1 /*
2  *   Creation Date: <2003/03/14 20:54:13 samuel>
3  *   Time-stamp: <2004/03/20 14:20:59 samuel>
4  *
5  *	<therm_windtunnel.c>
6  *
7  *	The G4 "windtunnel" has a single fan controlled by an
8  *	ADM1030 fan controller and a DS1775 thermostat.
9  *
10  *	The fan controller is equipped with a temperature sensor
11  *	which measures the case temperature. The DS1775 sensor
12  *	measures the CPU temperature. This driver tunes the
13  *	behavior of the fan. It is based upon empirical observations
14  *	of the 'AppleFan' driver under Mac OS X.
15  *
16  *	WARNING: This driver has only been testen on Apple's
17  *	1.25 MHz Dual G4 (March 03). It is tuned for a CPU
18  *	temperature around 57 C.
19  *
20  *   Copyright (C) 2003, 2004 Samuel Rydh (samuel@ibrium.se)
21  *
22  *   Loosely based upon 'thermostat.c' written by Benjamin Herrenschmidt
23  *
24  *   This program is free software; you can redistribute it and/or
25  *   modify it under the terms of the GNU General Public License
26  *   as published by the Free Software Foundation
27  *
28  */
29 
30 #include <linux/types.h>
31 #include <linux/module.h>
32 #include <linux/errno.h>
33 #include <linux/kernel.h>
34 #include <linux/delay.h>
35 #include <linux/sched.h>
36 #include <linux/i2c.h>
37 #include <linux/init.h>
38 #include <linux/kthread.h>
39 #include <linux/of.h>
40 #include <linux/of_platform.h>
41 #include <linux/platform_device.h>
42 
43 #include <asm/machdep.h>
44 #include <asm/io.h>
45 #include <asm/sections.h>
46 #include <asm/macio.h>
47 
48 #define LOG_TEMP		0			/* continuously log temperature */
49 
50 static struct {
51 	volatile int		running;
52 	struct task_struct	*poll_task;
53 
54 	struct mutex	 	lock;
55 	struct platform_device	*of_dev;
56 
57 	struct i2c_client	*thermostat;
58 	struct i2c_client	*fan;
59 
60 	int			overheat_temp;		/* 100% fan at this temp */
61 	int			overheat_hyst;
62 	int			temp;
63 	int			casetemp;
64 	int			fan_level;		/* active fan_table setting */
65 
66 	int			downind;
67 	int			upind;
68 
69 	int			r0, r1, r20, r23, r25;	/* saved register */
70 } x;
71 
72 #define T(x,y)			(((x)<<8) | (y)*0x100/10 )
73 
74 static struct {
75 	int			fan_down_setting;
76 	int			temp;
77 	int			fan_up_setting;
78 } fan_table[] = {
79 	{ 11, T(0,0),  11 },	/* min fan */
80 	{ 11, T(55,0), 11 },
81 	{  6, T(55,3), 11 },
82 	{  7, T(56,0), 11 },
83 	{  8, T(57,0), 8 },
84 	{  7, T(58,3), 7 },
85 	{  6, T(58,8), 6 },
86 	{  5, T(59,2), 5 },
87 	{  4, T(59,6), 4 },
88 	{  3, T(59,9), 3 },
89 	{  2, T(60,1), 2 },
90 	{  1, 0xfffff, 1 }	/* on fire */
91 };
92 
93 static void
94 print_temp( const char *s, int temp )
95 {
96 	printk("%s%d.%d C", s ? s : "", temp>>8, (temp & 255)*10/256 );
97 }
98 
99 static ssize_t
100 show_cpu_temperature( struct device *dev, struct device_attribute *attr, char *buf )
101 {
102 	return sprintf(buf, "%d.%d\n", x.temp>>8, (x.temp & 255)*10/256 );
103 }
104 
105 static ssize_t
106 show_case_temperature( struct device *dev, struct device_attribute *attr, char *buf )
107 {
108 	return sprintf(buf, "%d.%d\n", x.casetemp>>8, (x.casetemp & 255)*10/256 );
109 }
110 
111 static DEVICE_ATTR(cpu_temperature, S_IRUGO, show_cpu_temperature, NULL );
112 static DEVICE_ATTR(case_temperature, S_IRUGO, show_case_temperature, NULL );
113 
114 
115 
116 /************************************************************************/
