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
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/pci.h>
  20#include <linux/ioport.h>
  21#include <linux/i2c.h>
  22#include <linux/i2c-algo-bit.h>
  23#include <linux/io.h>
  24
  25/* Power management registers */
  26#define PM_CFG_REVID    0x08    /* silicon revision code */
  27#define PM_CFG_IOBASE0  0x20
  28#define PM_CFG_IOBASE1  0x48
  29
  30#define I2C_DIR         (pm_io_base+0x40)
  31#define I2C_OUT         (pm_io_base+0x42)
  32#define I2C_IN          (pm_io_base+0x44)
  33#define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
  34#define I2C_SDA         0x04
  35
  36/* io-region reservation */
  37#define IOSPACE         0x06
  38
  39static struct pci_driver vt586b_driver;
  40static u16 pm_io_base;
  41
  42/*
  43   It does not appear from the datasheet that the GPIO pins are
  44   open drain. So a we set a low value by setting the direction to
  45   output and a high value by setting the direction to input and
  46   relying on the required I2C pullup. The data value is initialized
  47   to 0 in via_init() and never changed.
  48*/
  49static void bit_via_setscl(void *data, int state)
  50{
  51        outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
  52}
  53
  54static void bit_via_setsda(void *data, int state)
  55{
  56        outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
  57}
  58
  59static int bit_via_getscl(void *data)
  60{
  61        return (0 != (inb(I2C_IN) & I2C_SCL));
  62}
  63
  64static int bit_via_getsda(void *data)
  65{
  66        return (0 != (inb(I2C_IN) & I2C_SDA));
  67}
  68
  69
  70static struct i2c_algo_bit_data bit_data = {
  71        .setsda         = bit_via_setsda,
  72        .setscl         = bit_via_setscl,
  73        .getsda         = bit_via_getsda,
  74        .getscl         = bit_via_getscl,
  75        .udelay         = 5,
  76        .timeout        = HZ
  77};
  78
  79static struct i2c_adapter vt586b_adapter = {
  80        .owner          = THIS_MODULE,
  81        .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
  82        .name           = "VIA i2c",
  83        .algo_data      = &bit_data,
  84};
  85
  86
  87static const struct pci_device_id vt586b_ids[] = {
  88        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  89        { 0, }
  90};
  91
  92MODULE_DEVICE_TABLE (pci, vt586b_ids);
  93
  94static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
  95{
  96        u16 base;
  97        u8 rev;
  98        int res;
  99
 100        if (pm_io_base) {
 101                dev_err(&dev->dev, "i2c-via: Will only support one host\n");
 102                return -ENODEV;
 103        }
 104
 105        pci_read_config_byte(dev, PM_CFG_REVID, &rev);
 106
 107        switch (rev) {
 108        case 0x00:
 109                base = PM_CFG_IOBASE0;
 110                break;
 111        case 0x01:
 112        case 0x10:
 113                base = PM_CFG_IOBASE1;
 114                break;
 115
 116        default:
 117                base = PM_CFG_IOBASE1;
 118                /* later revision */
 119        }
 120
 121        pci_read_config_word(dev, base, &pm_io_base);
 122        pm_io_base &= (0xff << 8);
 123
 124        if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
 125                dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
 126                return -ENODEV;
 127        }
 128
 129        outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
 130        outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
 131
 132        /* set up the sysfs linkage to our parent device */
 133        vt586b_adapter.dev.parent = &dev->dev;
 134
 135        res = i2c_bit_add_bus(&vt586b_adapter);
 136        if ( res < 0 ) {
 137                release_region(I2C_DIR, IOSPACE);
 138                pm_io_base = 0;
 139                return res;
 140        }
 141        return 0;
 142}
 143
 144static void vt586b_remove(struct pci_dev *dev)
 145{
 146        i2c_del_adapter(&vt586b_adapter);
 147        release_region(I2C_DIR, IOSPACE);
 148        pm_io_base = 0;
 149}
 150
 151
 152static struct pci_driver vt586b_driver = {
 153        .name           = "vt586b_smbus",
 154        .id_table       = vt586b_ids,
 155        .probe          = vt586b_probe,
 156        .remove         = vt586b_remove,
 157};
 158
 159module_pci_driver(vt586b_driver);
 160
 161MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
 162MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
 163MODULE_LICENSE("GPL");
 164