/*
 * usbvision_i2c.c
 *  i2c algorithm for USB-I2C Bridges
 *
 * Copyright (c) 1999-2007 Joerg Heckenbach <joerg@heckenbach-aw.de>
 *                         Dwaine Garden <dwainegarden@rogers.com>
 *
 * This module is part of usbvision driver project.
 * Updates to driver completed by Dwaine P. Garden
 *
 * 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.
 */


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include "usbvision.h"

#define DBG_I2C         (1 << 0)

static int i2c_debug;

module_param(i2c_debug, int, 0644);                     /* debug_i2c_usb mode of the device driver */
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

#define PDEBUG(level, fmt, args...) { \
                if (i2c_debug & (level)) \
                        printk(KERN_INFO KBUILD_MODNAME ":[%s:%d] " fmt, \
                                __func__, __LINE__ , ## args); \
        }

static int usbvision_i2c_write(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
                            short len);
static int usbvision_i2c_read(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
                           short len);

static inline int try_write_address(struct i2c_adapter *i2c_adap,
                                    unsigned char addr, int retries)
{
        struct usb_usbvision *usbvision;
        int i, ret = -1;
        char buf[4];

        usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);
        buf[0] = 0x00;
        for (i = 0; i <= retries; i++) {
                ret = (usbvision_i2c_write(usbvision, addr, buf, 1));
                if (ret == 1)
                        break;  /* success! */
                udelay(5);
                if (i == retries)       /* no success */
                        break;
                udelay(10);
        }
        if (i) {
                PDEBUG(DBG_I2C, "Needed %d retries for address %#2x", i, addr);
                PDEBUG(DBG_I2C, "Maybe there's no device at this address");
        }
        return ret;
}

static inline int try_read_address(struct i2c_adapter *i2c_adap,
                                   unsigned char addr, int retries)
{
        struct usb_usbvision *usbvision;
        int i, ret = -1;
        char buf[4];

        usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);
        for (i = 0; i <= retries; i++) {
                ret = (usbvision_i2c_read(usbvision, addr, buf, 1));
                if (ret == 1)
                        break;  /* success! */
                udelay(5);
                if (i == retries)       /* no success */
                        break;
                udelay(10);
        }
        if (i) {
                PDEBUG(DBG_I2C, "Needed %d retries for address %#2x", i, addr);
                PDEBUG(DBG_I2C, "Maybe there's no device at this address");
        }
        return ret;
}

static inline int usb_find_address(struct i2c_adapter *i2c_adap,
                                   struct i2c_msg *msg, int retries,
                                   unsigned char *add)
{
        unsigned short flags = msg->flags;

        unsigned char addr;
        int ret;

        addr = (msg->addr << 1);
        if (flags & I2C_M_RD)
                addr |= 1;

        add[0] = addr;
        if (flags & I2C_M_RD)
                ret = try_read_address(i2c_adap, addr, retries);
        else
                ret = try_write_address(i2c_adap, addr, retries);

        if (ret != 1)
                return -EREMOTEIO;

        return 0;
}

static int
usbvision_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
{
        struct i2c_msg *pmsg;
        struct usb_usbvision *usbvision;
        int i, ret;
        unsigned char addr = 0;

        usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);

        for (i = 0; i < num; i++) {
                pmsg = &msgs[i];
                ret = usb_find_address(i2c_adap, pmsg, i2c_adap->retries, &addr);
                if (ret != 0) {
                        PDEBUG(DBG_I2C, "got NAK from device, message #%d", i);
                        return (ret < 0) ? ret : -EREMOTEIO;
                }

                if (pmsg->flags & I2C_M_RD) {
                        /* read bytes into buffer */
                        ret = (usbvision_i2c_read(usbvision, addr, pmsg->buf, pmsg->len));
                        if (ret < pmsg->len)
                                return (ret < 0) ? ret : -EREMOTEIO;
                } else {
                        /* write bytes from buffer */
                        ret = (usbvision_i2c_write(usbvision, addr, pmsg->buf, pmsg->len));
                        if (ret < pmsg->len)
                                return (ret < 0) ? ret : -EREMOTEIO;
                }
        }
        return num;
}

static u32 functionality(struct i2c_adapter *adap)
{
        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

/* -----exported algorithm data: -------------------------------------  */

static const struct i2c_algorithm usbvision_algo = {
        .master_xfer   = usbvision_i2c_xfer,
        .smbus_xfer    = NULL,
        .functionality = functionality,
};


