/*
 * Modified in order to keep it compatible both with new and old videotext IOCTLs by
 * Michael Geng <linux@MichaelGeng.de>
 *
 *      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 <Alan.Cox@linux.org>
 *
 *      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 <richard.guenther@student.uni-tuebingen.de>
 *
 *      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  <martin-2.buck@student.uni-ulm.de>
 *
 *
 * 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/mm.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/videotext.h>
#include <linux/videodev.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-i2c-drv-legacy.h>

MODULE_AUTHOR("Michael Geng <linux@MichaelGeng.de>");
MODULE_DESCRIPTION("Philips SAA5249 Teletext decoder driver");
MODULE_LICENSE("GPL");

#define VTX_VER_MAJ 1
#define VTX_VER_MIN 8


#define NUM_DAUS 4
#define NUM_BUFS 8

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    msecs_to_jiffies(300)      /* Time between requesting page and */
                                                /* checking status bits */
#define PGBUF_EXPIRE msecs_to_jiffies(15000)    /* Time 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_client *client;
        unsigned long in_use;
        struct mutex lock;
};


#define CCTWR 34                /* I²C write/read-address of vtx-chip */
#define CCTRD 35
#define NOACK_REPEAT 10         /* Retry access this many times on failure */
#define CLEAR_DELAY   msecs_to_jiffies(50)      /* Time required to clear a page */
#define READY_TIMEOUT msecs_to_jiffies(30)      /* Time to wait for ready signal of I2C-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

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

/*
 *      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->sighand->siglock);
        sigfillset(&current->blocked);
        recalc_sigpending();
        spin_unlock_irq(&current->sighand->siglock);
        msleep_interruptible(jiffies_to_msecs(delay));

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


/*
 *      I2C interfaces
 */

static int i2c_sendbuf(struct saa5249_device *t, int reg, int count, u8 *data)
{
        char buf[64];

        buf[0] = reg;
        memcpy(buf+1, data, count);

        if (i2c_master_send(t->client, buf, count + 1) == count + 1)
                return 0;
        return -1;
}

static int i2c_senddata(struct saa5249_device *t, ...)
{
        unsigned char buf[64];
        int v;
        int ct = 0;
        va_list argp;
        va_start(argp,t);

        while ((v = va_arg(argp, int)) != -1)
                buf[ct++] = v;

        va_end(argp);
        return i2c_sendbuf(t, buf[0], ct-1, buf+1);
}

/* Get count number of bytes from I²C-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 I²C-device didn't send acknowledge, 0 otherwise
 */

static int i2c_getdata(struct saa5249_device *t, int count, u8 *buf)
{
        if(i2c_master_recv(t->client, buf, count)!=count)
                return -1;
        return 0;
}


/*
 *      Standard character-device-driver functions
 */

static int do_saa5249_ioctl(struct inode *inode, struct file *file,
                            unsigned int cmd, void *arg)
{
        static int virtual_mode = false;
        struct saa5249_device *t = video_drvdata(file);

        switch (cmd) {
        case VTXIOCGETINFO:
        {
                vtx_info_t *info = arg;
                info->version_major = VTX_VER_MAJ;
                info->version_minor = VTX_VER_MIN;
                info->numpages = NUM_DAUS;
                /*info->cct_type = CCT_TYPE;*/
                return 0;
        }

        case VTXIOCCLRPAGE:
        {
                vtx_pagereq_t *req = arg;

                if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
                        return -EINVAL;
                memset(t->vdau[req->pgbuf].pgbuf, ' ', sizeof(t->vdau[0].pgbuf));
                t->vdau[req->pgbuf].clrfound = true;
                return 0;
        }

        case VTXIOCCLRFOUND:
        {
                vtx_pagereq_t *req = arg;

                if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
                        return -EINVAL;
                t->vdau[req->pgbuf].clrfound = true;
                return 0;
        }

