drm/radeon/kms: enable use of unmappable VRAM V2
[pandora-kernel.git] / drivers / media / common / tuners / mt20xx.c
1 /*
2  * i2c tv tuner chip device driver
3  * controls microtune tuners, mt2032 + mt2050 at the moment.
4  *
5  * This "mt20xx" module was split apart from the original "tuner" module.
6  */
7 #include <linux/delay.h>
8 #include <linux/i2c.h>
9 #include <linux/videodev2.h>
10 #include "tuner-i2c.h"
11 #include "mt20xx.h"
12
13 static int debug;
14 module_param(debug, int, 0644);
15 MODULE_PARM_DESC(debug, "enable verbose debug messages");
16
17 /* ---------------------------------------------------------------------- */
18
19 static unsigned int optimize_vco  = 1;
20 module_param(optimize_vco,      int, 0644);
21
22 static unsigned int tv_antenna    = 1;
23 module_param(tv_antenna,        int, 0644);
24
25 static unsigned int radio_antenna;
26 module_param(radio_antenna,     int, 0644);
27
28 /* ---------------------------------------------------------------------- */
29
30 #define MT2032 0x04
31 #define MT2030 0x06
32 #define MT2040 0x07
33 #define MT2050 0x42
34
35 static char *microtune_part[] = {
36         [ MT2030 ] = "MT2030",
37         [ MT2032 ] = "MT2032",
38         [ MT2040 ] = "MT2040",
39         [ MT2050 ] = "MT2050",
40 };
41
42 struct microtune_priv {
43         struct tuner_i2c_props i2c_props;
44
45         unsigned int xogc;
46         //unsigned int radio_if2;
47
48         u32 frequency;
49 };
50
51 static int microtune_release(struct dvb_frontend *fe)
52 {
53         kfree(fe->tuner_priv);
54         fe->tuner_priv = NULL;
55
56         return 0;
57 }
58
59 static int microtune_get_frequency(struct dvb_frontend *fe, u32 *frequency)
60 {
61         struct microtune_priv *priv = fe->tuner_priv;
62         *frequency = priv->frequency;
63         return 0;
64 }
65
66 // IsSpurInBand()?
67 static int mt2032_spurcheck(struct dvb_frontend *fe,
68                             int f1, int f2, int spectrum_from,int spectrum_to)
69 {
70         struct microtune_priv *priv = fe->tuner_priv;
71         int n1=1,n2,f;
72
73         f1=f1/1000; //scale to kHz to avoid 32bit overflows
74         f2=f2/1000;
75         spectrum_from/=1000;
76         spectrum_to/=1000;
77
78         tuner_dbg("spurcheck f1=%d f2=%d  from=%d to=%d\n",
79                   f1,f2,spectrum_from,spectrum_to);
80
81         do {
82             n2=-n1;
83             f=n1*(f1-f2);
84             do {
85                 n2--;
86                 f=f-f2;
87                 tuner_dbg("spurtest n1=%d n2=%d ftest=%d\n",n1,n2,f);
88
89                 if( (f>spectrum_from) && (f<spectrum_to))
90                         tuner_dbg("mt2032 spurcheck triggered: %d\n",n1);
91             } while ( (f>(f2-spectrum_to)) || (n2>-5));
92             n1++;
93         } while (n1<5);
94
95         return 1;
96 }
97
98 static int mt2032_compute_freq(struct dvb_frontend *fe,
99                                unsigned int rfin,
100                                unsigned int if1, unsigned int if2,
101                                unsigned int spectrum_from,
102                                unsigned int spectrum_to,
103                                unsigned char *buf,
104                                int *ret_sel,
105                                unsigned int xogc) //all in Hz
106 {
107         struct microtune_priv *priv = fe->tuner_priv;
108         unsigned int fref,lo1,lo1n,lo1a,s,sel,lo1freq, desired_lo1,
109                 desired_lo2,lo2,lo2n,lo2a,lo2num,lo2freq;
110
111         fref= 5250 *1000; //5.25MHz
112         desired_lo1=rfin+if1;
113
114         lo1=(2*(desired_lo1/1000)+(fref/1000)) / (2*fref/1000);
115         lo1n=lo1/8;
116         lo1a=lo1-(lo1n*8);
117
118         s=rfin/1000/1000+1090;
119
120         if(optimize_vco) {
121                 if(s>1890) sel=0;
