/*
   em28xx-i2c.c - driver for Empia EM2800/EM2820/2840 USB video capture devices

   Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
                      Markus Rechberger <mrechberger@gmail.com>
                      Mauro Carvalho Chehab <mchehab@infradead.org>
                      Sascha Sommer <saschasommer@freenet.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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/usb.h>
#include <linux/i2c.h>

#include "em28xx.h"
#include "tuner-xc2028.h"
#include <media/v4l2-common.h>
#include <media/tuner.h>

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

static unsigned int i2c_scan;
module_param(i2c_scan, int, 0444);
MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");

static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");


#define dprintk1(lvl, fmt, args...)                     \
do {                                                    \
        if (i2c_debug >= lvl) {                         \
        printk(fmt, ##args);                            \
      }                                                 \
} while (0)

#define dprintk2(lvl, fmt, args...)                     \
do {                                                    \
        if (i2c_debug >= lvl) {                         \
                printk(KERN_DEBUG "%s at %s: " fmt,     \
                       dev->name, __func__ , ##args);   \
      }                                                 \
} while (0)

/*
 * em2800_i2c_send_max4()
 * send up to 4 bytes to the i2c device
 */
static int em2800_i2c_send_max4(struct em28xx *dev, unsigned char addr,
                                char *buf, int len)
{
        int ret;
        int write_timeout;
        unsigned char b2[6];
        BUG_ON(len < 1 || len > 4);
        b2[5] = 0x80 + len - 1;
        b2[4] = addr;
        b2[3] = buf[0];
        if (len > 1)
                b2[2] = buf[1];
        if (len > 2)
                b2[1] = buf[2];
        if (len > 3)
                b2[0] = buf[3];

        ret = dev->em28xx_write_regs(dev, 4 - len, &b2[4 - len], 2 + len);
        if (ret != 2 + len) {
                em28xx_warn("writing to i2c device failed (error=%i)\n", ret);
                return -EIO;
        }
        for (write_timeout = EM2800_I2C_WRITE_TIMEOUT; write_timeout > 0;
             write_timeout -= 5) {
                ret = dev->em28xx_read_reg(dev, 0x05);
                if (ret == 0x80 + len - 1)
                        return len;
                msleep(5);
        }
        em28xx_warn("i2c write timed out\n");
        return -EIO;
}

/*
 * em2800_i2c_send_bytes()
 */
static int em2800_i2c_send_bytes(void *data, unsigned char addr, char *buf,
                                 short len)
{
        char *bufPtr = buf;
        int ret;
        int wrcount = 0;
        int count;
        int maxLen = 4;
        struct em28xx *dev = (struct em28xx *)data;
        while (len > 0) {
                count = (len > maxLen) ? maxLen : len;
                ret = em2800_i2c_send_max4(dev, addr, bufPtr, count);
                if (ret > 0) {
                        len -= count;
                        bufPtr += count;
                        wrcount += count;
                } else
                        return (ret < 0) ? ret : -EFAULT;
        }
        return wrcount;
}

/*
 * em2800_i2c_check_for_device()
 * check if there is a i2c_device at the supplied address
 */
static int em2800_i2c_check_for_device(struct em28xx *dev, unsigned char addr)
{
        char msg;
        int ret;
        int write_timeout;
        msg = addr;
        ret = dev->em28xx_write_regs(dev, 0x04, &msg, 1);
        if (ret < 0) {
                em28xx_warn("setting i2c device address failed (error=%i)\n",
                            ret);
                return ret;
        }
        msg = 0x84;
        ret = dev->em28xx_write_regs(dev, 0x05, &msg, 1);
        if (ret < 0) {
                em28xx_warn("preparing i2c read failed (error=%i)\n", ret);
                return ret;
        }
        for (write_timeout = EM2800_I2C_WRITE_TIMEOUT; write_timeout > 0;
             write_timeout -= 5) {
                unsigned reg = dev->em28xx_read_reg(dev, 0x5);

                if (reg == 0x94)
                        return -ENODEV;
                else if (reg == 0x84)
                        return 0;
                msleep(5);
        }
        return -ENODEV;
}

