/* Shared Code for OmniVision Camera Chip Drivers
 *
 * Copyright (c) 2004 Mark McClelland <mark@alpha.dyndns.org>
 * http://alpha.dyndns.org/ov511/
 *
 * 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. NO WARRANTY OF ANY KIND is expressed or implied.
 */

#define DEBUG

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include "ovcamchip_priv.h"

#define DRIVER_VERSION "v2.27 for Linux 2.6"
#define DRIVER_AUTHOR "Mark McClelland <mark@alpha.dyndns.org>"
#define DRIVER_DESC "OV camera chip I2C driver"

#define PINFO(fmt, args...) printk(KERN_INFO "ovcamchip: " fmt "\n" , ## args);
#define PERROR(fmt, args...) printk(KERN_ERR "ovcamchip: " fmt "\n" , ## args);

#ifdef DEBUG
int ovcamchip_debug = 0;
static int debug;
module_param(debug, int, 0);
MODULE_PARM_DESC(debug,
  "Debug level: 0=none, 1=inits, 2=warning, 3=config, 4=functions, 5=all");
#endif

/* By default, let bridge driver tell us if chip is monochrome. mono=0
 * will ignore that and always treat chips as color. mono=1 will force
 * monochrome mode for all chips. */
static int mono = -1;
module_param(mono, int, 0);
MODULE_PARM_DESC(mono,
  "1=chips are monochrome (OVx1xx), 0=force color, -1=autodetect (default)");

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/* Registers common to all chips, that are needed for detection */
#define GENERIC_REG_ID_HIGH       0x1C  /* manufacturer ID MSB */
#define GENERIC_REG_ID_LOW        0x1D  /* manufacturer ID LSB */
#define GENERIC_REG_COM_I         0x29  /* misc ID bits */

extern struct ovcamchip_ops ov6x20_ops;
extern struct ovcamchip_ops ov6x30_ops;
extern struct ovcamchip_ops ov7x10_ops;
extern struct ovcamchip_ops ov7x20_ops;
extern struct ovcamchip_ops ov76be_ops;

static char *chip_names[NUM_CC_TYPES] = {
        [CC_UNKNOWN]    = "Unknown chip",
        [CC_OV76BE]     = "OV76BE",
        [CC_OV7610]     = "OV7610",
        [CC_OV7620]     = "OV7620",
        [CC_OV7620AE]   = "OV7620AE",
        [CC_OV6620]     = "OV6620",
        [CC_OV6630]     = "OV6630",
        [CC_OV6630AE]   = "OV6630AE",
        [CC_OV6630AF]   = "OV6630AF",
};

/* Forward declarations */
static struct i2c_driver driver;
static struct i2c_client client_template;

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

int ov_write_regvals(struct i2c_client *c, struct ovcamchip_regvals *rvals)
{
        int rc;

        while (rvals->reg != 0xff) {
                rc = ov_write(c, rvals->reg, rvals->val);
                if (rc < 0)
                        return rc;
                rvals++;
        }

        return 0;
}

/* Writes bits at positions specified by mask to an I2C reg. Bits that are in
 * the same position as 1's in "mask" are cleared and set to "value". Bits
 * that are in the same position as 0's in "mask" are preserved, regardless
 * of their respective state in "value".
 */
int ov_write_mask(struct i2c_client *c,
                  unsigned char reg,
                  unsigned char value,
                  unsigned char mask)
{
        int rc;
        unsigned char oldval, newval;

        if (mask == 0xff) {
                newval = value;
        } else {
                rc = ov_read(c, reg, &oldval);
                if (rc < 0)
                        return rc;

                oldval &= (~mask);              /* Clear the masked bits */
                value &= mask;                  /* Enforce mask on value */
                newval = oldval | value;        /* Set the desired bits */
        }

        return ov_write(c, reg, newval);
}

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

/* Reset the chip and ensure that I2C is synchronized. Returns <0 if failure.
 */
static int init_camchip(struct i2c_client *c)
{
        int i, success;
        unsigned char high, low;

        /* Reset the chip */
        ov_write(c, 0x12, 0x80);

        /* Wait for it to initialize */
        msleep(150);

        for (i = 0, success = 0; i < I2C_DETECT_RETRIES && !success; i++) {
                if (ov_read(c, GENERIC_REG_ID_HIGH, &high) >= 0) {
                        if (ov_read(c, GENERIC_REG_ID_LOW, &low) >= 0) {
                                if (high == 0x7F && low == 0xA2) {
                                        success = 1;
                                        continue;
                                }
                        }
                }

