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_platform.h>
40 
41 #include <asm/prom.h>
42 #include <asm/machdep.h>
43 #include <asm/io.h>
44 #include <asm/sections.h>
45 #include <asm/macio.h>
46 
47 #define LOG_TEMP		0			/* continuously log temperature */
48 
49 static struct {
50 	volatile int		running;
51 	struct task_struct	*poll_task;
52 
53 	struct mutex	 	lock;
54 	struct platform_device	*of_dev;
55 
56 	struct i2c_client	*thermostat;
57 	struct i2c_client	*fan;
58 
59 	int			overheat_temp;		/* 100% fan at this temp */
60 	int			overheat_hyst;
61 	int			temp;
62 	int			casetemp;
63 	int			fan_level;		/* active fan_table setting */
64 
65 	int			downind;
66 	int			upind;
67 
68 	int			r0, r1, r20, r23, r25;	/* saved register */
69 } x;
70 
71 #define T(x,y)			(((x)<<8) | (y)*0x100/10 )
72 
73 static struct {
74 	int			fan_down_setting;
75 	int			temp;
76 	int			fan_up_setting;
77 } fan_table[] = {
78 	{ 11, T(0,0),  11 },	/* min fan */
79 	{ 11, T(55,0), 11 },
80 	{  6, T(55,3), 11 },
81 	{  7, T(56,0), 11 },
82 	{  8, T(57,0), 8 },
83 	{  7, T(58,3), 7 },
84 	{  6, T(58,8), 6 },
85 	{  5, T(59,2), 5 },
86 	{  4, T(59,6), 4 },
87 	{  3, T(59,9), 3 },
88 	{  2, T(60,1), 2 },
89 	{  1, 0xfffff, 1 }	/* on fire */
90 };
91 
92 static void
93 print_temp( const char *s, int temp )
94 {
95 	printk("%s%d.%d C", s ? s : "", temp>>8, (temp & 255)*10/256 );
96 }
97 
98 static ssize_t
99 show_cpu_temperature( struct device *dev, struct device_attribute *attr, char *buf )
100 {
101 	return sprintf(buf, "%d.%d\n", x.temp>>8, (x.temp & 255)*10/256 );
102 }
103 
104 static ssize_t
105 show_case_temperature( struct device *dev, struct device_attribute *attr, char *buf )
106 {
107 	return sprintf(buf, "%d.%d\n", x.casetemp>>8, (x.casetemp & 255)*10/256 );
108 }
109 
110 static DEVICE_ATTR(cpu_temperature, S_IRUGO, show_cpu_temperature, NULL );
111 static DEVICE_ATTR(case_temperature, S_IRUGO, show_case_temperature, NULL );
112 
113 
114 
115 /************************************************************************/
116 /*	controller thread						*/
117 /************************************************************************/
118 
119 static int
120 write_reg( struct i2c_client *cl, int reg, int data, int len )
121 {
122 	u8 tmp[3];
123 
124 	if( len < 1 || len > 2 || data < 0 )
125 		return -EINVAL;
126 
127 	tmp[0] = reg;
128 	tmp[1] = (len == 1) ? data : (data >> 8);
129 	tmp[2] = data;
130 	len++;
131 
132 	if( i2c_master_send(cl, tmp, len) != len )
133 		return -ENODEV;
134 	return 0;
135 }
136 
137 static int
138 read_reg( struct i2c_client *cl, int reg, int len )
139 {
140 	u8 buf[2];
141 
142 	if( len != 1 && len != 2 )
143 		return -EINVAL;
144 	buf[0] = reg;
145 	if( i2c_master_send(cl, buf, 1) != 1 )
146 		return -ENODEV;
147 	if( i2c_master_recv(cl, buf, len) != len )
148 		return -ENODEV;
149 	return (len == 2)? ((unsigned int)buf[0] << 8) | buf[1] : buf[0];
150 }
151 
152 static void
153 tune_fan( int fan_setting )
154 {
155 	int val = (fan_setting << 3) | 7;
156 
157 	/* write_reg( x.fan, 0x24, val, 1 ); */
158 	write_reg( x.fan, 0x25, val, 1 );
159 	write_reg( x.fan, 0x20, 0, 1 );
160 	print_temp("CPU-temp: ", x.temp );
161 	if( x.casetemp )
162 		print_temp(", Case: ", x.casetemp );
163 	printk(",  Fan: %d (tuned %+d)\n", 11-fan_setting, x.fan_level-fan_setting );
164 
165 	x.fan_level = fan_setting;