122                 else if(s>1720) sel=1;
123                 else if(s>1530) sel=2;
124                 else if(s>1370) sel=3;
125                 else sel=4; // >1090
126         }
127         else {
128                 if(s>1790) sel=0; // <1958
129                 else if(s>1617) sel=1;
130                 else if(s>1449) sel=2;
131                 else if(s>1291) sel=3;
132                 else sel=4; // >1090
133         }
134         *ret_sel=sel;
135
136         lo1freq=(lo1a+8*lo1n)*fref;
137
138         tuner_dbg("mt2032: rfin=%d lo1=%d lo1n=%d lo1a=%d sel=%d, lo1freq=%d\n",
139                   rfin,lo1,lo1n,lo1a,sel,lo1freq);
140
141         desired_lo2=lo1freq-rfin-if2;
142         lo2=(desired_lo2)/fref;
143         lo2n=lo2/8;
144         lo2a=lo2-(lo2n*8);
145         lo2num=((desired_lo2/1000)%(fref/1000))* 3780/(fref/1000); //scale to fit in 32bit arith
146         lo2freq=(lo2a+8*lo2n)*fref + lo2num*(fref/1000)/3780*1000;
147
148         tuner_dbg("mt2032: rfin=%d lo2=%d lo2n=%d lo2a=%d num=%d lo2freq=%d\n",
149                   rfin,lo2,lo2n,lo2a,lo2num,lo2freq);
150
151         if (lo1a > 7 || lo1n < 17 || lo1n > 48 || lo2a > 7 || lo2n < 17 ||
152                         lo2n > 30) {
153                 tuner_info("mt2032: frequency parameters out of range: %d %d %d %d\n",
154                            lo1a, lo1n, lo2a,lo2n);
155                 return(-1);
156         }
157
158         mt2032_spurcheck(fe, lo1freq, desired_lo2,  spectrum_from, spectrum_to);
159         // should recalculate lo1 (one step up/down)
160
161         // set up MT2032 register map for transfer over i2c
162         buf[0]=lo1n-1;
163         buf[1]=lo1a | (sel<<4);
164         buf[2]=0x86; // LOGC
165         buf[3]=0x0f; //reserved
166         buf[4]=0x1f;
167         buf[5]=(lo2n-1) | (lo2a<<5);
168         if(rfin >400*1000*1000)
169                 buf[6]=0xe4;
170         else
171                 buf[6]=0xf4; // set PKEN per rev 1.2
172         buf[7]=8+xogc;
173         buf[8]=0xc3; //reserved
174         buf[9]=0x4e; //reserved
175         buf[10]=0xec; //reserved
176         buf[11]=(lo2num&0xff);
177         buf[12]=(lo2num>>8) |0x80; // Lo2RST
178
179         return 0;
180 }
181
182 static int mt2032_check_lo_lock(struct dvb_frontend *fe)
183 {
184         struct microtune_priv *priv = fe->tuner_priv;
185         int try,lock=0;
186         unsigned char buf[2];
187
188         for(try=0;try<10;try++) {
189                 buf[0]=0x0e;
190                 tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
191                 tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
192                 tuner_dbg("mt2032 Reg.E=0x%02x\n",buf[0]);
193                 lock=buf[0] &0x06;
194
195                 if (lock==6)
196                         break;
197
198                 tuner_dbg("mt2032: pll wait 1ms for lock (0x%2x)\n",buf[0]);
199                 udelay(1000);
200         }
201         return lock;
202 }
203
204 static int mt2032_optimize_vco(struct dvb_frontend *fe,int sel,int lock)
205 {
206         struct microtune_priv *priv = fe->tuner_priv;
207         unsigned char buf[2];
208         int tad1;
209
210         buf[0]=0x0f;
211         tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
212         tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
213         tuner_dbg("mt2032 Reg.F=0x%02x\n",buf[0]);
214         tad1=buf[0]&0x07;
215
216         if(tad1 ==0) return lock;
217         if(tad1 ==1) return lock;
218
219         if(tad1==2) {
220                 if(sel==0)
221                         return lock;
222                 else sel--;
223         }
224         else {
225                 if(sel<4)
226                         sel++;
227                 else
228                         return lock;
229         }
230