/*
 * em2800_i2c_recv_bytes()
 * read from the i2c device
 */
static int em2800_i2c_recv_bytes(struct em28xx *dev, unsigned char addr,
                                 char *buf, int len)
{
        int ret;
        /* check for the device and set i2c read address */
        ret = em2800_i2c_check_for_device(dev, addr);
        if (ret) {
                em28xx_warn
                    ("preparing read at i2c address 0x%x failed (error=%i)\n",
                     addr, ret);
                return ret;
        }
        ret = dev->em28xx_read_reg_req_len(dev, 0x0, 0x3, buf, len);
        if (ret < 0) {
                em28xx_warn("reading from i2c device at 0x%x failed (error=%i)",
                            addr, ret);
                return ret;
        }
        return ret;
}

/*
 * em28xx_i2c_send_bytes()
 * untested for more than 4 bytes
 */
static int em28xx_i2c_send_bytes(void *data, unsigned char addr, char *buf,
                                 short len, int stop)
{
        int wrcount = 0;
        struct em28xx *dev = (struct em28xx *)data;

        wrcount = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len);

        return wrcount;
}

/*
 * em28xx_i2c_recv_bytes()
 * read a byte from the i2c device
 */
static int em28xx_i2c_recv_bytes(struct em28xx *dev, unsigned char addr,
                                 char *buf, int len)
{
        int ret;
        ret = dev->em28xx_read_reg_req_len(dev, 2, addr, buf, len);
        if (ret < 0) {
                em28xx_warn("reading i2c device failed (error=%i)\n", ret);
                return ret;
        }
        if (dev->em28xx_read_reg(dev, 0x5) != 0)
                return -ENODEV;
        return ret;
}

/*
 * em28xx_i2c_check_for_device()
 * check if there is a i2c_device at the supplied address
 */
static int em28xx_i2c_check_for_device(struct em28xx *dev, unsigned char addr)
{
        char msg;
        int ret;
        msg = addr;

        ret = dev->em28xx_read_reg_req(dev, 2, addr);
        if (ret < 0) {
                em28xx_warn("reading from i2c device failed (error=%i)\n", ret);
                return ret;
        }
        if (dev->em28xx_read_reg(dev, 0x5) != 0)
                return -ENODEV;
        return 0;
}

/*
 * em28xx_i2c_xfer()
 * the main i2c transfer function
 */
static int em28xx_i2c_xfer(struct i2c_adapter *i2c_adap,
                           struct i2c_msg msgs[], int num)
{
        struct em28xx *dev = i2c_adap->algo_data;
        int addr, rc, i, byte;

        if (num <= 0)
                return 0;
        for (i = 0; i < num; i++) {
                addr = msgs[i].addr << 1;
                dprintk2(2, "%s %s addr=%x len=%d:",
                         (msgs[i].flags & I2C_M_RD) ? "read" : "write",
                         i == num - 1 ? "stop" : "nonstop", addr, msgs[i].len);
                if (!msgs[i].len) { /* no len: check only for device presence */
                        if (dev->board.is_em2800)
                                rc = em2800_i2c_check_for_device(dev, addr);
                        else
                                rc = em28xx_i2c_check_for_device(dev, addr);
                        if (rc < 0) {
                                dprintk2(2, " no device\n");
                                return rc;
                        }

                } else if (msgs[i].flags & I2C_M_RD) {
                        /* read bytes */
                        if (dev->board.is_em2800)
                                rc = em2800_i2c_recv_bytes(dev, addr,
                                                           msgs[i].buf,
                                                           msgs[i].len);
                        else
                                rc = em28xx_i2c_recv_bytes(dev, addr,
                                                           msgs[i].buf,
                                                           msgs[i].len);
                        if (i2c_debug >= 2) {
                                for (byte = 0; byte < msgs[i].len; byte++)
                                        printk(" %02x", msgs[i].buf[byte]);
                        }
                } else {
                        /* write bytes */
                        if (i2c_debug >= 2) {
                                for (byte = 0; byte < msgs[i].len; byte++)
                                        printk(" %02x", msgs[i].buf[byte]);
                        }
                        if (dev->board.is_em2800)
                                rc = em2800_i2c_send_bytes(dev, addr,
                                                           msgs[i].buf,
                                                           msgs[i].len);
                        else
                                rc = em28xx_i2c_send_bytes(dev, addr,
                                                           msgs[i].buf,
                                                           msgs[i].len,
                                                           i == num - 1);
                }
                if (rc < 0)
                        goto err;
                if (i2c_debug >= 2)
                        printk("\n");
        }