117 /*	controller thread						*/
118 /************************************************************************/
119 
120 static int
121 write_reg( struct i2c_client *cl, int reg, int data, int len )
122 {
123 	u8 tmp[3];
124 
125 	if( len < 1 || len > 2 || data < 0 )
126 		return -EINVAL;
127 
128 	tmp[0] = reg;
129 	tmp[1] = (len == 1) ? data : (data >> 8);
130 	tmp[2] = data;
131 	len++;
132 
133 	if( i2c_master_send(cl, tmp, len) != len )
134 		return -ENODEV;
135 	return 0;
136 }
137 
138 static int
139 read_reg( struct i2c_client *cl, int reg, int len )
140 {
141 	u8 buf[2];
142 
143 	if( len != 1 && len != 2 )
144 		return -EINVAL;
145 	buf[0] = reg;
146 	if( i2c_master_send(cl, buf, 1) != 1 )
147 		return -ENODEV;
148 	if( i2c_master_recv(cl, buf, len) != len )
149 		return -ENODEV;
150 	return (len == 2)? ((unsigned int)buf[0] << 8) | buf[1] : buf[0];
151 }
152 
153 static void
154 tune_fan( int fan_setting )
155 {
156 	int val = (fan_setting << 3) | 7;
157 
158 	/* write_reg( x.fan, 0x24, val, 1 ); */
159 	write_reg( x.fan, 0x25, val, 1 );
160 	write_reg( x.fan, 0x20, 0, 1 );
161 	print_temp("CPU-temp: ", x.temp );
162 	if( x.casetemp )
163 		print_temp(", Case: ", x.casetemp );
164 	printk(",  Fan: %d (tuned %+d)\n", 11-fan_setting, x.fan_level-fan_setting );
165 
166 	x.fan_level = fan_setting;
167 }
168 
169 static void
170 poll_temp( void )
171 {
172 	int temp, i, level, casetemp;
173 
174 	temp = read_reg( x.thermostat, 0, 2 );
175 
176 	/* this actually occurs when the computer is loaded */
177 	if( temp < 0 )
178 		return;
179 
180 	casetemp = read_reg(x.fan, 0x0b, 1) << 8;
181 	casetemp |= (read_reg(x.fan, 0x06, 1) & 0x7) << 5;
182 
183 	if( LOG_TEMP && x.temp != temp ) {
184 		print_temp("CPU-temp: ", temp );
185 		print_temp(", Case: ", casetemp );
186 		printk(",  Fan: %d\n", 11-x.fan_level );
187 	}
188 	x.temp = temp;
189 	x.casetemp = casetemp;
190 
191 	level = -1;
192 	for( i=0; (temp & 0xffff) > fan_table[i].temp ; i++ )
193 		;
194 	if( i < x.downind )
195 		level = fan_table[i].fan_down_setting;
196 	x.downind = i;
197 
198 	for( i=0; (temp & 0xffff) >= fan_table[i+1].temp ; i++ )
199 		;
200 	if( x.upind < i )
201 		level = fan_table[i].fan_up_setting;
202 	x.upind = i;
203 
204 	if( level >= 0 )
205 		tune_fan( level );
206 }
207 
208 
209 static void
210 setup_hardware( void )
211 {
212 	int val;
213 	int err;
214 
215 	/* save registers (if we unload the module) */
216 	x.r0 = read_reg( x.fan, 0x00, 1 );
217 	x.r1 = read_reg( x.fan, 0x01, 1 );
218 	x.r20 = read_reg( x.fan, 0x20, 1 );
219 	x.r23 = read_reg( x.fan, 0x23, 1 );
220 	x.r25 = read_reg( x.fan, 0x25, 1 );
221 
222 	/* improve measurement resolution (convergence time 1.5s) */
223 	if( (val=read_reg(x.thermostat, 1, 1)) >= 0 ) {
224 		val |= 0x60;
225 		if( write_reg( x.thermostat, 1, val, 1 ) )
226 			printk("Failed writing config register\n");
227 	}
228 	/* disable interrupts and TAC input */
229 	write_reg( x.fan, 0x01, 0x01, 1 );
230 	/* enable filter */
231 	write_reg( x.fan, 0x23, 0x91, 1 );
232 	/* remote temp. controls fan */
233 	write_reg( x.fan, 0x00, 0x95, 1 );
234 
235 	/* The thermostat (which besides measureing temperature controls
236 	 * has a THERM output which puts the fan on 100%) is usually
237 	 * set to kick in at 80 C (chip default). We reduce this a bit
238 	 * to be on the safe side (OSX doesn't)...