231         tuner_dbg("mt2032 optimize_vco: sel=%d\n",sel);
232
233         buf[0]=0x0f;
234         buf[1]=sel;
235         tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
236         lock=mt2032_check_lo_lock(fe);
237         return lock;
238 }
239
240
241 static void mt2032_set_if_freq(struct dvb_frontend *fe, unsigned int rfin,
242                                unsigned int if1, unsigned int if2,
243                                unsigned int from, unsigned int to)
244 {
245         unsigned char buf[21];
246         int lint_try,ret,sel,lock=0;
247         struct microtune_priv *priv = fe->tuner_priv;
248
249         tuner_dbg("mt2032_set_if_freq rfin=%d if1=%d if2=%d from=%d to=%d\n",
250                   rfin,if1,if2,from,to);
251
252         buf[0]=0;
253         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
254         tuner_i2c_xfer_recv(&priv->i2c_props,buf,21);
255
256         buf[0]=0;
257         ret=mt2032_compute_freq(fe,rfin,if1,if2,from,to,&buf[1],&sel,priv->xogc);
258         if (ret<0)
259                 return;
260
261         // send only the relevant registers per Rev. 1.2
262         buf[0]=0;
263         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,4);
264         buf[5]=5;
265         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+5,4);
266         buf[11]=11;
267         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+11,3);
268         if(ret!=3)
269                 tuner_warn("i2c i/o error: rc == %d (should be 3)\n",ret);
270
271         // wait for PLLs to lock (per manual), retry LINT if not.
272         for(lint_try=0; lint_try<2; lint_try++) {
273                 lock=mt2032_check_lo_lock(fe);
274
275                 if(optimize_vco)
276                         lock=mt2032_optimize_vco(fe,sel,lock);
277                 if(lock==6) break;
278
279                 tuner_dbg("mt2032: re-init PLLs by LINT\n");
280                 buf[0]=7;
281                 buf[1]=0x80 +8+priv->xogc; // set LINT to re-init PLLs
282                 tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
283                 mdelay(10);
284                 buf[1]=8+priv->xogc;
285                 tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
286         }
287
288         if (lock!=6)
289                 tuner_warn("MT2032 Fatal Error: PLLs didn't lock.\n");
290
291         buf[0]=2;
292         buf[1]=0x20; // LOGC for optimal phase noise
293         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
294         if (ret!=2)
295                 tuner_warn("i2c i/o error: rc == %d (should be 2)\n",ret);
296 }
297
298
299 static int mt2032_set_tv_freq(struct dvb_frontend *fe,
300                               struct analog_parameters *params)
301 {
302         int if2,from,to;
303
304         // signal bandwidth and picture carrier
305         if (params->std & V4L2_STD_525_60) {
306                 // NTSC
307                 from = 40750*1000;
308                 to   = 46750*1000;
309                 if2  = 45750*1000;
310         } else {
311                 // PAL
312                 from = 32900*1000;
313                 to   = 39900*1000;
314                 if2  = 38900*1000;
315         }
316
317         mt2032_set_if_freq(fe, params->frequency*62500,
318                            1090*1000*1000, if2, from, to);
319
320         return 0;
321 }
322
323 static int mt2032_set_radio_freq(struct dvb_frontend *fe,
324                                  struct analog_parameters *params)
325 {
326         struct microtune_priv *priv = fe->tuner_priv;
327         int if2;
328
329         if (params->std & V4L2_STD_525_60) {
330                 tuner_dbg("pinnacle ntsc\n");
331                 if2 = 41300 * 1000;
332         } else {
333                 tuner_dbg("pinnacle pal\n");
334                 if2 = 33300 * 1000;
