/*
    Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>,
    Philip Edelbrock <phil@netroedge.com>,
    Ralph Metzler <rjkm@thp.uni-koeln.de>, and
    Mark D. Studebaker <mdsxyz123@yahoo.com>
    
    Based on code written by Ralph Metzler <rjkm@thp.uni-koeln.de> and
    Simon Vogl

    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.
*/

/* This interfaces to the I2C bus of the Voodoo3 to gain access to
    the BT869 and possibly other I2C devices. */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <asm/io.h>

/* the only registers we use */
#define REG             0x78
#define REG2            0x70

/* bit locations in the register */
#define DDC_ENAB        0x00040000
#define DDC_SCL_OUT     0x00080000
#define DDC_SDA_OUT     0x00100000
#define DDC_SCL_IN      0x00200000
#define DDC_SDA_IN      0x00400000
#define I2C_ENAB        0x00800000
#define I2C_SCL_OUT     0x01000000
#define I2C_SDA_OUT     0x02000000
#define I2C_SCL_IN      0x04000000
#define I2C_SDA_IN      0x08000000

/* initialization states */
#define INIT2           0x2
#define INIT3           0x4

/* delays */
#define CYCLE_DELAY     10
#define TIMEOUT         (HZ / 2)


static void __iomem *ioaddr;

/* The voo GPIO registers don't have individual masks for each bit
   so we always have to read before writing. */

static void bit_vooi2c_setscl(void *data, int val)
{
        unsigned int r;
        r = readl(ioaddr + REG);
        if (val)
                r |= I2C_SCL_OUT;
        else
                r &= ~I2C_SCL_OUT;
        writel(r, ioaddr + REG);
        readl(ioaddr + REG);    /* flush posted write */
}

static void bit_vooi2c_setsda(void *data, int val)
{
        unsigned int r;
        r = readl(ioaddr + REG);
        if (val)
                r |= I2C_SDA_OUT;
        else
                r &= ~I2C_SDA_OUT;
        writel(r, ioaddr + REG);
        readl(ioaddr + REG);    /* flush posted write */
}

/* The GPIO pins are open drain, so the pins always remain outputs.
   We rely on the i2c-algo-bit routines to set the pins high before
   reading the input from other chips. */

static int bit_vooi2c_getscl(void *data)
{
        return (0 != (readl(ioaddr + REG) & I2C_SCL_IN));
}

static int bit_vooi2c_getsda(void *data)
{
        return (0 != (readl(ioaddr + REG) & I2C_SDA_IN));
}

static void bit_vooddc_setscl(void *data, int val)
{
        unsigned int r;
        r = readl(ioaddr + REG);
        if (val)
                r |= DDC_SCL_OUT;
        else
                r &= ~DDC_SCL_OUT;
        writel(r, ioaddr + REG);
        readl(ioaddr + REG);    /* flush posted write */
}

static void bit_vooddc_setsda(void *data, int val)
{
        unsigned int r;
        r = readl(ioaddr + REG);
        if (val)
                r |= DDC_SDA_OUT;
        else
                r &= ~DDC_SDA_OUT;
        writel(r, ioaddr + REG);
        readl(ioaddr + REG);    /* flush posted write */
}

static int bit_vooddc_getscl(void *data)
{
        return (0 != (readl(ioaddr + REG) & DDC_SCL_IN));
}

static int bit_vooddc_getsda(void *data)
{
        return (0 != (readl(ioaddr + REG) & DDC_SDA_IN));
}

static int config_v3(struct pci_dev *dev)
{
        unsigned long cadr;

        /* map Voodoo3 memory */
        cadr = dev->resource[0].start;
        cadr &= PCI_BASE_ADDRESS_MEM_MASK;
        ioaddr = ioremap_nocache(cadr, 0x1000);
        if (ioaddr) {
                writel(0x8160, ioaddr + REG2);
                writel(0xcffc0020, ioaddr + REG);
                dev_info(&dev->dev, "Using Banshee/Voodoo3 I2C device at %p\n", ioaddr);
                return 0;
        }
        return -ENODEV;
}

static struct i2c_algo_bit_data voo_i2c_bit_data = {
        .setsda         = bit_vooi2c_setsda,
        .setscl         = bit_vooi2c_setscl,
        .getsda         = bit_vooi2c_getsda,
        .getscl         = bit_vooi2c_getscl,
        .udelay         = CYCLE_DELAY,
        .timeout        = TIMEOUT
};

static struct i2c_adapter voodoo3_i2c_adapter = {
        .owner          = THIS_MODULE,
        .name           = "I2C Voodoo3/Banshee adapter",
        .algo_data      = &voo_i2c_bit_data,
};

static struct i2c_algo_bit_data voo_ddc_bit_data = {
        .setsda         = bit_vooddc_setsda,
        .setscl         = bit_vooddc_setscl,
        .getsda         = bit_vooddc_getsda,
        .getscl         = bit_vooddc_getscl,
        .udelay         = CYCLE_DELAY,
        .timeout        = TIMEOUT
};

static struct i2c_adapter voodoo3_ddc_adapter = {
        .owner          = THIS_MODULE,
        .class          = I2C_CLASS_DDC, 
        .name           = "DDC Voodoo3/Banshee adapter",
        .algo_data      = &voo_ddc_bit_data,
};

static struct pci_device_id voodoo3_ids[] __devinitdata = {
        { PCI_DEVICE(PCI_VENDOR_ID_3DFX, PCI_DEVICE_ID_3DFX_VOODOO3) },
        { PCI_DEVICE(PCI_VENDOR_ID_3DFX, PCI_DEVICE_ID_3DFX_BANSHEE) },
        { 0, }
};

MODULE_DEVICE_TABLE (pci, voodoo3_ids);

static int __devinit voodoo3_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
        int retval;

        retval = config_v3(dev);
        if (retval)
                return retval;

        /* set up the sysfs linkage to our parent device */
        voodoo3_i2c_adapter.dev.parent = &dev->dev;
        voodoo3_ddc_adapter.dev.parent = &dev->dev;

        retval = i2c_bit_add_bus(&voodoo3_i2c_adapter);
        if (retval)
                return retval;
        retval = i2c_bit_add_bus(&voodoo3_ddc_adapter);
        if (retval)
                i2c_del_adapter(&voodoo3_i2c_adapter);
        return retval;
}

static void __devexit voodoo3_remove(struct pci_dev *dev)
{
        i2c_del_adapter(&voodoo3_i2c_adapter);
        i2c_del_adapter(&voodoo3_ddc_adapter);
        iounmap(ioaddr);
}

static struct pci_driver voodoo3_driver = {
        .name           = "voodoo3_smbus",
        .id_table       = voodoo3_ids,
        .probe          = voodoo3_probe,
        .remove         = __devexit_p(voodoo3_remove),
};

static int __init i2c_voodoo3_init(void)
{
        return pci_register_driver(&voodoo3_driver);
}

static void __exit i2c_voodoo3_exit(void)
{
        pci_unregister_driver(&voodoo3_driver);
}


MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>, "
                "Philip Edelbrock <phil@netroedge.com>, "
                "Ralph Metzler <rjkm@thp.uni-koeln.de>, "
                "and Mark D. Studebaker <mdsxyz123@yahoo.com>");
MODULE_DESCRIPTION("Voodoo3 I2C/SMBus driver");
MODULE_LICENSE("GPL");

module_init(i2c_voodoo3_init);
module_exit(i2c_voodoo3_exit);