        return num;
err:
        dprintk2(2, " ERROR: %i\n", rc);
        return rc;
}

/* based on linux/sunrpc/svcauth.h and linux/hash.h
 * The original hash function returns a different value, if arch is x86_64
 *  or i386.
 */
static inline unsigned long em28xx_hash_mem(char *buf, int length, int bits)
{
        unsigned long hash = 0;
        unsigned long l = 0;
        int len = 0;
        unsigned char c;
        do {
                if (len == length) {
                        c = (char)len;
                        len = -1;
                } else
                        c = *buf++;
                l = (l << 8) | c;
                len++;
                if ((len & (32 / 8 - 1)) == 0)
                        hash = ((hash^l) * 0x9e370001UL);
        } while (len);

        return (hash >> (32 - bits)) & 0xffffffffUL;
}

static int em28xx_i2c_eeprom(struct em28xx *dev, unsigned char *eedata, int len)
{
        unsigned char buf, *p = eedata;
        struct em28xx_eeprom *em_eeprom = (void *)eedata;
        int i, err, size = len, block;

        if (dev->chip_id == CHIP_ID_EM2874) {
                /* Empia switched to a 16-bit addressable eeprom in newer
                   devices.  While we could certainly write a routine to read
                   the eeprom, there is nothing of use in there that cannot be
                   accessed through registers, and there is the risk that we
                   could corrupt the eeprom (since a 16-bit read call is
                   interpreted as a write call by 8-bit eeproms).
                */
                return 0;
        }

        dev->i2c_client.addr = 0xa0 >> 1;

        /* Check if board has eeprom */
        err = i2c_master_recv(&dev->i2c_client, &buf, 0);
        if (err < 0) {
                em28xx_errdev("board has no eeprom\n");
                memset(eedata, 0, len);
                return -ENODEV;
        }

        buf = 0;

        err = i2c_master_send(&dev->i2c_client, &buf, 1);
        if (err != 1) {
                printk(KERN_INFO "%s: Huh, no eeprom present (err=%d)?\n",
                       dev->name, err);
                return err;
        }
        while (size > 0) {
                if (size > 16)
                        block = 16;
                else
                        block = size;

                if (block !=
                    (err = i2c_master_recv(&dev->i2c_client, p, block))) {
                        printk(KERN_WARNING
                               "%s: i2c eeprom read error (err=%d)\n",
                               dev->name, err);
                        return err;
                }
                size -= block;
                p += block;
        }
        for (i = 0; i < len; i++) {
                if (0 == (i % 16))
                        printk(KERN_INFO "%s: i2c eeprom %02x:", dev->name, i);
                printk(" %02x", eedata[i]);
                if (15 == (i % 16))
                        printk("\n");
        }

        if (em_eeprom->id == 0x9567eb1a)
                dev->hash = em28xx_hash_mem(eedata, len, 32);

        printk(KERN_INFO "%s: EEPROM ID= 0x%08x, EEPROM hash = 0x%08lx\n",
               dev->name, em_eeprom->id, dev->hash);

        printk(KERN_INFO "%s: EEPROM info:\n", dev->name);

        switch (em_eeprom->chip_conf >> 4 & 0x3) {
        case 0:
                printk(KERN_INFO "%s:\tNo audio on board.\n", dev->name);
                break;
        case 1:
                printk(KERN_INFO "%s:\tAC97 audio (5 sample rates)\n",
                                 dev->name);
                break;
        case 2:
                printk(KERN_INFO "%s:\tI2S audio, sample rate=32k\n",
                                 dev->name);
                break;
        case 3:
                printk(KERN_INFO "%s:\tI2S audio, 3 sample rates\n",
                                 dev->name);
                break;
        }

        if (em_eeprom->chip_conf & 1 << 3)
                printk(KERN_INFO "%s:\tUSB Remote wakeup capable\n", dev->name);

        if (em_eeprom->chip_conf & 1 << 2)
                printk(KERN_INFO "%s:\tUSB Self power capable\n", dev->name);

