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therm_windtunnel.c
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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 ([email protected])
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;
52 
53  struct mutex lock;
55 
57  struct i2c_client *fan;
58 
59  int overheat_temp; /* 100% fan at this temp */
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 {
75  int temp;
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)
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,
310  };
311  static const unsigned short scan_adm1030[] = {
312  0x2c, 0x2d, 0x2e, 0x2f,
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 
412 static int
413 do_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
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 
430 static 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 
445 static int therm_of_probe(struct platform_device *dev)
446 {
447  return i2c_add_driver( &g4fan_driver );
448 }
449 
450 static int
451 therm_of_remove( struct platform_device *dev )
452 {
453  i2c_del_driver( &g4fan_driver );
454  return 0;
455 }
456 
457 static const struct of_device_id therm_of_match[] = {{
458  .name = "fan",
459  .compatible = "adm1030"
460  }, {}
461 };
462 
463 static 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 
474  u8 id; /* implementation ID */
475  u8 fan_count; /* number of fans */
476  u8 thermostat_count; /* number of thermostats */
478 };
479 
480 static int __init
481 g4fan_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 
514 static void __exit
515 g4fan_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 
523 module_init(g4fan_init);
524 module_exit(g4fan_exit);
525 
526 MODULE_AUTHOR("Samuel Rydh <[email protected]>");
527 MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
528 MODULE_LICENSE("GPL");