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420 giacomo 1
/*
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    i2c-via.c - Part of lm_sensors,  Linux kernel modules
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                for hardware monitoring
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    i2c Support for Via Technologies 82C586B South Bridge
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    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
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    This program is free software; you can redistribute it and/or modify
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    it under the terms of the GNU General Public License as published by
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    the Free Software Foundation; either version 2 of the License, or
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    (at your option) any later version.
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    This program is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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    GNU General Public License for more details.
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    You should have received a copy of the GNU General Public License
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    along with this program; if not, write to the Free Software
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    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#define DEBUG
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/ioport.h>
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#include <linux/init.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-bit.h>
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#include <asm/io.h>
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/* Power management registers */
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#define PM_CFG_REVID    0x08    /* silicon revision code */
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#define PM_CFG_IOBASE0  0x20
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#define PM_CFG_IOBASE1  0x48
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#define I2C_DIR         (pm_io_base+0x40)
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#define I2C_OUT         (pm_io_base+0x42)
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#define I2C_IN          (pm_io_base+0x44)
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#define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
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#define I2C_SDA         0x04
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/* io-region reservation */
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#define IOSPACE         0x06
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#define IOTEXT          "via-i2c"
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static u16 pm_io_base = 0;
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/*
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   It does not appear from the datasheet that the GPIO pins are
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   open drain. So a we set a low value by setting the direction to
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   output and a high value by setting the direction to input and
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   relying on the required I2C pullup. The data value is initialized
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   to 0 in via_init() and never changed.
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*/
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static void bit_via_setscl(void *data, int state)
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{
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        outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
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}
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static void bit_via_setsda(void *data, int state)
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{
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        outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
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}
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static int bit_via_getscl(void *data)
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{
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        return (0 != (inb(I2C_IN) & I2C_SCL));
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}
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static int bit_via_getsda(void *data)
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{
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        return (0 != (inb(I2C_IN) & I2C_SDA));
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}
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static struct i2c_algo_bit_data bit_data = {
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        .setsda         = bit_via_setsda,
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        .setscl         = bit_via_setscl,
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        .getsda         = bit_via_getsda,
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        .getscl         = bit_via_getscl,
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        .udelay         = 5,
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        .mdelay         = 5,
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        .timeout        = HZ
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};
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static struct i2c_adapter vt586b_adapter = {
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        .owner          = THIS_MODULE,
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        .name           = "VIA i2c",
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        .algo_data      = &bit_data,
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};
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static struct pci_device_id vt586b_ids[] __devinitdata = {
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        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
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        { 0, }
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};
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static int __devinit vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
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{
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        u16 base;
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        u8 rev;
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        int res;
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        if (pm_io_base) {
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                dev_err(&dev->dev, "i2c-via: Will only support one host\n");
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                return -ENODEV;
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        }
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        pci_read_config_byte(dev, PM_CFG_REVID, &rev);
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        switch (rev) {
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        case 0x00:
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                base = PM_CFG_IOBASE0;
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                break;
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        case 0x01:
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        case 0x10:
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                base = PM_CFG_IOBASE1;
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                break;
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        default:
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                base = PM_CFG_IOBASE1;
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                /* later revision */
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        }
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        pci_read_config_word(dev, base, &pm_io_base);
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        pm_io_base &= (0xff << 8);
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        if (!request_region(I2C_DIR, IOSPACE, IOTEXT)) {
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                dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
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                return -ENODEV;
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        }
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        outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
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        outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
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        /* set up the driverfs linkage to our parent device */
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        vt586b_adapter.dev.parent = &dev->dev;
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        res = i2c_bit_add_bus(&vt586b_adapter);
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        if ( res < 0 ) {
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                release_region(I2C_DIR, IOSPACE);
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                pm_io_base = 0;
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                return res;
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        }
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        return 0;
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}
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static void __devexit vt586b_remove(struct pci_dev *dev)
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{
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        i2c_bit_del_bus(&vt586b_adapter);
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        release_region(I2C_DIR, IOSPACE);
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        pm_io_base = 0;
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}
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static struct pci_driver vt586b_driver = {
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        .name           = "vt586b smbus",
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        .id_table       = vt586b_ids,
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        .probe          = vt586b_probe,
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        .remove         = __devexit_p(vt586b_remove),
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};
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static int __init i2c_vt586b_init(void)
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{
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        return pci_module_init(&vt586b_driver);
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}
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static void __exit i2c_vt586b_exit(void)
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{
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        pci_unregister_driver(&vt586b_driver);
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}
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MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
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MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
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MODULE_LICENSE("GPL");
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module_init(i2c_vt586b_init);
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module_exit(i2c_vt586b_exit);