aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/media/common/tuners/mt20xx.c
blob: 35b763a16d53748abc5aca07905f70981f576267 (plain) (tree)
1
2
3
4
5
6
7
8
9
  

                                                            

                                                                         


                        
                           


                      
                 


                                                         







                                                                            
                                  















                                                                            
                       

                                         
                          


                                 

  








                                                                           
 


                                                     

 
                  
                                                    

                                                                              
                                                     


























                                                                         
                                                       







                                                                  
                                                     
                                                                   

                                                         
                                   


                                                               

                          
 
                              








                                      




                                          


                     
                                   



                                                                                





                                                                                                



                                                                               

                                                                          

                                                                                      

                           
 
                                                                                








                                                           



                                                    









                                            
                                                        
 
                                                     




                                 

                                                            








                                                                            
                    

 
                                                                        
 
                                                     



                             

                                                    





















                                                       
                                                    
                                      



                    
                                                                          




                                                                  
                                                     



                                                                             
                 

                                                        

                 
                                                                                 


                       

                                                        
                                                        
                 
                                                          
                   
                                                           
                  



                                                                          
                                              

                                
                                                              



                                                            
                                                                      
                                                            
                           
                                    
                                                            
         





                                                                      
                                                        




                                                                          

                                                               
 


                                               
                                            










                                  
                                                       
                                                          

                 

 

                                                                  
 









                                                     

                                                                   



                                                           

 
























                                                              

  
                                                                                    
                                               
 
                                                     

                              

                                         



                                        
                                                          






                                     
                                                          


                                         
                                                           






                                                               

                                                            




                                                        
                                                               





                                                  
                                                                
                           
                                                                                  
                            
                        
 
                                                                                    
 
                  

 
                                                                              
 
                                                     

                             
 

                                       
                                                        
                                                                     

 
                                                                                           
 
                                                     






























                                                                                                     
                        














                                                                                   
                        






                                             
                                                        
                   


                                                                          

                                                               
 

                         
                                            
                       




                                 
                                                    


                                      























                                                                  

 

                                                              
 

                                                     
 












                                                              

 



                                                     

  
                                               
 
                                                     




                             
                                                                  


                    
                                                                

                    

                                                        

                                                
 
                                                                                    
 
                 

 


                                                                   
 
                                           
                   
                              

                         

                                                                  

                              
 

                                        
                                        
 
                                                                        
 
                                  
 

                         

                                                     
                    
                      
                                             





                                                     



                                                                      





                                                     
                                

                      
                                



                                                                                   
                            
         
 

                                                     
                                                    
                  

 





                                                          






                                                                              
/*
 * i2c tv tuner chip device driver
 * controls microtune tuners, mt2032 + mt2050 at the moment.
 *
 * This "mt20xx" module was split apart from the original "tuner" module.
 */
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/videodev.h>
#include "tuner-i2c.h"
#include "mt20xx.h"

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "enable verbose debug messages");

/* ---------------------------------------------------------------------- */

static unsigned int optimize_vco  = 1;
module_param(optimize_vco,      int, 0644);

static unsigned int tv_antenna    = 1;
module_param(tv_antenna,        int, 0644);

static unsigned int radio_antenna;
module_param(radio_antenna,     int, 0644);

/* ---------------------------------------------------------------------- */

#define MT2032 0x04
#define MT2030 0x06
#define MT2040 0x07
#define MT2050 0x42

static char *microtune_part[] = {
	[ MT2030 ] = "MT2030",
	[ MT2032 ] = "MT2032",
	[ MT2040 ] = "MT2040",
	[ MT2050 ] = "MT2050",
};

struct microtune_priv {
	struct tuner_i2c_props i2c_props;

	unsigned int xogc;
	//unsigned int radio_if2;

	u32 frequency;
};

static int microtune_release(struct dvb_frontend *fe)
{
	kfree(fe->tuner_priv);
	fe->tuner_priv = NULL;

	return 0;
}

static int microtune_get_frequency(struct dvb_frontend *fe, u32 *frequency)
{
	struct microtune_priv *priv = fe->tuner_priv;
	*frequency = priv->frequency;
	return 0;
}

