/*
   cx231xx-i2c.c - driver for Conexant Cx23100/101/102 USB video capture devices

   Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
                Based on em28xx driver
                Based on Cx23885 driver

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

#include "cx231xx.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)

/*
 * cx231xx_i2c_send_bytes()
 */
int cx231xx_i2c_send_bytes(struct i2c_adapter *i2c_adap,
                           const struct i2c_msg *msg)
{
        struct cx231xx_i2c *bus = i2c_adap->algo_data;
        struct cx231xx *dev = bus->dev;
        struct cx231xx_i2c_xfer_data req_data;
        int status = 0;
        u16 size = 0;
        u8 loop = 0;
        u8 saddr_len = 1;
        u8 *buf_ptr = NULL;
        u16 saddr = 0;
        u8 need_gpio = 0;

        if ((bus->nr == 1) && (msg->addr == 0x61)
            && (dev->tuner_type == TUNER_XC5000)) {

                size = msg->len;

                if (size == 2) {        /* register write sub addr */
                        /* Just writing sub address will cause problem
                        * to XC5000. So ignore the request */
                        return 0;
                } else if (size == 4) { /* register write with sub addr */
                        if (msg->len >= 2)
                                saddr = msg->buf[0] << 8 | msg->buf[1];
                        else if (msg->len == 1)
                                saddr = msg->buf[0];

                        switch (saddr) {
                        case 0x0000:    /* start tuner calibration mode */
                                need_gpio = 1;
                                /* FW Loading is done */
                                dev->xc_fw_load_done = 1;
                                break;
                        case 0x000D:    /* Set signal source */
                        case 0x0001:    /* Set TV standard - Video */
                        case 0x0002:    /* Set TV standard - Audio */
                        case 0x0003:    /* Set RF Frequency */
                                need_gpio = 1;
                                break;
                        default:
                                if (dev->xc_fw_load_done)
                                        need_gpio = 1;
                                break;
                        }

                        if (need_gpio) {
                                dprintk1(1,
                                "GPIO WRITE: addr 0x%x, len %d, saddr 0x%x\n",
                                msg->addr, msg->len, saddr);

                                return dev->cx231xx_gpio_i2c_write(dev,
                                                                   msg->addr,
                                                                   msg->buf,
                                                                   msg->len);
                        }
                }

                /* special case for Xc5000 tuner case */
                saddr_len = 1;

                /* adjust the length to correct length */
                size -= saddr_len;
                buf_ptr = (u8 *) (msg->buf + 1);

                do {
                        /* prepare xfer_data struct */
                        req_data.dev_addr = msg->addr;
                        req_data.direction = msg->flags;
                        req_data.saddr_len = saddr_len;
                        req_data.saddr_dat = msg->buf[0];
                        req_data.buf_size = size > 16 ? 16 : size;
                        req_data.p_buffer = (u8 *) (buf_ptr + loop * 16);

                        bus->i2c_nostop = (size > 16) ? 1 : 0;
                        bus->i2c_reserve = (loop == 0) ? 0 : 1;

                        /* usb send command */
                        status = dev->cx231xx_send_usb_command(bus, &req_data);
                        loop++;

                        if (size >= 16)
                                size -= 16;
                        else
                                size = 0;

                } while (size > 0);

                bus->i2c_nostop = 0;
                bus->i2c_reserve = 0;

        } else {                /* regular case */

                /* prepare xfer_data struct */
                req_data.dev_addr = msg->addr;
                req_data.direction = msg->flags;
                req_data.saddr_len = 0;
                req_data.saddr_dat = 0;
                req_data.buf_size = msg->len;
                req_data.p_buffer = msg->buf;

                /* usb send command */
                status = dev->cx231xx_send_usb_command(bus, &req_data);
        }

        return status < 0 ? status : 0;
}

/*
 * cx231xx_i2c_recv_bytes()
 * read a byte from the i2c device
 */
static int cx231xx_i2c_recv_bytes(struct i2c_adapter *i2c_adap,
                                  const struct i2c_msg *msg)
{
        struct cx231xx_i2c *bus = i2c_adap->algo_data;
        struct cx231xx *dev = bus->dev;
        struct cx231xx_i2c_xfer_data req_data;
        int status = 0;
        u16 saddr = 0;
        u8 need_gpio = 0;

        if ((bus->nr == 1) && (msg->addr == 0x61)
            && dev->tuner_type == TUNER_XC5000) {

                if (msg->len == 2)
                        saddr = msg->buf[0] << 8 | msg->buf[1];
                else if (msg->len == 1)
                        saddr = msg->buf[0];

                if (dev->xc_fw_load_done) {

                        switch (saddr) {
                        case 0x0009:    /* BUSY check */
                                dprintk1(1,
                                "GPIO R E A D: Special case BUSY check \n");
                                /*Try read BUSY register, just set it to zero*/
                                msg->buf[0] = 0;
                                if (msg->len == 2)
                                        msg->buf[1] = 0;
                                return 0;
                        case 0x0004:    /* read Lock status */
                                need_gpio = 1;
                                break;