166 }
167 
168 static void
169 poll_temp( void )
170 {
171 	int temp, i, level, casetemp;
172 
173 	temp = read_reg( x.thermostat, 0, 2 );
174 
175 	/* this actually occurs when the computer is loaded */
176 	if( temp < 0 )
177 		return;
178 
179 	casetemp = read_reg(x.fan, 0x0b, 1) << 8;
180 	casetemp |= (read_reg(x.fan, 0x06, 1) & 0x7) << 5;
181 
182 	if( LOG_TEMP && x.temp != temp ) {
183 		print_temp("CPU-temp: ", temp );
184 		print_temp(", Case: ", casetemp );
185 		printk(",  Fan: %d\n", 11-x.fan_level );
186 	}
187 	x.temp = temp;
188 	x.casetemp = casetemp;
189 
190 	level = -1;
191 	for( i=0; (temp & 0xffff) > fan_table[i].temp ; i++ )
192 		;
193 	if( i < x.downind )
194 		level = fan_table[i].fan_down_setting;
195 	x.downind = i;
196 
197 	for( i=0; (temp & 0xffff) >= fan_table[i+1].temp ; i++ )
198 		;
199 	if( x.upind < i )
200 		level = fan_table[i].fan_up_setting;
201 	x.upind = i;
202 
203 	if( level >= 0 )
204 		tune_fan( level );
205 }
206 
207 
208 static void
209 setup_hardware( void )
210 {
211 	int val;
212 	int err;
213 
214 	/* save registers (if we unload the module) */
215 	x.r0 = read_reg( x.fan, 0x00, 1 );
216 	x.r1 = read_reg( x.fan, 0x01, 1 );
217 	x.r20 = read_reg( x.fan, 0x20, 1 );
218 	x.r23 = read_reg( x.fan, 0x23, 1 );
219 	x.r25 = read_reg( x.fan, 0x25, 1 );
220 
221 	/* improve measurement resolution (convergence time 1.5s) */
222 	if( (val=read_reg(x.thermostat, 1, 1)) >= 0 ) {
223 		val |= 0x60;
224 		if( write_reg( x.thermostat, 1, val, 1 ) )
225 			printk("Failed writing config register\n");
226 	}
227 	/* disable interrupts and TAC input */
228 	write_reg( x.fan, 0x01, 0x01, 1 );
229 	/* enable filter */
230 	write_reg( x.fan, 0x23, 0x91, 1 );
231 	/* remote temp. controls fan */
232 	write_reg( x.fan, 0x00, 0x95, 1 );
233 
234 	/* The thermostat (which besides measureing temperature controls
235 	 * has a THERM output which puts the fan on 100%) is usually
236 	 * set to kick in at 80 C (chip default). We reduce this a bit
237 	 * to be on the safe side (OSX doesn't)...
238 	 */
239 	if( x.overheat_temp == (80 << 8) ) {
240 		x.overheat_temp = 75 << 8;
241 		x.overheat_hyst = 70 << 8;
242 		write_reg( x.thermostat, 2, x.overheat_hyst, 2 );
243 		write_reg( x.thermostat, 3, x.overheat_temp, 2 );
244 
245 		print_temp("Reducing overheating limit to ", x.overheat_temp );
246 		print_temp(" (Hyst: ", x.overheat_hyst );
247 		printk(")\n");
248 	}
249 
250 	/* set an initial fan setting */
251 	x.downind = 0xffff;
252 	x.upind = -1;
253 	/* tune_fan( fan_up_table[x.upind].fan_setting ); */
254 
255 	err = device_create_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
256 	err |= device_create_file( &x.of_dev->dev, &dev_attr_case_temperature );
257 	if (err)
258 		printk(KERN_WARNING
259 			"Failed to create temperature attribute file(s).\n");
260 }
261 
262 static void
263 restore_regs( void )
264 {
265 	device_remove_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
266 	device_remove_file( &x.of_dev->dev, &dev_attr_case_temperature );
267 
268 	write_reg( x.fan, 0x01, x.r1, 1 );
269 	write_reg( x.fan, 0x20, x.r20, 1 );
270 	write_reg( x.fan, 0x23, x.r23, 1 );
271 	write_reg( x.fan, 0x25, x.r25, 1 );
272 	write_reg( x.fan, 0x00, x.r0, 1 );
273 }
274 
275 static int control_loop(void *dummy)
276 {
277 	mutex_lock(&x.lock);
278 	setup_hardware();
