radio-terratec.c

讲述linux的初始化过程

/* Terratec ActiveRadio ISA Standalone card driver for Linux radio support
 * (c) 1999 R. Offermanns ([e-mail])
 * based on the aimslab radio driver from M. Kirkwood
 * many thanks to Michael Becker and Friedhelm Birth (from TerraTec)
 * 
 *
 * History:
 * 1999-05-21	First preview release
 * 
 *  Notes on the hardware:
 *  There are two "main" chips on the card:
 *  - Philips OM5610 (http://www-us.semiconductors.philips.com/acrobat/datasheets/OM5610_2.pdf)
 *  - Philips SAA6588 (http://www-us.semiconductors.philips.com/acrobat/datasheets/SAA6588_1.pdf)
 *  (you can get the datasheet at the above links)
 *
 *  Frequency control is done digitally -- ie out(port,encodefreq(95.8));
 *  Volume Control is done digitally
 *
 *  there is a I2C controlled RDS decoder (SAA6588)  onboard, which i would like to support someday
 *  (as soon i have understand how to get started :)
 *  If you can help me out with that, please contact me!!
 *
 *  
 */

#include <linux/module.h>	/* Modules 			*/
#include <linux/init.h>		/* Initdata			*/
#include <linux/ioport.h>	/* check_region, request_region	*/
#include <linux/delay.h>	/* udelay			*/
#include <asm/io.h>		/* outb, outb_p			*/
#include <asm/uaccess.h>	/* copy to/from user		*/
#include <linux/videodev.h>	/* kernel radio structs		*/
#include <linux/config.h>	/* CONFIG_RADIO_TERRATEC_PORT 	*/
#include <linux/spinlock.h>

#ifndef CONFIG_RADIO_TERRATEC_PORT
#define CONFIG_RADIO_TERRATEC_PORT 0x590
#endif

/**************** this ones are for the terratec *******************/
#define BASEPORT 	0x590
#define VOLPORT 	0x591
#define WRT_DIS 	0x00
#define CLK_OFF		0x00
#define IIC_DATA	0x01
#define IIC_CLK		0x02
#define DATA		0x04
#define CLK_ON 		0x08
#define WRT_EN		0x10
/*******************************************************************/

static int io = CONFIG_RADIO_TERRATEC_PORT; 
static int users = 0;
static spinlock_t lock;

struct tt_device
{
	int port;
	int curvol;
	unsigned long curfreq;
	int muted;
};


/* local things */

static void cardWriteVol(int volume)
{
	int i;
	volume = volume+(volume * 32); // change both channels
	spin_lock(&lock);
	for (i=0;i<8;i++)
	{
		if (volume & (0x80>>i))
			outb(0x80, VOLPORT);
		else outb(0x00, VOLPORT);
	}
	spin_unlock(&lock);
}



static void tt_mute(struct tt_device *dev)
{
	dev->muted = 1;
	cardWriteVol(0);
}

static int tt_setvol(struct tt_device *dev, int vol)
{
	
//	printk(KERN_ERR "setvol called, vol = %d\n", vol);

	if(vol == dev->curvol) {	/* requested volume = current */
		if (dev->muted) {	/* user is unmuting the card  */
			dev->muted = 0;
			cardWriteVol(vol);	/* enable card */
		}	
	
		return 0;
	}

	if(vol == 0) {			/* volume = 0 means mute the card */
		cardWriteVol(0);	/* "turn off card" by setting vol to 0 */
		dev->curvol = vol;	/* track the volume state!	*/
		return 0;
	}

	dev->muted = 0;
	
	cardWriteVol(vol);
	 
	dev->curvol = vol;

	return 0;

}


/* this is the worst part in this driver */
/* many more or less strange things are going on here, but hey, it works :) */

static int tt_setfreq(struct tt_device *dev, unsigned long freq1)
{	
	int freq;
	int i;
	int p;
	int  temp;
	long rest;
     
	unsigned char buffer[25];		/* we have to bit shift 25 registers */
	freq = freq1/160;			/* convert the freq. to a nice to handel value */
	for(i=24;i>-1;i--)
		buffer[i]=0;

	rest = freq*10+10700;		/* i once had understood what is going on here */
					/* maybe some wise guy (friedhelm?) can comment this stuff */
	i=13;
	p=10;
	temp=102400;
	while (rest!=0)
	{
		if (rest%temp  == rest)
			buffer[i] = 0;
		else 
		{
			buffer[i] = 1; 
			rest = rest-temp;
		}
		i--;
		p--;
		temp = temp/2;
       }

	spin_lock(&lock);
	
	for (i=24;i>-1;i--)			/* bit shift the values to the radiocard */
	{
		if (buffer[i]==1) 
		{
			outb(WRT_EN|DATA, BASEPORT);
			outb(WRT_EN|DATA|CLK_ON  , BASEPORT);
			outb(WRT_EN|DATA, BASEPORT);
		}
		else
		{
			outb(WRT_EN|0x00, BASEPORT);
			outb(WRT_EN|0x00|CLK_ON  , BASEPORT);
		}
	}
	outb(0x00, BASEPORT);     
	
	spin_unlock(&lock);
  
  	return 0;
}

int tt_getsigstr(struct tt_device *dev)		/* TODO */
{
	if (inb(io) & 2)	/* bit set = no signal present	*/
		return 0;
	return 1;		/* signal present		*/
}