/* ----------------------------------------------------------------------- */
/* usbvision specific I2C functions                                        */
/* ----------------------------------------------------------------------- */
static const struct i2c_adapter i2c_adap_template;

int usbvision_i2c_register(struct usb_usbvision *usbvision)
{
        static unsigned short saa711x_addrs[] = {
                0x4a >> 1, 0x48 >> 1,   /* SAA7111, SAA7111A and SAA7113 */
                0x42 >> 1, 0x40 >> 1,   /* SAA7114, SAA7115 and SAA7118 */
                I2C_CLIENT_END };

        if (usbvision->registered_i2c)
                return 0;

        usbvision->i2c_adap = i2c_adap_template;

        snprintf(usbvision->i2c_adap.name, sizeof(usbvision->i2c_adap.name),
                 "usbvision-%d-%s",
                 usbvision->dev->bus->busnum, usbvision->dev->devpath);
        PDEBUG(DBG_I2C, "Adaptername: %s", usbvision->i2c_adap.name);
        usbvision->i2c_adap.dev.parent = &usbvision->dev->dev;

        i2c_set_adapdata(&usbvision->i2c_adap, &usbvision->v4l2_dev);

        if (usbvision_write_reg(usbvision, USBVISION_SER_MODE, USBVISION_IIC_LRNACK) < 0) {
                printk(KERN_ERR "usbvision_i2c_register: can't write reg\n");
                return -EBUSY;
        }

        PDEBUG(DBG_I2C, "I2C   debugging is enabled [i2c]");
        PDEBUG(DBG_I2C, "ALGO   debugging is enabled [i2c]");

        /* register new adapter to i2c module... */

        usbvision->i2c_adap.algo = &usbvision_algo;

        usbvision->i2c_adap.timeout = 100;      /* default values, should       */
        usbvision->i2c_adap.retries = 3;        /* be replaced by defines       */

        i2c_add_adapter(&usbvision->i2c_adap);

        PDEBUG(DBG_I2C, "i2c bus for %s registered", usbvision->i2c_adap.name);

        /* Request the load of the i2c modules we need */
        switch (usbvision_device_data[usbvision->dev_model].codec) {
        case CODEC_SAA7113:
        case CODEC_SAA7111:
                /* Without this delay the detection of the saa711x is
                   hit-and-miss. */
                mdelay(10);
                v4l2_i2c_new_subdev(&usbvision->v4l2_dev,
                                &usbvision->i2c_adap,
                                "saa7115_auto", 0, saa711x_addrs);
                break;
        }
        if (usbvision_device_data[usbvision->dev_model].tuner == 1) {
                struct v4l2_subdev *sd;
                enum v4l2_i2c_tuner_type type;
                struct tuner_setup tun_setup;

                sd = v4l2_i2c_new_subdev(&usbvision->v4l2_dev,
                                &usbvision->i2c_adap,
                                "tuner", 0, v4l2_i2c_tuner_addrs(ADDRS_DEMOD));
                /* depending on whether we found a demod or not, select
                   the tuner type. */
                type = sd ? ADDRS_TV_WITH_DEMOD : ADDRS_TV;

                sd = v4l2_i2c_new_subdev(&usbvision->v4l2_dev,
                                &usbvision->i2c_adap,
                                "tuner", 0, v4l2_i2c_tuner_addrs(type));

                if (sd == NULL)
                        return -ENODEV;
                if (usbvision->tuner_type != -1) {
                        tun_setup.mode_mask = T_ANALOG_TV | T_RADIO;
                        tun_setup.type = usbvision->tuner_type;
                        tun_setup.addr = v4l2_i2c_subdev_addr(sd);
                        call_all(usbvision, tuner, s_type_addr, &tun_setup);
                }
        }
        usbvision->registered_i2c = 1;

        return 0;
}

int usbvision_i2c_unregister(struct usb_usbvision *usbvision)
{
        if (!usbvision->registered_i2c)
                return 0;

        i2c_del_adapter(&(usbvision->i2c_adap));
        usbvision->registered_i2c = 0;

        PDEBUG(DBG_I2C, "i2c bus for %s unregistered", usbvision->i2c_adap.name);

        return 0;
}

static int
usbvision_i2c_read_max4(struct usb_usbvision *usbvision, unsigned char addr,
                     char *buf, short len)
{
        int rc, retries;

        for (retries = 5;;) {
                rc = usbvision_write_reg(usbvision, USBVISION_SER_ADRS, addr);
                if (rc < 0)
                        return rc;