// IsSpurInBand()?
static int mt2032_spurcheck(struct dvb_frontend *fe,
			    int f1, int f2, int spectrum_from,int spectrum_to)
{
	struct microtune_priv *priv = fe->tuner_priv;
	int n1=1,n2,f;

	f1=f1/1000; //scale to kHz to avoid 32bit overflows
	f2=f2/1000;
	spectrum_from/=1000;
	spectrum_to/=1000;

	tuner_dbg("spurcheck f1=%d f2=%d  from=%d to=%d\n",
		  f1,f2,spectrum_from,spectrum_to);

	do {
	    n2=-n1;
	    f=n1*(f1-f2);
	    do {
		n2--;
		f=f-f2;
		tuner_dbg("spurtest n1=%d n2=%d ftest=%d\n",n1,n2,f);

		if( (f>spectrum_from) && (f<spectrum_to))
			tuner_dbg("mt2032 spurcheck triggered: %d\n",n1);
	    } while ( (f>(f2-spectrum_to)) || (n2>-5));
	    n1++;
	} while (n1<5);

	return 1;
}

static int mt2032_compute_freq(struct dvb_frontend *fe,
			       unsigned int rfin,
			       unsigned int if1, unsigned int if2,
			       unsigned int spectrum_from,
			       unsigned int spectrum_to,
			       unsigned char *buf,
			       int *ret_sel,
			       unsigned int xogc) //all in Hz
{
	struct microtune_priv *priv = fe->tuner_priv;
	unsigned int fref,lo1,lo1n,lo1a,s,sel,lo1freq, desired_lo1,
		desired_lo2,lo2,lo2n,lo2a,lo2num,lo2freq;

	fref= 5250 *1000; //5.25MHz
	desired_lo1=rfin+if1;

	lo1=(2*(desired_lo1/1000)+(fref/1000)) / (2*fref/1000);
	lo1n=lo1/8;
	lo1a=lo1-(lo1n*8);

	s=rfin/1000/1000+1090;

	if(optimize_vco) {
		if(s>1890) sel=0;
		else if(s>1720) sel=1;
		else if(s>1530) sel=2;
		else if(s>1370) sel=3;
		else sel=4; // >1090
	}
	else {
		if(s>1790) sel=0; // <1958
		else if(s>1617) sel=1;
		else if(s>1449) sel=2;
		else if(s>1291) sel=3;
		else sel=4; // >1090
	}
	*ret_sel=sel;

	lo1freq=(lo1a+8*lo1n)*fref;

	tuner_dbg("mt2032: rfin=%d lo1=%d lo1n=%d lo1a=%d sel=%d, lo1freq=%d\n",
		  rfin,lo1,lo1n,lo1a,sel,lo1freq);

	desired_lo2=lo1freq-rfin-if2;
	lo2=(desired_lo2)/fref;
	lo2n=lo2/8;
	lo2a=lo2-(lo2n*8);
	lo2num=((desired_lo2/1000)%(fref/1000))* 3780/(fref/1000); //scale to fit in 32bit arith
	lo2freq=(lo2a+8*lo2n)*fref + lo2num*(fref/1000)/3780*1000;

	tuner_dbg("mt2032: rfin=%d lo2=%d lo2n=%d lo2a=%d num=%d lo2freq=%d\n",
		  rfin,lo2,lo2n,lo2a,lo2num,lo2freq);

	if (lo1a > 7 || lo1n < 17 || lo1n > 48 || lo2a > 7 || lo2n < 17 ||
			lo2n > 30) {
		tuner_info("mt2032: frequency parameters out of range: %d %d %d %d\n",
			   lo1a, lo1n, lo2a,lo2n);
		return(-1);
	}

	mt2032_spurcheck(fe, lo1freq, desired_lo2,  spectrum_from, spectrum_to);
	// should recalculate lo1 (one step up/down)