/* implement the video4linux api */

static int tt_ioctl(struct video_device *dev, unsigned int cmd, void *arg)
{
	struct tt_device *tt=dev->priv;
	
	switch(cmd)
	{
		case VIDIOCGCAP:
		{
			struct video_capability v;
			v.type=VID_TYPE_TUNER;
			v.channels=1;
			v.audios=1;
			/* No we don't do pictures */
			v.maxwidth=0;
			v.maxheight=0;
			v.minwidth=0;
			v.minheight=0;
			strcpy(v.name, "ActiveRadio");
			if(copy_to_user(arg,&v,sizeof(v)))
				return -EFAULT;
			return 0;
		}
		case VIDIOCGTUNER:
		{
			struct video_tuner v;
			if(copy_from_user(&v, arg,sizeof(v))!=0) 
				return -EFAULT;
			if(v.tuner)	/* Only 1 tuner */ 
				return -EINVAL;
			v.rangelow=(87*16000);
			v.rangehigh=(108*16000);
			v.flags=VIDEO_TUNER_LOW;
			v.mode=VIDEO_MODE_AUTO;
			strcpy(v.name, "FM");
			v.signal=0xFFFF*tt_getsigstr(tt);
			if(copy_to_user(arg,&v, sizeof(v)))
				return -EFAULT;
			return 0;
		}
		case VIDIOCSTUNER:
		{
			struct video_tuner v;
			if(copy_from_user(&v, arg, sizeof(v)))
				return -EFAULT;
			if(v.tuner!=0)
				return -EINVAL;
			/* Only 1 tuner so no setting needed ! */
			return 0;
		}
		case VIDIOCGFREQ:
			if(copy_to_user(arg, &tt->curfreq, sizeof(tt->curfreq)))
				return -EFAULT;
			return 0;
		case VIDIOCSFREQ:
			if(copy_from_user(&tt->curfreq, arg,sizeof(tt->curfreq)))
				return -EFAULT;
			tt_setfreq(tt, tt->curfreq);
			return 0;
		case VIDIOCGAUDIO:
		{	
			struct video_audio v;
			memset(&v,0, sizeof(v));
			v.flags|=VIDEO_AUDIO_MUTABLE|VIDEO_AUDIO_VOLUME;
			v.volume=tt->curvol * 6554;
			v.step=6554;
			strcpy(v.name, "Radio");
			if(copy_to_user(arg,&v, sizeof(v)))
				return -EFAULT;
			return 0;			
		}
		case VIDIOCSAUDIO:
		{
			struct video_audio v;
			if(copy_from_user(&v, arg, sizeof(v))) 
				return -EFAULT;	
			if(v.audio) 
				return -EINVAL;

			if(v.flags&VIDEO_AUDIO_MUTE) 
				tt_mute(tt);
			else
				tt_setvol(tt,v.volume/6554);	

			return 0;
		}
		default:
			return -ENOIOCTLCMD;
	}
}

static int tt_open(struct video_device *dev, int flags)
{
	if(users)
		return -EBUSY;
	users++;
	MOD_INC_USE_COUNT;
	return 0;
}

static void tt_close(struct video_device *dev)
{
	users--;
	MOD_DEC_USE_COUNT;
}

static struct tt_device terratec_unit;

static struct video_device terratec_radio=
{
	name:		"TerraTec ActiveRadio",
	type:		VID_TYPE_TUNER,
	hardware:	VID_HARDWARE_TERRATEC,
	open:		tt_open,
	close:		tt_close,
	ioctl:		tt_ioctl,
};

static int __init terratec_init(void)
{
	if(io==-1)
	{
		printk(KERN_ERR "You must set an I/O address with io=0x???\n");
		return -EINVAL;
	}
	if (!request_region(io, 2, "terratec")) 
	{
		printk(KERN_ERR "TerraTec: port 0x%x already in use\n", io);
		return -EBUSY;
	}

	terratec_radio.priv=&terratec_unit;
	
	spin_lock_init(&lock);
	
	if(video_register_device(&terratec_radio, VFL_TYPE_RADIO)==-1)
	{
		release_region(io,2);
		return -EINVAL;
	}
		
	printk(KERN_INFO "TERRATEC ActivRadio Standalone card driver.\n");

 	/* mute card - prevents noisy bootups */

	/* this ensures that the volume is all the way down  */
	cardWriteVol(0);
	terratec_unit.curvol = 0;

	return 0;
}

MODULE_AUTHOR("R.OFFERMANNS & others");
MODULE_DESCRIPTION("A driver for the TerraTec ActiveRadio Standalone radio card.");
MODULE_PARM(io, "i");
MODULE_PARM_DESC(io, "I/O address of the TerraTec ActiveRadio card (0x590 or 0x591)");

EXPORT_NO_SYMBOLS;

static void __exit terratec_cleanup_module(void)
{
	video_unregister_device(&terratec_radio);
	release_region(io,2);
	printk(KERN_INFO "TERRATEC ActivRadio Standalone card driver unloaded.\n");	
}

module_init(terratec_init);
module_exit(terratec_cleanup_module);