335         }
336
337         // per Manual for FM tuning: first if center freq. 1085 MHz
338         mt2032_set_if_freq(fe, params->frequency * 125 / 2,
339                            1085*1000*1000,if2,if2,if2);
340
341         return 0;
342 }
343
344 static int mt2032_set_params(struct dvb_frontend *fe,
345                              struct analog_parameters *params)
346 {
347         struct microtune_priv *priv = fe->tuner_priv;
348         int ret = -EINVAL;
349
350         switch (params->mode) {
351         case V4L2_TUNER_RADIO:
352                 ret = mt2032_set_radio_freq(fe, params);
353                 priv->frequency = params->frequency * 125 / 2;
354                 break;
355         case V4L2_TUNER_ANALOG_TV:
356         case V4L2_TUNER_DIGITAL_TV:
357                 ret = mt2032_set_tv_freq(fe, params);
358                 priv->frequency = params->frequency * 62500;
359                 break;
360         }
361
362         return ret;
363 }
364
365 static struct dvb_tuner_ops mt2032_tuner_ops = {
366         .set_analog_params = mt2032_set_params,
367         .release           = microtune_release,
368         .get_frequency     = microtune_get_frequency,
369 };
370
371 // Initialization as described in "MT203x Programming Procedures", Rev 1.2, Feb.2001
372 static int mt2032_init(struct dvb_frontend *fe)
373 {
374         struct microtune_priv *priv = fe->tuner_priv;
375         unsigned char buf[21];
376         int ret,xogc,xok=0;
377
378         // Initialize Registers per spec.
379         buf[1]=2; // Index to register 2
380         buf[2]=0xff;
381         buf[3]=0x0f;
382         buf[4]=0x1f;
383         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+1,4);
384
385         buf[5]=6; // Index register 6
386         buf[6]=0xe4;
387         buf[7]=0x8f;
388         buf[8]=0xc3;
389         buf[9]=0x4e;
390         buf[10]=0xec;
391         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+5,6);
392
393         buf[12]=13;  // Index register 13
394         buf[13]=0x32;
395         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+12,2);
396
397         // Adjust XOGC (register 7), wait for XOK
398         xogc=7;
399         do {
400                 tuner_dbg("mt2032: xogc = 0x%02x\n",xogc&0x07);
401                 mdelay(10);
402                 buf[0]=0x0e;
403                 tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
404                 tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
405                 xok=buf[0]&0x01;
406                 tuner_dbg("mt2032: xok = 0x%02x\n",xok);
407                 if (xok == 1) break;
408
409                 xogc--;
410                 tuner_dbg("mt2032: xogc = 0x%02x\n",xogc&0x07);
411                 if (xogc == 3) {
412                         xogc=4; // min. 4 per spec
413                         break;
414                 }
415                 buf[0]=0x07;
416                 buf[1]=0x88 + xogc;
417                 ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
418                 if (ret!=2)
419                         tuner_warn("i2c i/o error: rc == %d (should be 2)\n",ret);
420         } while (xok != 1 );
421         priv->xogc=xogc;
422
423         memcpy(&fe->ops.tuner_ops, &mt2032_tuner_ops, sizeof(struct dvb_tuner_ops));
424
425         return(1);
426 }
427
428 static void mt2050_set_antenna(struct dvb_frontend *fe, unsigned char antenna)
429 {
430         struct microtune_priv *priv = fe->tuner_priv;
431         unsigned char buf[2];
432         int ret;
433
434         buf[0] = 6;
435         buf[1] = antenna ? 0x11 : 0x10;
436         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
437         tuner_dbg("mt2050: enabled antenna connector %d\n", antenna);
438 }
439
440 static void mt2050_set_if_freq(struct dvb_frontend *fe,unsigned int freq, unsigned int if2)