	// set up MT2032 register map for transfer over i2c
	buf[0]=lo1n-1;
	buf[1]=lo1a | (sel<<4);
	buf[2]=0x86; // LOGC
	buf[3]=0x0f; //reserved
	buf[4]=0x1f;
	buf[5]=(lo2n-1) | (lo2a<<5);
	if(rfin >400*1000*1000)
		buf[6]=0xe4;
	else
		buf[6]=0xf4; // set PKEN per rev 1.2
	buf[7]=8+xogc;
	buf[8]=0xc3; //reserved
	buf[9]=0x4e; //reserved
	buf[10]=0xec; //reserved
	buf[11]=(lo2num&0xff);
	buf[12]=(lo2num>>8) |0x80; // Lo2RST

	return 0;
}

static int mt2032_check_lo_lock(struct dvb_frontend *fe)
{
	struct microtune_priv *priv = fe->tuner_priv;
	int try,lock=0;
	unsigned char buf[2];

	for(try=0;try<10;try++) {
		buf[0]=0x0e;
		tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
		tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
		tuner_dbg("mt2032 Reg.E=0x%02x\n",buf[0]);
		lock=buf[0] &0x06;

		if (lock==6)
			break;

		tuner_dbg("mt2032: pll wait 1ms for lock (0x%2x)\n",buf[0]);
		udelay(1000);
	}
	return lock;
}

static int mt2032_optimize_vco(struct dvb_frontend *fe,int sel,int lock)
{
	struct microtune_priv *priv = fe->tuner_priv;
	unsigned char buf[2];
	int tad1;

	buf[0]=0x0f;
	tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
	tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
	tuner_dbg("mt2032 Reg.F=0x%02x\n",buf[0]);
	tad1=buf[0]&0x07;

	if(tad1 ==0) return lock;
	if(tad1 ==1) return lock;

	if(tad1==2) {
		if(sel==0)
			return lock;
		else sel--;
	}
	else {
		if(sel<4)
			sel++;
		else
			return lock;
	}

	tuner_dbg("mt2032 optimize_vco: sel=%d\n",sel);

	buf[0]=0x0f;
	buf[1]=sel;
	tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
	lock=mt2032_check_lo_lock(fe);
	return lock;
}


static void mt2032_set_if_freq(struct dvb_frontend *fe, unsigned int rfin,
			       unsigned int if1, unsigned int if2,
			       unsigned int from, unsigned int to)
{
	unsigned char buf[21];
	int lint_try,ret,sel,lock=0;
	struct microtune_priv *priv = fe->tuner_priv;

	tuner_dbg("mt2032_set_if_freq rfin=%d if1=%d if2=%d from=%d to=%d\n",
		  rfin,if1,if2,from,to);

	buf[0]=0;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
	tuner_i2c_xfer_recv(&priv->i2c_props,buf,21);

	buf[0]=0;
	ret=mt2032_compute_freq(fe,rfin,if1,if2,from,to,&buf[1],&sel,priv->xogc);
	if (ret<0)
		return;

	// send only the relevant registers per Rev. 1.2
	buf[0]=0;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,4);
	buf[5]=5;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+5,4);
	buf[11]=11;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+11,3);
	if(ret!=3)
		tuner_warn("i2c i/o error: rc == %d (should be 3)\n",ret);

	// wait for PLLs to lock (per manual), retry LINT if not.
	for(lint_try=0; lint_try<2; lint_try++) {
		lock=mt2032_check_lo_lock(fe);

		if(optimize_vco)
			lock=mt2032_optimize_vco(fe,sel,lock);
		if(lock==6) break;

		tuner_dbg("mt2032: re-init PLLs by LINT\n");
		buf[0]=7;
		buf[1]=0x80 +8+priv->xogc; // set LINT to re-init PLLs
		tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
		mdelay(10);
		buf[1]=8+priv->xogc;
		tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
	}

	if (lock!=6)
		tuner_warn("MT2032 Fatal Error: PLLs didn't lock.\n");

	buf[0]=2;
	buf[1]=0x20; // LOGC for optimal phase noise
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
	if (ret!=2)
		tuner_warn("i2c i/o error: rc == %d (should be 2)\n",ret);
}


static int mt2032_set_tv_freq(struct dvb_frontend *fe,
			      struct analog_parameters *params)
{
	int if2,from,to;