        switch (em_eeprom->chip_conf & 0x3) {
        case 0:
                printk(KERN_INFO "%s:\t500mA max power\n", dev->name);
                break;
        case 1:
                printk(KERN_INFO "%s:\t400mA max power\n", dev->name);
                break;
        case 2:
                printk(KERN_INFO "%s:\t300mA max power\n", dev->name);
                break;
        case 3:
                printk(KERN_INFO "%s:\t200mA max power\n", dev->name);
                break;
        }
        printk(KERN_INFO "%s:\tTable at 0x%02x, strings=0x%04x, 0x%04x, 0x%04x\n",
                                dev->name,
                                em_eeprom->string_idx_table,
                                em_eeprom->string1,
                                em_eeprom->string2,
                                em_eeprom->string3);

        return 0;
}

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

/*
 * functionality()
 */
static u32 functionality(struct i2c_adapter *adap)
{
        return I2C_FUNC_SMBUS_EMUL;
}

static struct i2c_algorithm em28xx_algo = {
        .master_xfer   = em28xx_i2c_xfer,
        .functionality = functionality,
};

static struct i2c_adapter em28xx_adap_template = {
        .owner = THIS_MODULE,
        .name = "em28xx",
        .algo = &em28xx_algo,
};

static struct i2c_client em28xx_client_template = {
        .name = "em28xx internal",
};

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

/*
 * i2c_devs
 * incomplete list of known devices
 */
static char *i2c_devs[128] = {
        [0x4a >> 1] = "saa7113h",
        [0x60 >> 1] = "remote IR sensor",
        [0x8e >> 1] = "remote IR sensor",
        [0x86 >> 1] = "tda9887",
        [0x80 >> 1] = "msp34xx",
        [0x88 >> 1] = "msp34xx",
        [0xa0 >> 1] = "eeprom",
        [0xb0 >> 1] = "tda9874",
        [0xb8 >> 1] = "tvp5150a",
        [0xba >> 1] = "webcam sensor or tvp5150a",
        [0xc0 >> 1] = "tuner (analog)",
        [0xc2 >> 1] = "tuner (analog)",
        [0xc4 >> 1] = "tuner (analog)",
        [0xc6 >> 1] = "tuner (analog)",
};

/*
 * do_i2c_scan()
 * check i2c address range for devices
 */
void em28xx_do_i2c_scan(struct em28xx *dev)
{
        u8 i2c_devicelist[128];
        unsigned char buf;
        int i, rc;

        memset(i2c_devicelist, 0, ARRAY_SIZE(i2c_devicelist));

        for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
                dev->i2c_client.addr = i;
                rc = i2c_master_recv(&dev->i2c_client, &buf, 0);
                if (rc < 0)
                        continue;
                i2c_devicelist[i] = i;
                printk(KERN_INFO "%s: found i2c device @ 0x%x [%s]\n",
                       dev->name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
        }

        dev->i2c_hash = em28xx_hash_mem(i2c_devicelist,
                                        ARRAY_SIZE(i2c_devicelist), 32);
}

/*
 * em28xx_i2c_register()
 * register i2c bus
 */
int em28xx_i2c_register(struct em28xx *dev)
{
        int retval;

        BUG_ON(!dev->em28xx_write_regs || !dev->em28xx_read_reg);
        BUG_ON(!dev->em28xx_write_regs_req || !dev->em28xx_read_reg_req);
        dev->i2c_adap = em28xx_adap_template;
        dev->i2c_adap.dev.parent = &dev->udev->dev;
        strcpy(dev->i2c_adap.name, dev->name);
        dev->i2c_adap.algo_data = dev;
        i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);

        retval = i2c_add_adapter(&dev->i2c_adap);
        if (retval < 0) {
                em28xx_errdev("%s: i2c_add_adapter failed! retval [%d]\n",
                        __func__, retval);
                return retval;
        }

        dev->i2c_client = em28xx_client_template;
        dev->i2c_client.adapter = &dev->i2c_adap;

        retval = em28xx_i2c_eeprom(dev, dev->eedata, sizeof(dev->eedata));
        if ((retval < 0) && (retval != -ENODEV)) {
                em28xx_errdev("%s: em28xx_i2_eeprom failed! retval [%d]\n",
                        __func__, retval);

                return retval;
        }

        if (i2c_scan)
                em28xx_do_i2c_scan(dev);

        /* Instantiate the IR receiver device, if present */
        em28xx_register_i2c_ir(dev);

        return 0;
}

/*
 * em28xx_i2c_unregister()
 * unregister i2c_bus
 */
int em28xx_i2c_unregister(struct em28xx *dev)
{
        i2c_del_adapter(&dev->i2c_adap);
        return 0;
}