i2c-via.c

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/*
    i2c Support for Via Technologies 82C586B South Bridge

    Copyright (c) 1998, 1999 Kyösti Mälkki <[email protected]>

    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/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 <linux/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

static struct pci_driver vt586b_driver;
static u16 pm_io_base;

/*
   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,
    .timeout    = HZ
};

static struct i2c_adapter vt586b_adapter = {
    .owner      = THIS_MODULE,
    .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
    .name       = "VIA i2c",
    .algo_data  = &bit_data,
};


static DEFINE_PCI_DEVICE_TABLE(vt586b_ids) = {
    { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
    { 0, }
};

MODULE_DEVICE_TABLE (pci, vt586b_ids);

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, vt586b_driver.name)) {
        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 sysfs 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_del_adapter(&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),
};

module_pci_driver(vt586b_driver);

MODULE_AUTHOR("Kyösti Mälkki <[email protected]>");
MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
MODULE_LICENSE("GPL");