saa5249.c

powerpc内核mpc8241linux系统下char驱动程序

/*
 *	Cleaned up to use existing videodev interface and allow the idea
 *	of multiple teletext decoders on the video4linux iface. Changed i2c
 *	to cover addressing clashes on device busses. It's also rebuilt so
 *	you can add arbitary multiple teletext devices to Linux video4linux
 *	now (well 32 anyway).
 *
 *	Alan Cox <[e-mail]>
 *
 *	The original driver was heavily modified to match the i2c interface
 *	It was truncated to use the WinTV boards, too.
 *
 *	Copyright (c) 1998 Richard Guenther <[e-mail]>
 *
 * $Id: saa5249.c,v 1.1 1998/03/30 22:23:23 alan Exp $
 *
 *	Derived From
 *
 * vtx.c:
 * This is a loadable character-device-driver for videotext-interfaces
 * (aka teletext). Please check the Makefile/README for a list of supported
 * interfaces.
 *
 * Copyright (c) 1994-97 Martin Buck  <[e-mail]>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
 * USA.
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/malloc.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <stdarg.h>
#include <linux/i2c.h>
#include <linux/videotext.h>
#include <linux/videodev.h>

#define VTX_VER_MAJ 1
#define VTX_VER_MIN 7



#define NUM_DAUS 4
#define NUM_BUFS 8
#define IF_NAME "SAA5249"

static const int disp_modes[8][3] = 
{
	{ 0x46, 0x03, 0x03 },	/* DISPOFF */
	{ 0x46, 0xcc, 0xcc },	/* DISPNORM */
	{ 0x44, 0x0f, 0x0f },	/* DISPTRANS */
	{ 0x46, 0xcc, 0x46 },	/* DISPINS */
	{ 0x44, 0x03, 0x03 },	/* DISPOFF, interlaced */
	{ 0x44, 0xcc, 0xcc },	/* DISPNORM, interlaced */
	{ 0x44, 0x0f, 0x0f },	/* DISPTRANS, interlaced */
	{ 0x44, 0xcc, 0x46 }	/* DISPINS, interlaced */
};



#define PAGE_WAIT 30				/* Time in jiffies between requesting page and */
						/* checking status bits */
#define PGBUF_EXPIRE 1500			/* Time in jiffies to wait before retransmitting */
						/* page regardless of infobits */
typedef struct {
	u8 pgbuf[VTX_VIRTUALSIZE];		/* Page-buffer */
	u8 laststat[10];			/* Last value of infobits for DAU */
	u8 sregs[7];				/* Page-request registers */
	unsigned long expire;			/* Time when page will be expired */
	unsigned clrfound : 1;			/* VTXIOCCLRFOUND has been called */
	unsigned stopped : 1;			/* VTXIOCSTOPDAU has been called */
} vdau_t;

struct saa5249_device
{
	vdau_t vdau[NUM_DAUS];			/* Data for virtual DAUs (the 5249 only has one */
						/* real DAU, so we have to simulate some more) */
	int vtx_use_count;
	int is_searching[NUM_DAUS];
	int disp_mode;
	int virtual_mode;
	struct i2c_bus *bus;
};


#define CCTWR 34		/* I睠 write/read-address of vtx-chip */
#define CCTRD 35
#define NOACK_REPEAT 10		/* Retry access this many times on failure */
#define CLEAR_DELAY 5		/* Time in jiffies required to clear a page */
#define I2C_TIMEOUT 300		/* open/close/SDA-check timeout in jiffies */
#define READY_TIMEOUT 3		/* Time in jiffies to wait for ready signal of I睠-bus interface */
#define INIT_DELAY 500		/* Time in usec to wait at initialization of CEA interface */
#define START_DELAY 10		/* Time in usec to wait before starting write-cycle (CEA) */

#define VTX_DEV_MINOR 0

/* General defines and debugging support */

#ifndef FALSE
#define FALSE 0
#define TRUE 1
#endif
#ifndef MIN
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#endif

#define RESCHED \
        do { \
          if (current->need_resched) \
            schedule(); \
        } while (0)

static struct video_device saa_template;	/* Declared near bottom */

/*
 *	We do most of the hard work when we become a device on the i2c.
 */
 
static int saa5249_attach(struct i2c_device *device)
{
	int pgbuf;
	int err;
	struct video_device *vd;
	struct saa5249_device *t;
	/* Only attach these chips to the BT848 bus for now */
	
	if(device->bus->id!=I2C_BUSID_BT848)
		return -EINVAL;
	
	strcpy(device->name, IF_NAME);
	
	/*
	 *	Now create a video4linux device
	 */
	 
	vd=(struct video_device *)kmalloc(sizeof(struct video_device), GFP_KERNEL);
	if(vd==NULL)
		return -ENOMEM;
	
	memcpy(vd, &saa_template, sizeof(*vd));
	