	// signal bandwidth and picture carrier
	if (params->std & V4L2_STD_525_60) {
		// NTSC
		from = 40750*1000;
		to   = 46750*1000;
		if2  = 45750*1000;
	} else {
		// PAL
		from = 32900*1000;
		to   = 39900*1000;
		if2  = 38900*1000;
	}

	mt2032_set_if_freq(fe, params->frequency*62500,
			   1090*1000*1000, if2, from, to);

	return 0;
}

static int mt2032_set_radio_freq(struct dvb_frontend *fe,
				 struct analog_parameters *params)
{
	struct microtune_priv *priv = fe->tuner_priv;
	int if2;

	if (params->std & V4L2_STD_525_60) {
		tuner_dbg("pinnacle ntsc\n");
		if2 = 41300 * 1000;
	} else {
		tuner_dbg("pinnacle pal\n");
		if2 = 33300 * 1000;
	}

	// per Manual for FM tuning: first if center freq. 1085 MHz
	mt2032_set_if_freq(fe, params->frequency * 125 / 2,
			   1085*1000*1000,if2,if2,if2);

	return 0;
}

static int mt2032_set_params(struct dvb_frontend *fe,
			     struct analog_parameters *params)
{
	struct microtune_priv *priv = fe->tuner_priv;
	int ret = -EINVAL;

	switch (params->mode) {
	case V4L2_TUNER_RADIO:
		ret = mt2032_set_radio_freq(fe, params);
		priv->frequency = params->frequency * 125 / 2;
		break;
	case V4L2_TUNER_ANALOG_TV:
	case V4L2_TUNER_DIGITAL_TV:
		ret = mt2032_set_tv_freq(fe, params);
		priv->frequency = params->frequency * 62500;
		break;
	}

	return ret;
}

static struct dvb_tuner_ops mt2032_tuner_ops = {
	.set_analog_params = mt2032_set_params,
	.release           = microtune_release,
	.get_frequency     = microtune_get_frequency,
};

// Initialization as described in "MT203x Programming Procedures", Rev 1.2, Feb.2001
static int mt2032_init(struct dvb_frontend *fe)
{
	struct microtune_priv *priv = fe->tuner_priv;
	unsigned char buf[21];
	int ret,xogc,xok=0;

	// Initialize Registers per spec.
	buf[1]=2; // Index to register 2
	buf[2]=0xff;
	buf[3]=0x0f;
	buf[4]=0x1f;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+1,4);

	buf[5]=6; // Index register 6
	buf[6]=0xe4;
	buf[7]=0x8f;
	buf[8]=0xc3;
	buf[9]=0x4e;
	buf[10]=0xec;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+5,6);

	buf[12]=13;  // Index register 13
	buf[13]=0x32;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf+12,2);

	// Adjust XOGC (register 7), wait for XOK
	xogc=7;
	do {
		tuner_dbg("mt2032: xogc = 0x%02x\n",xogc&0x07);
		mdelay(10);
		buf[0]=0x0e;
		tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
		tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);
		xok=buf[0]&0x01;
		tuner_dbg("mt2032: xok = 0x%02x\n",xok);
		if (xok == 1) break;

		xogc--;
		tuner_dbg("mt2032: xogc = 0x%02x\n",xogc&0x07);
		if (xogc == 3) {
			xogc=4; // min. 4 per spec
			break;
		}
		buf[0]=0x07;
		buf[1]=0x88 + xogc;
		ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
		if (ret!=2)
			tuner_warn("i2c i/o error: rc == %d (should be 2)\n",ret);
	} while (xok != 1 );
	priv->xogc=xogc;

