermostat_driver = {
598 	.driver = {
599 		.name	= "therm_adt746x",
600 	},
601 	.probe_new = probe_thermostat,
602 	.remove = remove_thermostat,
603 	.id_table = therm_adt746x_id,
604 };
605 
606 static int __init thermostat_init(void)
607 {
608 #ifndef CONFIG_I2C_POWERMAC
609 	request_module("i2c-powermac");
610 #endif
611 
612 	return i2c_add_driver(&thermostat_driver);
613 }
614 
615 static void __exit thermostat_exit(void)
616 {
617 	i2c_del_driver(&thermostat_driver);
618 }
619 
620 module_init(thermostat_init);
621 module_exit(thermostat_exit);
622