        case VTXIOCPAGEREQ:
        {
                vtx_pagereq_t *req = arg;
                if (!(req->pagemask & PGMASK_PAGE))
                        req->page = 0;
                if (!(req->pagemask & PGMASK_HOUR))
                        req->hour = 0;
                if (!(req->pagemask & PGMASK_MINUTE))
                        req->minute = 0;
                if (req->page < 0 || req->page > 0x8ff) /* 7FF ?? */
                        return -EINVAL;
                req->page &= 0x7ff;
                if (req->hour < 0 || req->hour > 0x3f || req->minute < 0 || req->minute > 0x7f ||
                        req->pagemask < 0 || req->pagemask >= PGMASK_MAX || req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
                        return -EINVAL;
                t->vdau[req->pgbuf].sregs[0] = (req->pagemask & PG_HUND ? 0x10 : 0) | (req->page / 0x100);
                t->vdau[req->pgbuf].sregs[1] = (req->pagemask & PG_TEN ? 0x10 : 0) | ((req->page / 0x10) & 0xf);
                t->vdau[req->pgbuf].sregs[2] = (req->pagemask & PG_UNIT ? 0x10 : 0) | (req->page & 0xf);
                t->vdau[req->pgbuf].sregs[3] = (req->pagemask & HR_TEN ? 0x10 : 0) | (req->hour / 0x10);
                t->vdau[req->pgbuf].sregs[4] = (req->pagemask & HR_UNIT ? 0x10 : 0) | (req->hour & 0xf);
                t->vdau[req->pgbuf].sregs[5] = (req->pagemask & MIN_TEN ? 0x10 : 0) | (req->minute / 0x10);
                t->vdau[req->pgbuf].sregs[6] = (req->pagemask & MIN_UNIT ? 0x10 : 0) | (req->minute & 0xf);
                t->vdau[req->pgbuf].stopped = false;
                t->vdau[req->pgbuf].clrfound = true;
                t->is_searching[req->pgbuf] = true;
                return 0;
        }

        case VTXIOCGETSTAT:
        {
                vtx_pagereq_t *req = arg;
                u8 infobits[10];
                vtx_pageinfo_t info;
                int a;

                if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
                        return -EINVAL;
                if (!t->vdau[req->pgbuf].stopped) {
                        if (i2c_senddata(t, 2, 0, -1) ||
                                i2c_sendbuf(t, 3, sizeof(t->vdau[0].sregs), t->vdau[req->pgbuf].sregs) ||
                                i2c_senddata(t, 8, 0, 25, 0, ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', -1) ||
                                i2c_senddata(t, 2, 0, t->vdau[req->pgbuf].sregs[0] | 8, -1) ||
                                i2c_senddata(t, 8, 0, 25, 0, -1))
                                return -EIO;
                        jdelay(PAGE_WAIT);
                        if (i2c_getdata(t, 10, infobits))
                                return -EIO;

                        if (!(infobits[8] & 0x10) && !(infobits[7] & 0xf0) &&   /* check FOUND-bit */
                                (memcmp(infobits, t->vdau[req->pgbuf].laststat, sizeof(infobits)) ||
                                time_after_eq(jiffies, t->vdau[req->pgbuf].expire)))
                        {               /* check if new page arrived */
                                if (i2c_senddata(t, 8, 0, 0, 0, -1) ||
                                        i2c_getdata(t, VTX_PAGESIZE, t->vdau[req->pgbuf].pgbuf))
                                        return -EIO;
                                t->vdau[req->pgbuf].expire = jiffies + PGBUF_EXPIRE;
                                memset(t->vdau[req->pgbuf].pgbuf + VTX_PAGESIZE, ' ', VTX_VIRTUALSIZE - VTX_PAGESIZE);
                                if (t->virtual_mode) {
                                        /* Packet X/24 */
                                        if (i2c_senddata(t, 8, 0, 0x20, 0, -1) ||
                                                i2c_getdata(t, 40, t->vdau[req->pgbuf].pgbuf + VTX_PAGESIZE + 20 * 40))
                                                return -EIO;
                                        /* Packet X/27/0 */
                                        if (i2c_senddata(t, 8, 0, 0x21, 0, -1) ||
                                                i2c_getdata(t, 40, t->vdau[req->pgbuf].pgbuf + VTX_PAGESIZE + 16 * 40))
                                                return -EIO;
                                        /* Packet 8/30/0...8/30/15
                                         * FIXME: AFAIK, the 5249 does hamming-decoding for some bytes in packet 8/30,
                                         *        so we should undo this here.
                                         */
                                        if (i2c_senddata(t, 8, 0, 0x22, 0, -1) ||
                                                i2c_getdata(t, 40, t->vdau[req->pgbuf].pgbuf + VTX_PAGESIZE + 23 * 40))
                                                return -EIO;
                                }
                                t->vdau[req->pgbuf].clrfound = false;
                                memcpy(t->vdau[req->pgbuf].laststat, infobits, sizeof(infobits));
                        } else {
                                memcpy(infobits, t->vdau[req->pgbuf].laststat, sizeof(infobits));
                        }
                } else {
                        memcpy(infobits, t->vdau[req->pgbuf].laststat, sizeof(infobits));
                }