	memcpy(&fe->ops.tuner_ops, &mt2032_tuner_ops, sizeof(struct dvb_tuner_ops));

	return(1);
}

static void mt2050_set_antenna(struct dvb_frontend *fe, unsigned char antenna)
{
	struct microtune_priv *priv = fe->tuner_priv;
	unsigned char buf[2];
	int ret;

	buf[0] = 6;
	buf[1] = antenna ? 0x11 : 0x10;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2);
	tuner_dbg("mt2050: enabled antenna connector %d\n", antenna);
}

static void mt2050_set_if_freq(struct dvb_frontend *fe,unsigned int freq, unsigned int if2)
{
	struct microtune_priv *priv = fe->tuner_priv;
	unsigned int if1=1218*1000*1000;
	unsigned int f_lo1,f_lo2,lo1,lo2,f_lo1_modulo,f_lo2_modulo,num1,num2,div1a,div1b,div2a,div2b;
	int ret;
	unsigned char buf[6];

	tuner_dbg("mt2050_set_if_freq freq=%d if1=%d if2=%d\n",
		  freq,if1,if2);

	f_lo1=freq+if1;
	f_lo1=(f_lo1/1000000)*1000000;

	f_lo2=f_lo1-freq-if2;
	f_lo2=(f_lo2/50000)*50000;

	lo1=f_lo1/4000000;
	lo2=f_lo2/4000000;

	f_lo1_modulo= f_lo1-(lo1*4000000);
	f_lo2_modulo= f_lo2-(lo2*4000000);

	num1=4*f_lo1_modulo/4000000;
	num2=4096*(f_lo2_modulo/1000)/4000;

	// todo spurchecks

	div1a=(lo1/12)-1;
	div1b=lo1-(div1a+1)*12;

	div2a=(lo2/8)-1;
	div2b=lo2-(div2a+1)*8;

	if (debug > 1) {
		tuner_dbg("lo1 lo2 = %d %d\n", lo1, lo2);
		tuner_dbg("num1 num2 div1a div1b div2a div2b= %x %x %x %x %x %x\n",
			  num1,num2,div1a,div1b,div2a,div2b);
	}

	buf[0]=1;
	buf[1]= 4*div1b + num1;
	if(freq<275*1000*1000) buf[1] = buf[1]|0x80;

	buf[2]=div1a;
	buf[3]=32*div2b + num2/256;
	buf[4]=num2-(num2/256)*256;
	buf[5]=div2a;
	if(num2!=0) buf[5]=buf[5]|0x40;

	if (debug > 1) {
		int i;
		tuner_dbg("bufs is: ");
		for(i=0;i<6;i++)
			printk("%x ",buf[i]);
		printk("\n");
	}

	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,6);
	if (ret!=6)
		tuner_warn("i2c i/o error: rc == %d (should be 6)\n",ret);
}

static int mt2050_set_tv_freq(struct dvb_frontend *fe,
			      struct analog_parameters *params)
{
	unsigned int if2;

	if (params->std & V4L2_STD_525_60) {
		// NTSC
		if2 = 45750*1000;
	} else {
		// PAL
		if2 = 38900*1000;
	}
	if (V4L2_TUNER_DIGITAL_TV == params->mode) {
		// DVB (pinnacle 300i)
		if2 = 36150*1000;
	}
	mt2050_set_if_freq(fe, params->frequency*62500, if2);
	mt2050_set_antenna(fe, tv_antenna);

	return 0;
}

static int mt2050_set_radio_freq(struct dvb_frontend *fe,
				 struct analog_parameters *params)
{
	struct microtune_priv *priv = fe->tuner_priv;
	int if2;

	if (params->std & V4L2_STD_525_60) {
		tuner_dbg("pinnacle ntsc\n");
		if2 = 41300 * 1000;
	} else {
		tuner_dbg("pinnacle pal\n");
		if2 = 33300 * 1000;
	}

	mt2050_set_if_freq(fe, params->frequency * 125 / 2, if2);
	mt2050_set_antenna(fe, radio_antenna);