                /* Initiate byte read cycle                    */
                /* USBVISION_SER_CONT <- d0-d2 n. of bytes to r/w */
                /*                    d3 0=Wr 1=Rd             */
                rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
                                      (len & 0x07) | 0x18);
                if (rc < 0)
                        return rc;

                /* Test for Busy and ACK */
                do {
                        /* USBVISION_SER_CONT -> d4 == 0 busy */
                        rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
                } while (rc > 0 && ((rc & 0x10) != 0)); /* Retry while busy */
                if (rc < 0)
                        return rc;

                /* USBVISION_SER_CONT -> d5 == 1 Not ack */
                if ((rc & 0x20) == 0)   /* Ack? */
                        break;

                /* I2C abort */
                rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);
                if (rc < 0)
                        return rc;

                if (--retries < 0)
                        return -1;
        }

        switch (len) {
        case 4:
                buf[3] = usbvision_read_reg(usbvision, USBVISION_SER_DAT4);
                /* fall through */
        case 3:
                buf[2] = usbvision_read_reg(usbvision, USBVISION_SER_DAT3);
                /* fall through */
        case 2:
                buf[1] = usbvision_read_reg(usbvision, USBVISION_SER_DAT2);
                /* fall through */
        case 1:
                buf[0] = usbvision_read_reg(usbvision, USBVISION_SER_DAT1);
                break;
        default:
                printk(KERN_ERR
                       "usbvision_i2c_read_max4: buffer length > 4\n");
        }

        if (i2c_debug & DBG_I2C) {
                int idx;

                for (idx = 0; idx < len; idx++)
                        PDEBUG(DBG_I2C, "read %x from address %x", (unsigned char)buf[idx], addr);
        }
        return len;
}


static int usbvision_i2c_write_max4(struct usb_usbvision *usbvision,
                                 unsigned char addr, const char *buf,
                                 short len)
{
        int rc, retries;
        int i;
        unsigned char *value = usbvision->ctrl_urb_buffer;
        unsigned char ser_cont;

        ser_cont = (len & 0x07) | 0x10;

        value[0] = addr;
        value[1] = ser_cont;
        for (i = 0; i < len; i++)
                value[i + 2] = buf[i];

        for (retries = 5;;) {
                rc = usb_control_msg(usbvision->dev,
                                     usb_sndctrlpipe(usbvision->dev, 1),
                                     USBVISION_OP_CODE,
                                     USB_DIR_OUT | USB_TYPE_VENDOR |
                                     USB_RECIP_ENDPOINT, 0,
                                     (__u16) USBVISION_SER_ADRS, value,
                                     len + 2, HZ);

                if (rc < 0)
                        return rc;

                rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
                                      (len & 0x07) | 0x10);
                if (rc < 0)
                        return rc;

                /* Test for Busy and ACK */
                do {
                        rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
                } while (rc > 0 && ((rc & 0x10) != 0)); /* Retry while busy */
                if (rc < 0)
                        return rc;

                if ((rc & 0x20) == 0)   /* Ack? */
                        break;

                /* I2C abort */
                usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);

                if (--retries < 0)
                        return -1;

        }

        if (i2c_debug & DBG_I2C) {
                int idx;

                for (idx = 0; idx < len; idx++)
                        PDEBUG(DBG_I2C, "wrote %x at address %x", (unsigned char)buf[idx], addr);
        }
        return len;
}

static int usbvision_i2c_write(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
                            short len)
{
        char *buf_ptr = buf;
        int retval;
        int wrcount = 0;
        int count;
        int max_len = 4;

        while (len > 0) {
                count = (len > max_len) ? max_len : len;
                retval = usbvision_i2c_write_max4(usbvision, addr, buf_ptr, count);
                if (retval > 0) {
                        len -= count;
                        buf_ptr += count;
                        wrcount += count;
                } else
                        return (retval < 0) ? retval : -EFAULT;
        }
        return wrcount;
}

static int usbvision_i2c_read(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
                           short len)
{
        char temp[4];
        int retval, i;
        int rdcount = 0;
        int count;

        while (len > 0) {
                count = (len > 3) ? 4 : len;
                retval = usbvision_i2c_read_max4(usbvision, addr, temp, count);
                if (retval > 0) {
                        for (i = 0; i < len; i++)
                                buf[rdcount + i] = temp[i];
                        len -= count;
                        rdcount += count;
                } else
                        return (retval < 0) ? retval : -EFAULT;
        }
        return rdcount;
}

static const struct i2c_adapter i2c_adap_template = {
        .owner = THIS_MODULE,
        .name              = "usbvision",
};