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/*

    i2c-via.c - Part of lm_sensors,  Linux kernel modules

                for hardware monitoring

    i2c Support for Via Technologies 82C586B South Bridge

    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>

    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.

*/

#define DEBUG

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/ioport.h>

#include <linux/init.h>

#include <linux/i2c.h>

#include <linux/i2c-algo-bit.h>

#include <asm/io.h>

/* Power management registers */

#define PM_CFG_REVID    0x08    /* silicon revision code */

#define PM_CFG_IOBASE0  0x20

#define PM_CFG_IOBASE1  0x48

#define I2C_DIR         (pm_io_base+0x40)

#define I2C_OUT         (pm_io_base+0x42)

#define I2C_IN          (pm_io_base+0x44)

#define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */

#define I2C_SDA         0x04

/* io-region reservation */

#define IOSPACE         0x06

#define IOTEXT          "via-i2c"

static u16 pm_io_base = 0;

/*

   It does not appear from the datasheet that the GPIO pins are

   open drain. So a we set a low value by setting the direction to

   output and a high value by setting the direction to input and

   relying on the required I2C pullup. The data value is initialized

   to 0 in via_init() and never changed.

*/

static void bit_via_setscl(void *data, int state)

{

        outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);

}

static void bit_via_setsda(void *data, int state)

{

        outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);

}

static int bit_via_getscl(void *data)

{

        return (0 != (inb(I2C_IN) & I2C_SCL));

}

static int bit_via_getsda(void *data)

{

        return (0 != (inb(I2C_IN) & I2C_SDA));

}

static struct i2c_algo_bit_data bit_data = {

        .setsda         = bit_via_setsda,

        .setscl         = bit_via_setscl,

        .getsda         = bit_via_getsda,

        .getscl         = bit_via_getscl,

        .udelay         = 5,

        .mdelay         = 5,

        .timeout        = HZ

};

static struct i2c_adapter vt586b_adapter = {

        .owner          = THIS_MODULE,

        .name           = "VIA i2c",

        .algo_data      = &bit_data,

};

static struct pci_device_id vt586b_ids[] __devinitdata = {

        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },

        { 0, }

};

static int __devinit vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)

{

        u16 base;

        u8 rev;

        int res;

        if (pm_io_base) {

                dev_err(&dev->dev, "i2c-via: Will only support one host\n");

                return -ENODEV;

        }

        pci_read_config_byte(dev, PM_CFG_REVID, &rev);

        switch (rev) {

        case 0x00:

                base = PM_CFG_IOBASE0;

                break;

        case 0x01:

        case 0x10:

                base = PM_CFG_IOBASE1;

                break;

        default:

                base = PM_CFG_IOBASE1;

                /* later revision */

        }

        pci_read_config_word(dev, base, &pm_io_base);

        pm_io_base &= (0xff << 8);

        if (!request_region(I2C_DIR, IOSPACE, IOTEXT)) {

                dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);

                return -ENODEV;

        }

        outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);

        outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);

        /* set up the driverfs linkage to our parent device */

        vt586b_adapter.dev.parent = &dev->dev;

        res = i2c_bit_add_bus(&vt586b_adapter);

        if ( res < 0 ) {

                release_region(I2C_DIR, IOSPACE);

                pm_io_base = 0;

                return res;

        }

        return 0;

}

static void __devexit vt586b_remove(struct pci_dev *dev)

{

        i2c_bit_del_bus(&vt586b_adapter);

        release_region(I2C_DIR, IOSPACE);

        pm_io_base = 0;

}

static struct pci_driver vt586b_driver = {

        .name           = "vt586b smbus",

        .id_table       = vt586b_ids,

        .probe          = vt586b_probe,

        .remove         = __devexit_p(vt586b_remove),

};

static int __init i2c_vt586b_init(void)

{

        return pci_module_init(&vt586b_driver);

}

static void __exit i2c_vt586b_exit(void)

{

        pci_unregister_driver(&vt586b_driver);

}

MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");

MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");

MODULE_LICENSE("GPL");

module_init(i2c_vt586b_init);

module_exit(i2c_vt586b_exit);