                        }

                        if (need_gpio) {
                                /* this is a special case to handle Xceive tuner
                                clock stretch issue with gpio based I2C */

                                dprintk1(1,
                                "GPIO R E A D: addr 0x%x, len %d, saddr 0x%x\n",
                                msg->addr, msg->len,
                                msg->buf[0] << 8 | msg->buf[1]);

                                status =
                                    dev->cx231xx_gpio_i2c_write(dev, msg->addr,
                                                                msg->buf,
                                                                msg->len);
                                status =
                                    dev->cx231xx_gpio_i2c_read(dev, msg->addr,
                                                               msg->buf,
                                                               msg->len);
                                return status;
                        }
                }

                /* prepare xfer_data struct */
                req_data.dev_addr = msg->addr;
                req_data.direction = msg->flags;
                req_data.saddr_len = msg->len;
                req_data.saddr_dat = msg->buf[0] << 8 | msg->buf[1];
                req_data.buf_size = msg->len;
                req_data.p_buffer = msg->buf;

                /* usb send command */
                status = dev->cx231xx_send_usb_command(bus, &req_data);

        } else {

                /* prepare xfer_data struct */
                req_data.dev_addr = msg->addr;
                req_data.direction = msg->flags;
                req_data.saddr_len = 0;
                req_data.saddr_dat = 0;
                req_data.buf_size = msg->len;
                req_data.p_buffer = msg->buf;

                /* usb send command */
                status = dev->cx231xx_send_usb_command(bus, &req_data);
        }

        return status < 0 ? status : 0;
}

/*
 * cx231xx_i2c_recv_bytes_with_saddr()
 * read a byte from the i2c device
 */
static int cx231xx_i2c_recv_bytes_with_saddr(struct i2c_adapter *i2c_adap,
                                             const struct i2c_msg *msg1,
                                             const struct i2c_msg *msg2)
{
        struct cx231xx_i2c *bus = i2c_adap->algo_data;
        struct cx231xx *dev = bus->dev;
        struct cx231xx_i2c_xfer_data req_data;
        int status = 0;
        u16 saddr = 0;
        u8 need_gpio = 0;

        if (msg1->len == 2)
                saddr = msg1->buf[0] << 8 | msg1->buf[1];
        else if (msg1->len == 1)
                saddr = msg1->buf[0];

        if ((bus->nr == 1) && (msg2->addr == 0x61)
            && dev->tuner_type == TUNER_XC5000) {

                if ((msg2->len < 16)) {

                        dprintk1(1,
                        "i2c_read: addr 0x%x, len %d, saddr 0x%x, len %d\n",
                        msg2->addr, msg2->len, saddr, msg1->len);

                        switch (saddr) {
                        case 0x0008:    /* read FW load status */
                                need_gpio = 1;
                                break;
                        case 0x0004:    /* read Lock status */
                                need_gpio = 1;
                                break;
                        }

                        if (need_gpio) {
                                status =
                                    dev->cx231xx_gpio_i2c_write(dev, msg1->addr,
                                                                msg1->buf,
                                                                msg1->len);
                                status =
                                    dev->cx231xx_gpio_i2c_read(dev, msg2->addr,
                                                               msg2->buf,
                                                               msg2->len);
                                return status;
                        }
                }
        }

        /* prepare xfer_data struct */
        req_data.dev_addr = msg2->addr;
        req_data.direction = msg2->flags;
        req_data.saddr_len = msg1->len;
        req_data.saddr_dat = saddr;
        req_data.buf_size = msg2->len;
        req_data.p_buffer = msg2->buf;

        /* usb send command */
        status = dev->cx231xx_send_usb_command(bus, &req_data);

        return status < 0 ? status : 0;
}

/*
 * cx231xx_i2c_check_for_device()
 * check if there is a i2c_device at the supplied address
 */
static int cx231xx_i2c_check_for_device(struct i2c_adapter *i2c_adap,
                                        const struct i2c_msg *msg)
{
        struct cx231xx_i2c *bus = i2c_adap->algo_data;
        struct cx231xx *dev = bus->dev;
        struct cx231xx_i2c_xfer_data req_data;
        int status = 0;

        /* prepare xfer_data struct */
        req_data.dev_addr = msg->addr;
        req_data.direction = msg->flags;
        req_data.saddr_len = 0;
        req_data.saddr_dat = 0;
        req_data.buf_size = 0;
        req_data.p_buffer = NULL;

        /* usb send command */
        status = dev->cx231xx_send_usb_command(bus, &req_data);

        return status < 0 ? status : 0;
}

/*
 * cx231xx_i2c_xfer()
 * the main i2c transfer function
 */
static int cx231xx_i2c_xfer(struct i2c_adapter *i2c_adap,
                            struct i2c_msg msgs[], int num)
{
        struct cx231xx_i2c *bus = i2c_adap->algo_data;
        struct cx231xx *dev = bus->dev;
        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 */
                        rc = cx231xx_i2c_check_for_device(i2c_adap, &msgs[i]);
                        if (rc < 0) {
                                dprintk2(2, " no device\n");
                                return rc;
                        }

