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
49static 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
73static 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
92static void
93print_temp( const char *s, int temp )
94{
95	printk("%s%d.%d C", s ? s : "", temp>>8, (temp & 255)*10/256 );
96}
97
98static ssize_t
99show_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
104static ssize_t
105show_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
110static DEVICE_ATTR(cpu_temperature, S_IRUGO, show_cpu_temperature, NULL );
111static DEVICE_ATTR(case_temperature, S_IRUGO, show_case_temperature, NULL );
112
113
114
115/************************************************************************/
116/*	controller thread						*/
117/************************************************************************/
118
119static int
120write_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
137static int
138read_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
152static void
153tune_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
168static void
169poll_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
208static void
209setup_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
262static void
263restore_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
275static 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
303static int
304do_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
337static int
338do_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
355static int
356attach_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
371static int
372attach_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;
400out:
401	return 0;
402}
403
404enum chip { ds1775, adm1030 };
405
406static const struct i2c_device_id therm_windtunnel_id[] = {
407	{ "therm_ds1775", ds1775 },
408	{ "therm_adm1030", adm1030 },
409	{ }
410};
411
412static int
413do_probe(struct i2c_client *cl, const struct i2c_device_id *id)
414{
415	struct i2c_adapter *adapter = cl->adapter;
416
417	if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
418				     | I2C_FUNC_SMBUS_WRITE_BYTE) )
419		return 0;
420
421	switch (id->driver_data) {
422	case adm1030:
423		return attach_fan( cl );
424	case ds1775:
425		return attach_thermostat(cl);
426	}
427	return 0;
428}
429
430static struct i2c_driver g4fan_driver = {
431	.driver = {
432		.name	= "therm_windtunnel",
433	},
434	.attach_adapter = do_attach,
435	.probe		= do_probe,
436	.remove		= do_remove,
437	.id_table	= therm_windtunnel_id,
438};
439
440
441/************************************************************************/
442/*	initialization / cleanup					*/
443/************************************************************************/
444
445static int therm_of_probe(struct platform_device *dev)
446{
447	return i2c_add_driver( &g4fan_driver );
448}
449
450static int
451therm_of_remove( struct platform_device *dev )
452{
453	i2c_del_driver( &g4fan_driver );
454	return 0;
455}
456
457static const struct of_device_id therm_of_match[] = {{
458	.name		= "fan",
459	.compatible	= "adm1030"
460    }, {}
461};
462
463static struct platform_driver therm_of_driver = {
464	.driver = {
465		.name = "temperature",
466		.owner = THIS_MODULE,
467		.of_match_table = therm_of_match,
468	},
469	.probe		= therm_of_probe,
470	.remove		= therm_of_remove,
471};
472
473struct apple_thermal_info {
474	u8		id;			/* implementation ID */
475	u8		fan_count;		/* number of fans */
476	u8		thermostat_count;	/* number of thermostats */
477	u8		unused;
478};
479
480static int __init
481g4fan_init( void )
482{
483	const struct apple_thermal_info *info;
484	struct device_node *np;
485
486	mutex_init(&x.lock);
487
488	if( !(np=of_find_node_by_name(NULL, "power-mgt")) )
489		return -ENODEV;
490	info = of_get_property(np, "thermal-info", NULL);
491	of_node_put(np);
492
493	if( !info || !of_machine_is_compatible("PowerMac3,6") )
494		return -ENODEV;
495
496	if( info->id != 3 ) {
497		printk(KERN_ERR "therm_windtunnel: unsupported thermal design %d\n", info->id );
498		return -ENODEV;
499	}
500	if( !(np=of_find_node_by_name(NULL, "fan")) )
501		return -ENODEV;
502	x.of_dev = of_platform_device_create(np, "temperature", NULL);
503	of_node_put( np );
504
505	if( !x.of_dev ) {
506		printk(KERN_ERR "Can't register fan controller!\n");
507		return -ENODEV;
508	}
509
510	platform_driver_register( &therm_of_driver );
511	return 0;
512}
513
514static void __exit
515g4fan_exit( void )
516{
517	platform_driver_unregister( &therm_of_driver );
518
519	if( x.of_dev )
520		of_device_unregister( x.of_dev );
521}
522
523module_init(g4fan_init);
524module_exit(g4fan_exit);
525
526MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
527MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
528MODULE_LICENSE("GPL");
529