239 	 */
240 	if( x.overheat_temp == (80 << 8) ) {
241 		x.overheat_temp = 75 << 8;
242 		x.overheat_hyst = 70 << 8;
243 		write_reg( x.thermostat, 2, x.overheat_hyst, 2 );
244 		write_reg( x.thermostat, 3, x.overheat_temp, 2 );
245 
246 		print_temp("Reducing overheating limit to ", x.overheat_temp );
247 		print_temp(" (Hyst: ", x.overheat_hyst );
248 		printk(")\n");
249 	}
250 
251 	/* set an initial fan setting */
252 	x.downind = 0xffff;
253 	x.upind = -1;
254 	/* tune_fan( fan_up_table[x.upind].fan_setting ); */
255 
256 	err = device_create_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
257 	err |= device_create_file( &x.of_dev->dev, &dev_attr_case_temperature );
258 	if (err)
259 		printk(KERN_WARNING
260 			"Failed to create temperature attribute file(s).\n");
261 }
262 
263 static void
264 restore_regs( void )
265 {
266 	device_remove_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
267 	device_remove_file( &x.of_dev->dev, &dev_attr_case_temperature );
268 
269 	write_reg( x.fan, 0x01, x.r1, 1 );
270 	write_reg( x.fan, 0x20, x.r20, 1 );
271 	write_reg( x.fan, 0x23, x.r23, 1 );
272 	write_reg( x.fan, 0x25, x.r25, 1 );
273 	write_reg( x.fan, 0x00, x.r0, 1 );
274 }
275 
276 static int control_loop(void *dummy)
277 {
278 	mutex_lock(&x.lock);
279 	setup_hardware();
280 	mutex_unlock(&x.lock);
281 
282 	for (;;) {
283 		msleep_interruptible(8000);
284 		if (kthread_should_stop())
285 			break;
286 
287 		mutex_lock(&x.lock);
288 		poll_temp();
289 		mutex_unlock(&x.lock);
290 	}
291 
292 	mutex_lock(&x.lock);
293 	restore_regs();
294 	mutex_unlock(&x.lock);
295 
296 	return 0;
297 }
298 
299 
300 /************************************************************************/
301 /*	i2c probing and setup						*/
302 /************************************************************************/
303 
304 static void do_attach(struct i2c_adapter *adapter)
305 {
306 	struct i2c_board_info info = { };
307 	struct device_node *np;
308 
309 	/* scan 0x48-0x4f (DS1775) and 0x2c-2x2f (ADM1030) */
310 	static const unsigned short scan_ds1775[] = {
311 		0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
312 		I2C_CLIENT_END
313 	};
314 	static const unsigned short scan_adm1030[] = {
315 		0x2c, 0x2d, 0x2e, 0x2f,
316 		I2C_CLIENT_END
317 	};
318 
319 	if (x.running || strncmp(adapter->name, "uni-n", 5))
320 		return;
321 
322 	of_node_get(adapter->dev.of_node);
323 	np = of_find_compatible_node(adapter->dev.of_node, NULL, "MAC,ds1775");
324 	if (np) {
325 		of_node_put(np);
326 	} else {
327 		strscpy(info.type, "MAC,ds1775", I2C_NAME_SIZE);
328 		i2c_new_scanned_device(adapter, &info, scan_ds1775, NULL);
329 	}
330 
331 	of_node_get(adapter->dev.of_node);
332 	np = of_find_compatible_node(adapter->dev.of_node, NULL, "MAC,adm1030");
333 	if (np) {