                /* Reset the chip */
                ov_write(c, 0x12, 0x80);

                /* Wait for it to initialize */
                msleep(150);

                /* Dummy read to sync I2C */
                ov_read(c, 0x00, &low);
        }

        if (!success)
                return -EIO;

        PDEBUG(1, "I2C synced in %d attempt(s)", i);

        return 0;
}

/* This detects the OV7610, OV7620, or OV76BE chip. */
static int ov7xx0_detect(struct i2c_client *c)
{
        struct ovcamchip *ov = i2c_get_clientdata(c);
        int rc;
        unsigned char val;

        PDEBUG(4, "");

        /* Detect chip (sub)type */
        rc = ov_read(c, GENERIC_REG_COM_I, &val);
        if (rc < 0) {
                PERROR("Error detecting ov7xx0 type");
                return rc;
        }

        if ((val & 3) == 3) {
                PINFO("Camera chip is an OV7610");
                ov->subtype = CC_OV7610;
        } else if ((val & 3) == 1) {
                rc = ov_read(c, 0x15, &val);
                if (rc < 0) {
                        PERROR("Error detecting ov7xx0 type");
                        return rc;
                }

                if (val & 1) {
                        PINFO("Camera chip is an OV7620AE");
                        /* OV7620 is a close enough match for now. There are
                         * some definite differences though, so this should be
                         * fixed */
                        ov->subtype = CC_OV7620;
                } else {
                        PINFO("Camera chip is an OV76BE");
                        ov->subtype = CC_OV76BE;
                }
        } else if ((val & 3) == 0) {
                PINFO("Camera chip is an OV7620");
                ov->subtype = CC_OV7620;
        } else {
                PERROR("Unknown camera chip version: %d", val & 3);
                return -ENOSYS;
        }

        if (ov->subtype == CC_OV76BE)
                ov->sops = &ov76be_ops;
        else if (ov->subtype == CC_OV7620)
                ov->sops = &ov7x20_ops;
        else
                ov->sops = &ov7x10_ops;

        return 0;
}

/* This detects the OV6620, OV6630, OV6630AE, or OV6630AF chip. */
static int ov6xx0_detect(struct i2c_client *c)
{
        struct ovcamchip *ov = i2c_get_clientdata(c);
        int rc;
        unsigned char val;

        PDEBUG(4, "");

        /* Detect chip (sub)type */
        rc = ov_read(c, GENERIC_REG_COM_I, &val);
        if (rc < 0) {
                PERROR("Error detecting ov6xx0 type");
                return -1;
        }

        if ((val & 3) == 0) {
                ov->subtype = CC_OV6630;
                PINFO("Camera chip is an OV6630");
        } else if ((val & 3) == 1) {
                ov->subtype = CC_OV6620;
                PINFO("Camera chip is an OV6620");
        } else if ((val & 3) == 2) {
                ov->subtype = CC_OV6630;
                PINFO("Camera chip is an OV6630AE");
        } else if ((val & 3) == 3) {
                ov->subtype = CC_OV6630;
                PINFO("Camera chip is an OV6630AF");
        }

        if (ov->subtype == CC_OV6620)
                ov->sops = &ov6x20_ops;
        else
                ov->sops = &ov6x30_ops;

        return 0;
}

static int ovcamchip_detect(struct i2c_client *c)
{
        /* Ideally we would just try a single register write and see if it NAKs.
         * That isn't possible since the OV518 can't report I2C transaction
         * failures. So, we have to try to initialize the chip (i.e. reset it
         * and check the ID registers) to detect its presence. */

        /* Test for 7xx0 */
        PDEBUG(3, "Testing for 0V7xx0");
        c->addr = OV7xx0_SID;
        if (init_camchip(c) < 0) {
                /* Test for 6xx0 */
                PDEBUG(3, "Testing for 0V6xx0");
                c->addr = OV6xx0_SID;
                if (init_camchip(c) < 0) {
                        return -ENODEV;
                } else {
                        if (ov6xx0_detect(c) < 0) {
                                PERROR("Failed to init OV6xx0");
                                return -EIO;
                        }
                }
        } else {
                if (ov7xx0_detect(c) < 0) {
                        PERROR("Failed to init OV7xx0");
                        return -EIO;
                }
        }

        return 0;
}

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

static int ovcamchip_attach(struct i2c_adapter *adap)
{
        int rc = 0;
        struct ovcamchip *ov;
        struct i2c_client *c;