                info.pagenum = ((infobits[8] << 8) & 0x700) | ((infobits[1] << 4) & 0xf0) | (infobits[0] & 0x0f);
                if (info.pagenum < 0x100)
                        info.pagenum += 0x800;
                info.hour = ((infobits[5] << 4) & 0x30) | (infobits[4] & 0x0f);
                info.minute = ((infobits[3] << 4) & 0x70) | (infobits[2] & 0x0f);
                info.charset = ((infobits[7] >> 1) & 7);
                info.delete = !!(infobits[3] & 8);
                info.headline = !!(infobits[5] & 4);
                info.subtitle = !!(infobits[5] & 8);
                info.supp_header = !!(infobits[6] & 1);
                info.update = !!(infobits[6] & 2);
                info.inter_seq = !!(infobits[6] & 4);
                info.dis_disp = !!(infobits[6] & 8);
                info.serial = !!(infobits[7] & 1);
                info.notfound = !!(infobits[8] & 0x10);
                info.pblf = !!(infobits[9] & 0x20);
                info.hamming = 0;
                for (a = 0; a <= 7; a++) {
                        if (infobits[a] & 0xf0) {
                                info.hamming = 1;
                                break;
                        }
                }
                if (t->vdau[req->pgbuf].clrfound)
                        info.notfound = 1;
                if (copy_to_user(req->buffer, &info, sizeof(vtx_pageinfo_t)))
                        return -EFAULT;
                if (!info.hamming && !info.notfound)
                        t->is_searching[req->pgbuf] = false;
                return 0;
        }

        case VTXIOCGETPAGE:
        {
                vtx_pagereq_t *req = arg;
                int start, end;

                if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS || req->start < 0 ||
                        req->start > req->end || req->end >= (virtual_mode ? VTX_VIRTUALSIZE : VTX_PAGESIZE))
                        return -EINVAL;
                if (copy_to_user(req->buffer, &t->vdau[req->pgbuf].pgbuf[req->start], req->end - req->start + 1))
                        return -EFAULT;

                 /*
                  *     Always read the time directly from SAA5249
                  */

                if (req->start <= 39 && req->end >= 32) {
                        int len;
                        char buf[16];
                        start = max(req->start, 32);
                        end = min(req->end, 39);
                        len = end - start + 1;
                        if (i2c_senddata(t, 8, 0, 0, start, -1) ||
                                i2c_getdata(t, len, buf))
                                return -EIO;
                        if (copy_to_user(req->buffer + start - req->start, buf, len))
                                return -EFAULT;
                }
                /* Insert the current header if DAU is still searching for a page */
                if (req->start <= 31 && req->end >= 7 && t->is_searching[req->pgbuf]) {
                        char buf[32];
                        int len;

                        start = max(req->start, 7);
                        end = min(req->end, 31);
                        len = end - start + 1;
                        if (i2c_senddata(t, 8, 0, 0, start, -1) ||
                                i2c_getdata(t, len, buf))
                                return -EIO;
                        if (copy_to_user(req->buffer + start - req->start, buf, len))
                                return -EFAULT;
                }
                return 0;
        }

        case VTXIOCSTOPDAU:
        {
                vtx_pagereq_t *req = arg;

                if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
                        return -EINVAL;
                t->vdau[req->pgbuf].stopped = true;
                t->is_searching[req->pgbuf] = false;
                return 0;
        }

        case VTXIOCPUTPAGE:
        case VTXIOCSETDISP:
        case VTXIOCPUTSTAT:
                return 0;

        case VTXIOCCLRCACHE:
        {
                if (i2c_senddata(t, 0, NUM_DAUS, 0, 8, -1) || i2c_senddata(t, 11,
                        ' ', ' ', ' ', ' ', ' ', ' ',
                        ' ', ' ', ' ', ' ', ' ', ' ',
                        ' ', ' ', ' ', ' ', ' ', ' ',
                        ' ', ' ', ' ', ' ', ' ', ' ',
                        -1))
                        return -EIO;
                if (i2c_senddata(t, 3, 0x20, -1))
                        return -EIO;
                jdelay(10 * CLEAR_DELAY);                       /* I have no idea how long we have to wait here */
                return 0;
        }

        case VTXIOCSETVIRT:
        {
                /* The SAA5249 has virtual-row reception turned on always */
                t->virtual_mode = (int)(long)arg;
                return 0;
        }
        }
        return -EINVAL;
}