441 {
442         struct microtune_priv *priv = fe->tuner_priv;
443         unsigned int if1=1218*1000*1000;
444         unsigned int f_lo1,f_lo2,lo1,lo2,f_lo1_modulo,f_lo2_modulo,num1,num2,div1a,div1b,div2a,div2b;
445         int ret;
446         unsigned char buf[6];
447
448         tuner_dbg("mt2050_set_if_freq freq=%d if1=%d if2=%d\n",
449                   freq,if1,if2);
450
451         f_lo1=freq+if1;
452         f_lo1=(f_lo1/1000000)*1000000;
453
454         f_lo2=f_lo1-freq-if2;
455         f_lo2=(f_lo2/50000)*50000;
456
457         lo1=f_lo1/4000000;
458         lo2=f_lo2/4000000;
459
460         f_lo1_modulo= f_lo1-(lo1*4000000);
461         f_lo2_modulo= f_lo2-(lo2*4000000);
462
463         num1=4*f_lo1_modulo/4000000;
464         num2=4096*(f_lo2_modulo/1000)/4000;
465
466         // todo spurchecks
467
468         div1a=(lo1/12)-1;
469         div1b=lo1-(div1a+1)*12;
470
471         div2a=(lo2/8)-1;
472         div2b=lo2-(div2a+1)*8;
473
474         if (debug > 1) {
475                 tuner_dbg("lo1 lo2 = %d %d\n", lo1, lo2);
476                 tuner_dbg("num1 num2 div1a div1b div2a div2b= %x %x %x %x %x %x\n",
477                           num1,num2,div1a,div1b,div2a,div2b);
478         }
479
480         buf[0]=1;
481         buf[1]= 4*div1b + num1;
482         if(freq<275*1000*1000) buf[1] = buf[1]|0x80;
483
484         buf[2]=div1a;
485         buf[3]=32*div2b + num2/256;
486         buf[4]=num2-(num2/256)*256;
487         buf[5]=div2a;
488         if(num2!=0) buf[5]=buf[5]|0x40;
489
490         if (debug > 1) {
491                 int i;
492                 tuner_dbg("bufs is: ");
493                 for(i=0;i<6;i++)
494                         printk("%x ",buf[i]);
495                 printk("\n");
496         }
497
498         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,6);
499         if (ret!=6)
500                 tuner_warn("i2c i/o error: rc == %d (should be 6)\n",ret);
501 }
502
503 static int mt2050_set_tv_freq(struct dvb_frontend *fe,
504                               struct analog_parameters *params)
505 {
506         unsigned int if2;
507
508         if (params->std & V4L2_STD_525_60) {
509                 // NTSC
510                 if2 = 45750*1000;
511         } else {
512                 // PAL
513                 if2 = 38900*1000;
514         }
515         if (V4L2_TUNER_DIGITAL_TV == params->mode) {
516                 // DVB (pinnacle 300i)
517                 if2 = 36150*1000;
518         }
519         mt2050_set_if_freq(fe, params->frequency*62500, if2);
520         mt2050_set_antenna(fe, tv_antenna);
521
522         return 0;
523 }
524
525 static int mt2050_set_radio_freq(struct dvb_frontend *fe,
526                                  struct analog_parameters *params)
527 {
528         struct microtune_priv *priv = fe->tuner_priv;
529         int if2;
530
531         if (params->std & V4L2_STD_525_60) {
532                 tuner_dbg("pinnacle ntsc\n");
533                 if2 = 41300 * 1000;
534         } else {
535                 tuner_dbg("pinnacle pal\n");
536                 if2 = 33300 * 1000;
537         }
538
539         mt2050_set_if_freq(fe, params->frequency * 125 / 2, if2);
540         mt2050_set_antenna(fe, radio_antenna);
541
542         return 0;
543 }
544
545 static int mt2050_set_params(struct dvb_frontend *fe,
546                              struct analog_parameters *params)
547 {
548         struct microtune_priv *priv = fe->tuner_priv;
549         int ret = -EINVAL;
550
551         switch (params->mode) {
552         case V4L2_TUNER_RADIO:
553                 ret = mt2050_set_radio_freq(fe, params);
554                 priv->frequency = params->frequency * 125 / 2;
555                 break;
556         case V4L2_TUNER_ANALOG_TV:
557         case V4L2_TUNER_DIGITAL_TV:
558                 ret = mt2050_set_tv_freq(fe, params);
559                 priv->frequency = params->frequency * 62500;
560                 break;
561         }
562
563         return ret;
564 }
565
566 static struct dvb_tuner_ops mt2050_tuner_ops = {
567         .set_analog_params = mt2050_set_params,
568         .release           = microtune_release,
569         .get_frequency     = microtune_get_frequency,
570 };
571
572 static int mt2050_init(struct dvb_frontend *fe)
573 {
574         struct microtune_priv *priv = fe->tuner_priv;
575         unsigned char buf[2];
576         int ret;
577
578         buf[0]=6;
579         buf[1]=0x10;
580         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2); //  power
581
582         buf[0]=0x0f;
583         buf[1]=0x0f;
584         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2); // m1lo
585
586         buf[0]=0x0d;
587         ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
588         tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
589
590         tuner_dbg("mt2050: sro is %x\n",buf[0]);
591
592         memcpy(&fe->ops.tuner_ops, &mt2050_tuner_ops, sizeof(struct dvb_tuner_ops));
593
594         return 0;
595 }
596
597 struct dvb_frontend *microtune_attach(struct dvb_frontend *fe,
598                                       struct i2c_adapter* i2c_adap,
599                                       u8 i2c_addr)
600 {
601         struct microtune_priv *priv = NULL;
602         char *name;
603         unsigned char buf[21];
604         int company_code;
605
606         priv = kzalloc(sizeof(struct microtune_priv), GFP_KERNEL);
607         if (priv == NULL)
608                 return NULL;
609         fe->tuner_priv = priv;
610
611         priv->i2c_props.addr = i2c_addr;
612         priv->i2c_props.adap = i2c_adap;
613         priv->i2c_props.name = "mt20xx";
614
615         //priv->radio_if2 = 10700 * 1000;       /* 10.7MHz - FM radio */
616
617         memset(buf,0,sizeof(buf));
618
619         name = "unknown";
620
621         tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
622         tuner_i2c_xfer_recv(&priv->i2c_props,buf,21);
623         if (debug) {
624                 int i;
625                 tuner_dbg("MT20xx hexdump:");
626                 for(i=0;i<21;i++) {
627                         printk(" %02x",buf[i]);
628                         if(((i+1)%8)==0) printk(" ");
629                 }
630                 printk("\n");
631         }
632         company_code = buf[0x11] << 8 | buf[0x12];
633         tuner_info("microtune: companycode=%04x part=%02x rev=%02x\n",
634                    company_code,buf[0x13],buf[0x14]);
635
636
637         if (buf[0x13] < ARRAY_SIZE(microtune_part) &&
638             NULL != microtune_part[buf[0x13]])
639                 name = microtune_part[buf[0x13]];
640         switch (buf[0x13]) {
641         case MT2032:
642                 mt2032_init(fe);
643                 break;
644         case MT2050:
645                 mt2050_init(fe);
646                 break;
647         default:
648                 tuner_info("microtune %s found, not (yet?) supported, sorry :-/\n",
649                            name);
650                 return NULL;
651         }
652
653         strlcpy(fe->ops.tuner_ops.info.name, name,
654                 sizeof(fe->ops.tuner_ops.info.name));
655         tuner_info("microtune %s found, OK\n",name);
656         return fe;
657 }
658
659 EXPORT_SYMBOL_GPL(microtune_attach);
660
661 MODULE_DESCRIPTION("Microtune tuner driver");
662 MODULE_AUTHOR("Ralph Metzler, Gerd Knorr, Gunther Mayer");
663 MODULE_LICENSE("GPL");
664
665 /*
666  * Overrides for Emacs so that we follow Linus's tabbing style.
667  * ---------------------------------------------------------------------------
668  * Local variables:
669  * c-basic-offset: 8
670  * End:
671  */