	return 0;
}

static int mt2050_set_params(struct dvb_frontend *fe,
			     struct analog_parameters *params)
{
	struct microtune_priv *priv = fe->tuner_priv;
	int ret = -EINVAL;

	switch (params->mode) {
	case V4L2_TUNER_RADIO:
		ret = mt2050_set_radio_freq(fe, params);
		priv->frequency = params->frequency * 125 / 2;
		break;
	case V4L2_TUNER_ANALOG_TV:
	case V4L2_TUNER_DIGITAL_TV:
		ret = mt2050_set_tv_freq(fe, params);
		priv->frequency = params->frequency * 62500;
		break;
	}

	return ret;
}

static struct dvb_tuner_ops mt2050_tuner_ops = {
	.set_analog_params = mt2050_set_params,
	.release           = microtune_release,
	.get_frequency     = microtune_get_frequency,
};

static int mt2050_init(struct dvb_frontend *fe)
{
	struct microtune_priv *priv = fe->tuner_priv;
	unsigned char buf[2];
	int ret;

	buf[0]=6;
	buf[1]=0x10;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2); //  power

	buf[0]=0x0f;
	buf[1]=0x0f;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,2); // m1lo

	buf[0]=0x0d;
	ret=tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
	tuner_i2c_xfer_recv(&priv->i2c_props,buf,1);

	tuner_dbg("mt2050: sro is %x\n",buf[0]);

	memcpy(&fe->ops.tuner_ops, &mt2050_tuner_ops, sizeof(struct dvb_tuner_ops));

	return 0;
}

struct dvb_frontend *microtune_attach(struct dvb_frontend *fe,
				      struct i2c_adapter* i2c_adap,
				      u8 i2c_addr)
{
	struct microtune_priv *priv = NULL;
	char *name;
	unsigned char buf[21];
	int company_code;

	priv = kzalloc(sizeof(struct microtune_priv), GFP_KERNEL);
	if (priv == NULL)
		return NULL;
	fe->tuner_priv = priv;

	priv->i2c_props.addr = i2c_addr;
	priv->i2c_props.adap = i2c_adap;
	priv->i2c_props.name = "mt20xx";

	//priv->radio_if2 = 10700 * 1000;	/* 10.7MHz - FM radio */

	memset(buf,0,sizeof(buf));

	name = "unknown";

	tuner_i2c_xfer_send(&priv->i2c_props,buf,1);
	tuner_i2c_xfer_recv(&priv->i2c_props,buf,21);
	if (debug) {
		int i;
		tuner_dbg("MT20xx hexdump:");
		for(i=0;i<21;i++) {
			printk(" %02x",buf[i]);
			if(((i+1)%8)==0) printk(" ");
		}
		printk("\n");
	}
	company_code = buf[0x11] << 8 | buf[0x12];
	tuner_info("microtune: companycode=%04x part=%02x rev=%02x\n",
		   company_code,buf[0x13],buf[0x14]);


	if (buf[0x13] < ARRAY_SIZE(microtune_part) &&
	    NULL != microtune_part[buf[0x13]])
		name = microtune_part[buf[0x13]];
	switch (buf[0x13]) {
	case MT2032:
		mt2032_init(fe);
		break;
	case MT2050:
		mt2050_init(fe);
		break;
	default:
		tuner_info("microtune %s found, not (yet?) supported, sorry :-/\n",
			   name);
		return NULL;
	}

	strlcpy(fe->ops.tuner_ops.info.name, name,
		sizeof(fe->ops.tuner_ops.info.name));
	tuner_info("microtune %s found, OK\n",name);
	return fe;
}

EXPORT_SYMBOL_GPL(microtune_attach);

MODULE_DESCRIPTION("Microtune tuner driver");
MODULE_AUTHOR("Ralph Metzler, Gerd Knorr, Gunther Mayer");
MODULE_LICENSE("GPL");

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-basic-offset: 8
 * End:
 */