279 	mutex_unlock(&x.lock);
280 
281 	for (;;) {
282 		msleep_interruptible(8000);
283 		if (kthread_should_stop())
284 			break;
285 
286 		mutex_lock(&x.lock);
287 		poll_temp();
288 		mutex_unlock(&x.lock);
289 	}
290 
291 	mutex_lock(&x.lock);
292 	restore_regs();
293 	mutex_unlock(&x.lock);
294 
295 	return 0;
296 }
297 
298 
299 /************************************************************************/
300 /*	i2c probing and setup						*/
301 /************************************************************************/
302 
303 static int
304 do_attach( struct i2c_adapter *adapter )
305 {
306 	/* scan 0x48-0x4f (DS1775) and 0x2c-2x2f (ADM1030) */
307 	static const unsigned short scan_ds1775[] = {
308 		0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
309 		I2C_CLIENT_END
310 	};
311 	static const unsigned short scan_adm1030[] = {
312 		0x2c, 0x2d, 0x2e, 0x2f,
313 		I2C_CLIENT_END
314 	};
315 
316 	if( strncmp(adapter->name, "uni-n", 5) )
317 		return 0;
318 
319 	if( !x.running ) {
320 		struct i2c_board_info info;
321 
322 		memset(&info, 0, sizeof(struct i2c_board_info));
323 		strlcpy(info.type, "therm_ds1775", I2C_NAME_SIZE);
324 		i2c_new_probed_device(adapter, &info, scan_ds1775, NULL);
325 
326 		strlcpy(info.type, "therm_adm1030", I2C_NAME_SIZE);
327 		i2c_new_probed_device(adapter, &info, scan_adm1030, NULL);
328 
329 		if( x.thermostat && x.fan ) {
330 			x.running = 1;
331 			x.poll_task = kthread_run(control_loop, NULL, "g4fand");
332 		}
333 	}
334 	return 0;
335 }
336 
337 static int
338 do_remove(struct i2c_client *client)
339 {
340 	if (x.running) {
341 		x.running = 0;
342 		kthread_stop(x.poll_task);
343 		x.poll_task = NULL;
344 	}
345 	if (client == x.thermostat)
346 		x.thermostat = NULL;
347 	else if (client == x.fan)
348 		x.fan = NULL;
349 	else
350 		printk(KERN_ERR "g4fan: bad client\n");
351 
352 	return 0;
353 }
354 
355 static int
356 attach_fan( struct i2c_client *cl )
357 {
358 	if( x.fan )
359 		goto out;
360 
361 	/* check that this is an ADM1030 */
362 	if( read_reg(cl, 0x3d, 1) != 0x30 || read_reg(cl, 0x3e, 1) != 0x41 )
363 		goto out;
364 	printk("ADM1030 fan controller [@%02x]\n", cl->addr );
365 
366 	x.fan = cl;
367  out:
368 	return 0;
369 }
370 
371 static int
372 attach_thermostat( struct i2c_client *cl )
373 {
374 	int hyst_temp, os_temp, temp;
375 
376 	if( x.thermostat )
377 		goto out;
378 
379 	if( (temp=read_reg(cl, 0, 2)) < 0 )
380 		goto out;
381 
382 	/* temperature sanity check */
383 	if( temp < 0x1600 || temp > 0x3c00 )
384 		goto out;
385 	hyst_temp = read_reg(cl, 2, 2);
386 	os_temp = read_reg(cl, 3, 2);
387 	if( hyst_temp < 0 || os_temp < 0 )
388 		goto out;
389 
390 	printk("DS1775 digital thermometer [@%02x]\n", cl->addr );
391 	print_temp("Temp: ", temp );
392 	print_temp("  Hyst: ", hyst_temp );
393 	print_temp("  OS: ", os_temp );
394 	printk("\n");
395 
396 	x.temp = temp;
397 	x.overheat_temp = os_temp;
398 	x.overheat_hyst = hyst_temp;
399 	x.thermostat = cl;
400 out:
401 	return 0;
402 }
403 
404 enum chip { ds1775, adm1030 };
405 
406 static const struct i2c_device_id therm_windtunnel_id[] = {
407 	{ "therm_ds1775", ds1775 },
408 	{ "therm_adm1030", adm1030 },
409 	{ }
410 };
411 MODULE_DEVICE_TABLE(i2c, therm_windtunnel_id);
412 
413 static int
414 do_probe(struct i2c_client *cl, const struct i2c_device_id *id)
415 {