                } else if (msgs[i].flags & I2C_M_RD) {
                        /* read bytes */
                        rc = cx231xx_i2c_recv_bytes(i2c_adap, &msgs[i]);
                        if (i2c_debug >= 2) {
                                for (byte = 0; byte < msgs[i].len; byte++)
                                        printk(" %02x", msgs[i].buf[byte]);
                        }
                } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
                           msgs[i].addr == msgs[i + 1].addr
                           && (msgs[i].len <= 2) && (bus->nr < 2)) {
                        /* read bytes */
                        rc = cx231xx_i2c_recv_bytes_with_saddr(i2c_adap,
                                                               &msgs[i],
                                                               &msgs[i + 1]);
                        if (i2c_debug >= 2) {
                                for (byte = 0; byte < msgs[i].len; byte++)
                                        printk(" %02x", msgs[i].buf[byte]);
                        }
                        i++;
                } else {
                        /* write bytes */
                        if (i2c_debug >= 2) {
                                for (byte = 0; byte < msgs[i].len; byte++)
                                        printk(" %02x", msgs[i].buf[byte]);
                        }
                        rc = cx231xx_i2c_send_bytes(i2c_adap, &msgs[i]);
                }
                if (rc < 0)
                        goto err;
                if (i2c_debug >= 2)
                        printk("\n");
        }

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

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

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

static struct i2c_algorithm cx231xx_algo = {
        .master_xfer = cx231xx_i2c_xfer,
        .functionality = functionality,
};

static struct i2c_adapter cx231xx_adap_template = {
        .owner = THIS_MODULE,
        .name = "cx231xx",
        .algo = &cx231xx_algo,
};

static struct i2c_client cx231xx_client_template = {
        .name = "cx231xx internal",
};

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

/*
 * i2c_devs
 * incomplete list of known devices
 */
static char *i2c_devs[128] = {
        [0x60 >> 1] = "colibri",
        [0x88 >> 1] = "hammerhead",
        [0x8e >> 1] = "CIR",
        [0x32 >> 1] = "GeminiIII",
        [0x02 >> 1] = "Aquarius",
        [0xa0 >> 1] = "eeprom",
        [0xc0 >> 1] = "tuner/XC3028",
        [0xc2 >> 1] = "tuner/XC5000",
};

/*
 * cx231xx_do_i2c_scan()
 * check i2c address range for devices
 */
void cx231xx_do_i2c_scan(struct cx231xx *dev, struct i2c_client *c)
{
        unsigned char buf;
        int i, rc;

        cx231xx_info(": Checking for I2C devices ..\n");
        for (i = 0; i < 128; i++) {
                c->addr = i;
                rc = i2c_master_recv(c, &buf, 0);
                if (rc < 0)
                        continue;
                cx231xx_info("%s: i2c scan: found device @ 0x%x  [%s]\n",
                             dev->name, i << 1,
                             i2c_devs[i] ? i2c_devs[i] : "???");
        }
        cx231xx_info(": Completed Checking for I2C devices.\n");
}

/*
 * cx231xx_i2c_register()
 * register i2c bus
 */
int cx231xx_i2c_register(struct cx231xx_i2c *bus)
{
        struct cx231xx *dev = bus->dev;

        BUG_ON(!dev->cx231xx_send_usb_command);

        memcpy(&bus->i2c_adap, &cx231xx_adap_template, sizeof(bus->i2c_adap));
        memcpy(&bus->i2c_algo, &cx231xx_algo, sizeof(bus->i2c_algo));
        memcpy(&bus->i2c_client, &cx231xx_client_template,
               sizeof(bus->i2c_client));

        bus->i2c_adap.dev.parent = &dev->udev->dev;

        strlcpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));

        bus->i2c_algo.data = bus;
        bus->i2c_adap.algo_data = bus;
        i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
        i2c_add_adapter(&bus->i2c_adap);

        bus->i2c_client.adapter = &bus->i2c_adap;

        if (0 == bus->i2c_rc) {
                if (i2c_scan)
                        cx231xx_do_i2c_scan(dev, &bus->i2c_client);

                /* Instantiate the IR receiver device, if present */
                cx231xx_register_i2c_ir(dev);
        } else
                cx231xx_warn("%s: i2c bus %d register FAILED\n",
                             dev->name, bus->nr);

        return bus->i2c_rc;
}

/*
 * cx231xx_i2c_unregister()
 * unregister i2c_bus
 */
int cx231xx_i2c_unregister(struct cx231xx_i2c *bus)
{
        i2c_del_adapter(&bus->i2c_adap);
        return 0;
}