334 		of_node_put(np);
335 	} else {
336 		strscpy(info.type, "MAC,adm1030", I2C_NAME_SIZE);
337 		i2c_new_scanned_device(adapter, &info, scan_adm1030, NULL);
338 	}
339 }
340 
341 static void
342 do_remove(struct i2c_client *client)
343 {
344 	if (x.running) {
345 		x.running = 0;
346 		kthread_stop(x.poll_task);
347 		x.poll_task = NULL;
348 	}
349 	if (client == x.thermostat)
350 		x.thermostat = NULL;
351 	else if (client == x.fan)
352 		x.fan = NULL;
353 	else
354 		printk(KERN_ERR "g4fan: bad client\n");
355 }
356 
357 static int
358 attach_fan( struct i2c_client *cl )
359 {
360 	if( x.fan )
361 		goto out;
362 
363 	/* check that this is an ADM1030 */
364 	if( read_reg(cl, 0x3d, 1) != 0x30 || read_reg(cl, 0x3e, 1) != 0x41 )
365 		goto out;
366 	printk("ADM1030 fan controller [@%02x]\n", cl->addr );
367 
368 	x.fan = cl;
369  out:
370 	return 0;
371 }
372 
373 static int
374 attach_thermostat( struct i2c_client *cl )
375 {
376 	int hyst_temp, os_temp, temp;
377 
378 	if( x.thermostat )
379 		goto out;
380 
381 	if( (temp=read_reg(cl, 0, 2)) < 0 )
382 		goto out;
383 
384 	/* temperature sanity check */
385 	if( temp < 0x1600 || temp > 0x3c00 )
386 		goto out;
387 	hyst_temp = read_reg(cl, 2, 2);
388 	os_temp = read_reg(cl, 3, 2);
389 	if( hyst_temp < 0 || os_temp < 0 )
390 		goto out;
391 
392 	printk("DS1775 digital thermometer [@%02x]\n", cl->addr );
393 	print_temp("Temp: ", temp );
394 	print_temp("  Hyst: ", hyst_temp );
395 	print_temp("  OS: ", os_temp );
396 	printk("\n");
397 
398 	x.temp = temp;
399 	x.overheat_temp = os_temp;
400 	x.overheat_hyst = hyst_temp;
401 	x.thermostat = cl;
402 out:
403 	return 0;
404 }
405 
406 enum chip { ds1775, adm1030 };
407 
408 static const struct i2c_device_id therm_windtunnel_id[] = {
409 	{ "MAC,ds1775", ds1775 },
410 	{ "MAC,adm1030", adm1030 },
411 	{ }
412 };
413 MODULE_DEVICE_TABLE(i2c, therm_windtunnel_id);
414 
415 static int
416 do_probe(struct i2c_client *cl)
417 {
418 	const struct i2c_device_id *id = i2c_client_get_device_id(cl);
419 	struct i2c_adapter *adapter = cl->adapter;
420 	int ret = 0;
421 
422 	if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
423 				     | I2C_FUNC_SMBUS_WRITE_BYTE) )
424 		return 0;
425 
426 	switch (id->driver_data) {
427 	case adm1030:
428 		ret = attach_fan(cl);
429 		break;
430 	case ds1775:
431 		ret = attach_thermostat(cl);
432 		break;
433 	}
434 
435 	if (!x.running && x.thermostat && x.fan) {
436 		x.running = 1;
437 		x.poll_task = kthread_run(control_loop, NULL, "g4fand");
438 	}
439 
440 	return ret;
441 }
442 
443 static struct i2c_driver g4fan_driver = {
444 	.driver = {
445 		.name	= "therm_windtunnel",
446 	},
447 	.probe		= do_probe,
448 	.remove		= do_remove,
449 	.id_table	= therm_windtunnel_id,
450 };
451 
452 