/*
 * Translates old vtx IOCTLs to new ones
 *
 * This keeps new kernel versions compatible with old userspace programs.
 */
static inline unsigned int vtx_fix_command(unsigned int cmd)
{
        switch (cmd) {
        case VTXIOCGETINFO_OLD:
                cmd = VTXIOCGETINFO;
                break;
        case VTXIOCCLRPAGE_OLD:
                cmd = VTXIOCCLRPAGE;
                break;
        case VTXIOCCLRFOUND_OLD:
                cmd = VTXIOCCLRFOUND;
                break;
        case VTXIOCPAGEREQ_OLD:
                cmd = VTXIOCPAGEREQ;
                break;
        case VTXIOCGETSTAT_OLD:
                cmd = VTXIOCGETSTAT;
                break;
        case VTXIOCGETPAGE_OLD:
                cmd = VTXIOCGETPAGE;
                break;
        case VTXIOCSTOPDAU_OLD:
                cmd = VTXIOCSTOPDAU;
                break;
        case VTXIOCPUTPAGE_OLD:
                cmd = VTXIOCPUTPAGE;
                break;
        case VTXIOCSETDISP_OLD:
                cmd = VTXIOCSETDISP;
                break;
        case VTXIOCPUTSTAT_OLD:
                cmd = VTXIOCPUTSTAT;
                break;
        case VTXIOCCLRCACHE_OLD:
                cmd = VTXIOCCLRCACHE;
                break;
        case VTXIOCSETVIRT_OLD:
                cmd = VTXIOCSETVIRT;
                break;
        }
        return cmd;
}

/*
 *      Handle the locking
 */

static int saa5249_ioctl(struct inode *inode, struct file *file,
                         unsigned int cmd, unsigned long arg)
{
        struct saa5249_device *t = video_drvdata(file);
        int err;

        cmd = vtx_fix_command(cmd);
        mutex_lock(&t->lock);
        err = video_usercopy(inode,file,cmd,arg,do_saa5249_ioctl);
        mutex_unlock(&t->lock);
        return err;
}

static int saa5249_open(struct inode *inode, struct file *file)
{
        struct saa5249_device *t = video_drvdata(file);
        int pgbuf;

        if (t->client == NULL)
                return -ENODEV;

        if (test_and_set_bit(0, &t->in_use))
                return -EBUSY;

        if (i2c_senddata(t, 0, 0, -1) || /* Select R11 */
                /* Turn off parity checks (we do this ourselves) */
                i2c_senddata(t, 1, disp_modes[t->disp_mode][0], 0, -1) ||
                /* Display TV-picture, no virtual rows */
                i2c_senddata(t, 4, NUM_DAUS, disp_modes[t->disp_mode][1], disp_modes[t->disp_mode][2], 7, -1))
                /* Set display to page 4 */
        {
                clear_bit(0, &t->in_use);
                return -EIO;
        }

        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;
        }
        t->virtual_mode = false;
        return 0;
}



static int saa5249_release(struct inode *inode, struct file *file)
{
        struct saa5249_device *t = video_drvdata(file);

        i2c_senddata(t, 1, 0x20, -1);           /* Turn off CCT */
        i2c_senddata(t, 5, 3, 3, -1);           /* Turn off TV-display */
        clear_bit(0, &t->in_use);
        return 0;
}

static const struct file_operations saa_fops = {
        .owner          = THIS_MODULE,
        .open           = saa5249_open,
        .release        = saa5249_release,
        .ioctl          = saa5249_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = v4l_compat_ioctl32,
#endif
        .llseek         = no_llseek,
};

static struct video_device saa_template =
{
        .name           = "saa5249",
        .fops           = &saa_fops,
        .release        = video_device_release,
};

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x22 >> 1, I2C_CLIENT_END };

I2C_CLIENT_INSMOD;

static int saa5249_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        int pgbuf;
        int err;
        struct video_device *vd;
        struct saa5249_device *t;

        v4l_info(client, "chip found @ 0x%x (%s)\n",
                        client->addr << 1, client->adapter->name);
        v4l_info(client, "VideoText version %d.%d\n",
                        VTX_VER_MAJ, VTX_VER_MIN);
        t = kzalloc(sizeof(*t), GFP_KERNEL);
        if (t == NULL)
                return -ENOMEM;
        mutex_init(&t->lock);

        /* Now create a video4linux device */
        vd = kmalloc(sizeof(struct video_device), GFP_KERNEL);
        if (vd == NULL) {
                kfree(client);
                return -ENOMEM;
        }
        i2c_set_clientdata(client, vd);
        memcpy(vd, &saa_template, sizeof(*vd));

        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;
        }
        video_set_drvdata(vd, t);

        /* Register it */
        err = video_register_device(vd, VFL_TYPE_VTX, -1);
        if (err < 0) {
                kfree(t);
                kfree(vd);
                return err;
        }
        t->client = client;
        return 0;
}

static int saa5249_remove(struct i2c_client *client)
{
        struct video_device *vd = i2c_get_clientdata(client);

        video_unregister_device(vd);
        kfree(video_get_drvdata(vd));
        kfree(vd);
        return 0;
}

static const struct i2c_device_id saa5249_id[] = {
        { "saa5249", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, saa5249_id);

static struct v4l2_i2c_driver_data v4l2_i2c_data = {
        .name = "saa5249",
        .driverid = I2C_DRIVERID_SAA5249,
        .probe = saa5249_probe,
        .remove = saa5249_remove,
        .id_table = saa5249_id,
};