        /* I2C is not a PnP bus, so we can never be certain that we're talking
         * to the right chip. To prevent damage to EEPROMS and such, only
         * attach to adapters that are known to contain OV camera chips. */

        switch (adap->id) {
        case I2C_HW_SMBUS_OV511:
        case I2C_HW_SMBUS_OV518:
        case I2C_HW_SMBUS_OVFX2:
        case I2C_HW_SMBUS_W9968CF:
                PDEBUG(1, "Adapter ID 0x%06x accepted", adap->id);
                break;
        default:
                PDEBUG(1, "Adapter ID 0x%06x rejected", adap->id);
                return -ENODEV;
        }

        c = kmalloc(sizeof *c, GFP_KERNEL);
        if (!c) {
                rc = -ENOMEM;
                goto no_client;
        }
        memcpy(c, &client_template, sizeof *c);
        c->adapter = adap;
        strcpy(c->name, "OV????");

        ov = kzalloc(sizeof *ov, GFP_KERNEL);
        if (!ov) {
                rc = -ENOMEM;
                goto no_ov;
        }
        i2c_set_clientdata(c, ov);

        rc = ovcamchip_detect(c);
        if (rc < 0)
                goto error;

        strcpy(c->name, chip_names[ov->subtype]);

        PDEBUG(1, "Camera chip detection complete");

        i2c_attach_client(c);

        return rc;
error:
        kfree(ov);
no_ov:
        kfree(c);
no_client:
        PDEBUG(1, "returning %d", rc);
        return rc;
}

static int ovcamchip_detach(struct i2c_client *c)
{
        struct ovcamchip *ov = i2c_get_clientdata(c);
        int rc;

        rc = ov->sops->free(c);
        if (rc < 0)
                return rc;

        i2c_detach_client(c);

        kfree(ov);
        kfree(c);
        return 0;
}

static int ovcamchip_command(struct i2c_client *c, unsigned int cmd, void *arg)
{
        struct ovcamchip *ov = i2c_get_clientdata(c);

        if (!ov->initialized &&
            cmd != OVCAMCHIP_CMD_Q_SUBTYPE &&
            cmd != OVCAMCHIP_CMD_INITIALIZE) {
                dev_err(&c->dev, "ERROR: Camera chip not initialized yet!\n");
                return -EPERM;
        }

        switch (cmd) {
        case OVCAMCHIP_CMD_Q_SUBTYPE:
        {
                *(int *)arg = ov->subtype;
                return 0;
        }
        case OVCAMCHIP_CMD_INITIALIZE:
        {
                int rc;

                if (mono == -1)
                        ov->mono = *(int *)arg;
                else
                        ov->mono = mono;

                if (ov->mono) {
                        if (ov->subtype != CC_OV7620)
                                dev_warn(&c->dev, "Warning: Monochrome not "
                                        "implemented for this chip\n");
                        else
                                dev_info(&c->dev, "Initializing chip as "
                                        "monochrome\n");
                }

                rc = ov->sops->init(c);
                if (rc < 0)
                        return rc;

                ov->initialized = 1;
                return 0;
        }
        default:
                return ov->sops->command(c, cmd, arg);
        }
}

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

static struct i2c_driver driver = {
        .driver = {
                .name =         "ovcamchip",
        },
        .id =                   I2C_DRIVERID_OVCAMCHIP,
        .class =                I2C_CLASS_CAM_DIGITAL,
        .attach_adapter =       ovcamchip_attach,
        .detach_client =        ovcamchip_detach,
        .command =              ovcamchip_command,
};

static struct i2c_client client_template = {
        .name =         "(unset)",
        .driver =       &driver,
};

static int __init ovcamchip_init(void)
{
#ifdef DEBUG
        ovcamchip_debug = debug;
#endif

        PINFO(DRIVER_VERSION " : " DRIVER_DESC);
        return i2c_add_driver(&driver);
}

static void __exit ovcamchip_exit(void)
{
        i2c_del_driver(&driver);
}

module_init(ovcamchip_init);
module_exit(ovcamchip_exit);