453 /************************************************************************/
454 /*	initialization / cleanup					*/
455 /************************************************************************/
456 
457 static int therm_of_probe(struct platform_device *dev)
458 {
459 	struct i2c_adapter *adap;
460 	int ret, i = 0;
461 
462 	adap = i2c_get_adapter(0);
463 	if (!adap)
464 		return -EPROBE_DEFER;
465 
466 	ret = i2c_add_driver(&g4fan_driver);
467 	if (ret) {
468 		i2c_put_adapter(adap);
469 		return ret;
470 	}
471 
472 	/* We assume Macs have consecutive I2C bus numbers starting at 0 */
473 	while (adap) {
474 		do_attach(adap);
475 		if (x.running)
476 			return 0;
477 		i2c_put_adapter(adap);
478 		adap = i2c_get_adapter(++i);
479 	}
480 
481 	return -ENODEV;
482 }
483 
484 static int
485 therm_of_remove( struct platform_device *dev )
486 {
487 	i2c_del_driver( &g4fan_driver );
488 	return 0;
489 }
490 
491 static const struct of_device_id therm_of_match[] = {{
492 	.name		= "fan",
493 	.compatible	= "adm1030"
494     }, {}
495 };
496 MODULE_DEVICE_TABLE(of, therm_of_match);
497 
498 static struct platform_driver therm_of_driver = {
499 	.driver = {
500 		.name = "temperature",
501 		.of_match_table = therm_of_match,
502 	},
503 	.probe		= therm_of_probe,
504 	.remove		= therm_of_remove,
505 };
506 
507 struct apple_thermal_info {
508 	u8		id;			/* implementation ID */
509 	u8		fan_count;		/* number of fans */
510 	u8		thermostat_count;	/* number of thermostats */
511 	u8		unused;
512 };
513 
514 static int __init
515 g4fan_init( void )
516 {
517 	const struct apple_thermal_info *info;
518 	struct device_node *np;
519 
520 	mutex_init(&x.lock);
521 
522 	if( !(np=of_find_node_by_name(NULL, "power-mgt")) )
523 		return -ENODEV;
524 	info = of_get_property(np, "thermal-info", NULL);
525 	of_node_put(np);
526 
527 	if( !info || !of_machine_is_compatible("PowerMac3,6") )
528 		return -ENODEV;
529 
530 	if( info->id != 3 ) {
531 		printk(KERN_ERR "therm_windtunnel: unsupported thermal design %d\n", info->id );
532 		return -ENODEV;
533 	}
534 	if( !(np=of_find_node_by_name(NULL, "fan")) )
535 		return -ENODEV;
536 	x.of_dev = of_platform_device_create(np, "temperature", NULL);
537 	of_node_put( np );
538 
539 	if( !x.of_dev ) {
540 		printk(KERN_ERR "Can't register fan controller!\n");
541 		return -ENODEV;
542 	}
543 
544 	platform_driver_register( &therm_of_driver );
545 	return 0;
546 }
547 
548 static void __exit
549 g4fan_exit( void )
550 {
551 	platform_driver_unregister( &therm_of_driver );
552 
553 	if( x.of_dev )
554 		of_device_unregister( x.of_dev );
555 }
556 
557 module_init(g4fan_init);
558 module_exit(g4fan_exit);
559 
560 MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
561 MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
562 MODULE_LICENSE("GPL");
563