	/*
	 *	Attach an saa5249 device
	 */
	
	t=(struct saa5249_device *)kmalloc(sizeof(struct saa5249_device), GFP_KERNEL);
	if(t==NULL)
	{
		kfree(vd);
		return -ENOMEM;
	}
	
	memset(t, 0, sizeof(*t));
	
	for (pgbuf = 0; pgbuf < NUM_DAUS; pgbuf++) 
	{
		memset(t->vdau[pgbuf].pgbuf, ' ', sizeof(t->vdau[0].pgbuf));
		memset(t->vdau[pgbuf].sregs, 0, sizeof(t->vdau[0].sregs));
		memset(t->vdau[pgbuf].laststat, 0, sizeof(t->vdau[0].laststat));
		t->vdau[pgbuf].expire = 0;
		t->vdau[pgbuf].clrfound = TRUE;
		t->vdau[pgbuf].stopped = TRUE;
		t->is_searching[pgbuf] = FALSE;
	}
	vd->priv=t;		 
	device->data=vd;
	
	/*
	 *	Register it
	 */

	if((err=video_register_device(vd, VFL_TYPE_VTX))<0)
	{
		kfree(t);
		kfree(vd);
		return err;
	}
	t->bus = device->bus;
	return 0;
}

static int saa5249_detach(struct i2c_device *device)
{
	struct video_device *vd=device->data;
	video_unregister_device(vd);
	kfree(vd->priv);
	kfree(vd);
	return 0;
}

static int saa5249_command(struct i2c_device *device,
			     unsigned int cmd, void *arg)
{
	return -EINVAL;
}

/* new I2C driver support */

static struct i2c_driver i2c_driver_videotext = 
{
	IF_NAME,		/* name */
	I2C_DRIVERID_VIDEOTEXT, /* in i2c.h */
	34, 35,			/* Addr range */
	saa5249_attach,
	saa5249_detach,
	saa5249_command
};

/*
 *	Wait the given number of jiffies (10ms). This calls the scheduler, so the actual
 *	delay may be longer.
 */

static void jdelay(unsigned long delay) 
{
	sigset_t oldblocked = current->blocked;

	spin_lock_irq(&current->sigmask_lock);
	sigfillset(&current->blocked);
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);
	current->state = TASK_INTERRUPTIBLE;
	schedule_timeout(delay);

	spin_lock_irq(&current->sigmask_lock);
	current->blocked = oldblocked;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);
}


/* Send arbitrary number of bytes to I睠-bus. Start & stop handshaking is done by this routine.
 * adr should be address of I睠-device, varargs-list of values to send must be terminated by -1
 * Returns -1 if I睠-device didn't send acknowledge, 0 otherwise
 */

static int i2c_senddata(struct saa5249_device *t, int adr, ...) 
{
	int val, loop;
	va_list argp;

	for (loop = 0; loop <= NOACK_REPEAT; loop++) 
	{
		i2c_start(t->bus);
		if (i2c_sendbyte(t->bus, adr, 0) != 0)
			goto loopend;

		va_start(argp, adr);
		while ((val = va_arg(argp, int)) != -1) 
		{
			if (val < 0 || val > 255) 
			{
				printk(KERN_ERR "vtx: internal error in i2c_senddata\n");
				break;
			}
			if (i2c_sendbyte(t->bus, val, 0) != 0)
				goto loopend;
		}
		va_end(argp);
		i2c_stop(t->bus);
		return 0;
loopend:
		i2c_stop(t->bus);
	}
	va_end(argp);
	return -1;
}


/* Send count number of bytes from buffer buf to I睠-device adr. Start & stop handshaking is
 * done by this routine. If uaccess is TRUE, data is read from user-space with get_user.
 * Returns -1 if I睠-device didn't send acknowledge, 0 otherwise
 */

static int i2c_sendbuf(struct saa5249_device *t, int adr, int reg, int count, u8 *buf, int uaccess) 
{
	int pos, loop;
	u8 val;

	for (loop = 0; loop <= NOACK_REPEAT; loop++) 
	{
		i2c_start(t->bus);
		if (i2c_sendbyte(t->bus, adr, 0) != 0 || i2c_sendbyte(t->bus, reg, 0) != 0)
			goto loopend;
		for (pos = 0; pos < count; pos++) 
		{
			/* FIXME: FAULT WITH CLI/SPINLOCK ?? */
			if (uaccess)
				get_user(val, buf + pos);
			else
				val = buf[pos];
			if (i2c_sendbyte(t->bus, val, 0) != 0)
				goto loopend;
			RESCHED;
		}
		i2c_stop(t->bus);
		return 0;
loopend:
		i2c_stop(t->bus);
	}
	return -1;
}


/* Get count number of bytes from I睠-device at address adr, store them in buf. Start & stop
 * handshaking is done by this routine, ack will be sent after the last byte to inhibit further
 * sending of data. If uaccess is TRUE, data is written to user-space with put_user.
 * Returns -1 if I睠-device didn't send acknowledge, 0 otherwise
 */

static int i2c_getdata(struct saa5249_device *t, int adr, int count, u8 *buf, int uaccess) 
{
	int pos, loop, val;

	for (loop = 0; loop <= NOACK_REPEAT; loop++) 
	{
		i2c_start(t->bus);
		if (i2c_sendbyte(t->bus, adr, 1) != 0)
			goto loopend;
		for (pos = 0; pos < count; pos++) 
		{
			val = i2c_readbyte(t->bus, (pos==count-1) ? 1 : 0);
			if (uaccess) 
				put_user(val, buf + pos);
			else
				buf[pos] = val;
			RESCHED;
		}
		i2c_stop(t->bus);
		return 0;
loopend:
		i2c_stop(t->bus);
	}
	return -1;
}