416 	struct i2c_adapter *adapter = cl->adapter;
417 
418 	if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
419 				     | I2C_FUNC_SMBUS_WRITE_BYTE) )
420 		return 0;
421 
422 	switch (id->driver_data) {
423 	case adm1030:
424 		return attach_fan( cl );
425 	case ds1775:
426 		return attach_thermostat(cl);
427 	}
428 	return 0;
429 }
430 
431 static struct i2c_driver g4fan_driver = {
432 	.driver = {
433 		.name	= "therm_windtunnel",
434 	},
435 	.probe		= do_probe,
436 	.remove		= do_remove,
437 	.id_table	= therm_windtunnel_id,
438 };
439 
440 
441 /************************************************************************/
442 /*	initialization / cleanup					*/
443 /************************************************************************/
444 
445 static int therm_of_probe(struct platform_device *dev)
446 {
447 	struct i2c_adapter *adap;
448 	int ret, i = 0;
449 
450 	adap = i2c_get_adapter(0);
451 	if (!adap)
452 		return -EPROBE_DEFER;
453 
454 	ret = i2c_add_driver(&g4fan_driver);
455 	if (ret) {
456 		i2c_put_adapter(adap);
457 		return ret;
458 	}
459 
460 	/* We assume Macs have consecutive I2C bus numbers starting at 0 */
461 	while (adap) {
462 		do_attach(adap);
463 		if (x.running)
464 			return 0;
465 		i2c_put_adapter(adap);
466 		adap = i2c_get_adapter(++i);
467 	}
468 
469 	return -ENODEV;
470 }
471 
472 static int
473 therm_of_remove( struct platform_device *dev )
474 {
475 	i2c_del_driver( &g4fan_driver );
476 	return 0;
477 }
478 
479 static const struct of_device_id therm_of_match[] = {{
480 	.name		= "fan",
481 	.compatible	= "adm1030"
482     }, {}
483 };
484 MODULE_DEVICE_TABLE(of, therm_of_match);
485 
486 static struct platform_driver therm_of_driver = {
487 	.driver = {
488 		.name = "temperature",
489 		.of_match_table = therm_of_match,
490 	},
491 	.probe		= therm_of_probe,
492 	.remove		= therm_of_remove,
493 };
494 
495 struct apple_thermal_info {
496 	u8		id;			/* implementation ID */
497 	u8		fan_count;		/* number of fans */
498 	u8		thermostat_count;	/* number of thermostats */
499 	u8		unused;
500 };
501 
502 static int __init
503 g4fan_init( void )
504 {
505 	const struct apple_thermal_info *info;
506 	struct device_node *np;
507 
508 	mutex_init(&x.lock);
509 
510 	if( !(np=of_find_node_by_name(NULL, "power-mgt")) )
511 		return -ENODEV;
512 	info = of_get_property(np, "thermal-info", NULL);
513 	of_node_put(np);
514 
515 	if( !info || !of_machine_is_compatible("PowerMac3,6") )
516 		return -ENODEV;
517 
518 	if( info->id != 3 ) {
519 		printk(KERN_ERR "therm_windtunnel: unsupported thermal design %d\n", info->id );
520 		return -ENODEV;
521 	}
522 	if( !(np=of_find_node_by_name(NULL, "fan")) )
523 		return -ENODEV;
524 	x.of_dev = of_platform_device_create(np, "temperature", NULL);
525 	of_node_put( np );
526 
527 	if( !x.of_dev ) {
528 		printk(KERN_ERR "Can't register fan controller!\n");
529 		return -ENODEV;
530 	}
531 
532 	platform_driver_register( &therm_of_driver );
533 	return 0;
534 }
535 
536 static void __exit
537 g4fan_exit( void )
538 {
539 	platform_driver_unregister( &therm_of_driver );
540 
541 	if( x.of_dev )
542 		of_device_unregister( x.of_dev );
543 }
544 
545 module_init(g4fan_init);
546 module_exit(g4fan_exit);
547 
548 MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
549 MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
550 MODULE_LICENSE("GPL");
551