LXR linux/drivers/i2c/busses/i2c-via.c

   1/*
   2    i2c Support for Via Technologies 82C586B South Bridge
   3
   4    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19*/
  20
  21#include <linux/kernel.h>
  22#include <linux/module.h>
  23#include <linux/pci.h>
  24#include <linux/ioport.h>
  25#include <linux/init.h>
  26#include <linux/i2c.h>
  27#include <linux/i2c-algo-bit.h>
  28#include <linux/io.h>
  29
  30/* Power management registers */
  31#define PM_CFG_REVID    0x08    /* silicon revision code */
  32#define PM_CFG_IOBASE0  0x20
  33#define PM_CFG_IOBASE1  0x48
  34
  35#define I2C_DIR         (pm_io_base+0x40)
  36#define I2C_OUT         (pm_io_base+0x42)
  37#define I2C_IN          (pm_io_base+0x44)
  38#define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
  39#define I2C_SDA         0x04
  40
  41/* io-region reservation */
  42#define IOSPACE         0x06
  43
  44static struct pci_driver vt586b_driver;
  45static u16 pm_io_base;
  46
  47/*
  48   It does not appear from the datasheet that the GPIO pins are
  49   open drain. So a we set a low value by setting the direction to
  50   output and a high value by setting the direction to input and
  51   relying on the required I2C pullup. The data value is initialized
  52   to 0 in via_init() and never changed.
  53*/
  54static void bit_via_setscl(void *data, int state)
  55{
  56        outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
  57}
  58
  59static void bit_via_setsda(void *data, int state)
  60{
  61        outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
  62}
  63
  64static int bit_via_getscl(void *data)
  65{
  66        return (0 != (inb(I2C_IN) & I2C_SCL));
  67}
  68
  69static int bit_via_getsda(void *data)
  70{
  71        return (0 != (inb(I2C_IN) & I2C_SDA));
  72}
  73
  74
  75static struct i2c_algo_bit_data bit_data = {
  76        .setsda         = bit_via_setsda,
  77        .setscl         = bit_via_setscl,
  78        .getsda         = bit_via_getsda,
  79        .getscl         = bit_via_getscl,
  80        .udelay         = 5,
  81        .timeout        = HZ
  82};
  83
  84static struct i2c_adapter vt586b_adapter = {
  85        .owner          = THIS_MODULE,
  86        .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
  87        .name           = "VIA i2c",
  88        .algo_data      = &bit_data,
  89};
  90
  91
  92static DEFINE_PCI_DEVICE_TABLE(vt586b_ids) = {
  93        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  94        { 0, }
  95};
  96
  97MODULE_DEVICE_TABLE (pci, vt586b_ids);
  98
  99static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
 100{
 101        u16 base;
 102        u8 rev;
 103        int res;
 104
 105        if (pm_io_base) {
 106                dev_err(&dev->dev, "i2c-via: Will only support one host\n");
 107                return -ENODEV;
 108        }
 109
 110        pci_read_config_byte(dev, PM_CFG_REVID, &rev);
 111
 112        switch (rev) {
 113        case 0x00:
 114                base = PM_CFG_IOBASE0;
 115                break;
 116        case 0x01:
 117        case 0x10:
 118                base = PM_CFG_IOBASE1;
 119                break;
 120
 121        default:
 122                base = PM_CFG_IOBASE1;
 123                /* later revision */
 124        }
 125
 126        pci_read_config_word(dev, base, &pm_io_base);
 127        pm_io_base &= (0xff << 8);
 128
 129        if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
 130                dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
 131                return -ENODEV;
 132        }
 133
 134        outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
 135        outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
 136
 137        /* set up the sysfs linkage to our parent device */
 138        vt586b_adapter.dev.parent = &dev->dev;
 139
 140        res = i2c_bit_add_bus(&vt586b_adapter);
 141        if ( res < 0 ) {
 142                release_region(I2C_DIR, IOSPACE);
 143                pm_io_base = 0;
 144                return res;
 145        }
 146        return 0;
 147}
 148
 149static void vt586b_remove(struct pci_dev *dev)
 150{
 151        i2c_del_adapter(&vt586b_adapter);
 152        release_region(I2C_DIR, IOSPACE);
 153        pm_io_base = 0;
 154}
 155
 156
 157static struct pci_driver vt586b_driver = {
 158        .name           = "vt586b_smbus",
 159        .id_table       = vt586b_ids,
 160        .probe          = vt586b_probe,
 161        .remove         = vt586b_remove,
 162};
 163
 164module_pci_driver(vt586b_driver);
 165
 166MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
 167MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
 168MODULE_LICENSE("GPL");
 169