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

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3    i2c Support for Via Technologies 82C586B South Bridge
   4
   5    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
   6
   7*/
   8
   9#include <linux/kernel.h>
  10#include <linux/module.h>
  11#include <linux/pci.h>
  12#include <linux/ioport.h>
  13#include <linux/i2c.h>
  14#include <linux/i2c-algo-bit.h>
  15#include <linux/io.h>
  16
  17/* Power management registers */
  18#define PM_CFG_REVID    0x08    /* silicon revision code */
  19#define PM_CFG_IOBASE0  0x20
  20#define PM_CFG_IOBASE1  0x48
  21
  22#define I2C_DIR         (pm_io_base+0x40)
  23#define I2C_OUT         (pm_io_base+0x42)
  24#define I2C_IN          (pm_io_base+0x44)
  25#define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
  26#define I2C_SDA         0x04
  27
  28/* io-region reservation */
  29#define IOSPACE         0x06
  30
  31static struct pci_driver vt586b_driver;
  32static u16 pm_io_base;
  33
  34/*
  35   It does not appear from the datasheet that the GPIO pins are
  36   open drain. So a we set a low value by setting the direction to
  37   output and a high value by setting the direction to input and
  38   relying on the required I2C pullup. The data value is initialized
  39   to 0 in via_init() and never changed.
  40*/
  41static void bit_via_setscl(void *data, int state)
  42{
  43        outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
  44}
  45
  46static void bit_via_setsda(void *data, int state)
  47{
  48        outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
  49}
  50
  51static int bit_via_getscl(void *data)
  52{
  53        return (0 != (inb(I2C_IN) & I2C_SCL));
  54}
  55
  56static int bit_via_getsda(void *data)
  57{
  58        return (0 != (inb(I2C_IN) & I2C_SDA));
  59}
  60
  61
  62static struct i2c_algo_bit_data bit_data = {
  63        .setsda         = bit_via_setsda,
  64        .setscl         = bit_via_setscl,
  65        .getsda         = bit_via_getsda,
  66        .getscl         = bit_via_getscl,
  67        .udelay         = 5,
  68        .timeout        = HZ
  69};
  70
  71static struct i2c_adapter vt586b_adapter = {
  72        .owner          = THIS_MODULE,
  73        .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
  74        .name           = "VIA i2c",
  75        .algo_data      = &bit_data,
  76};
  77
  78
  79static const struct pci_device_id vt586b_ids[] = {
  80        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  81        { 0, }
  82};
  83
  84MODULE_DEVICE_TABLE (pci, vt586b_ids);
  85
  86static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
  87{
  88        u16 base;
  89        u8 rev;
  90        int res;
  91
  92        if (pm_io_base) {
  93                dev_err(&dev->dev, "i2c-via: Will only support one host\n");
  94                return -ENODEV;
  95        }
  96
  97        pci_read_config_byte(dev, PM_CFG_REVID, &rev);
  98
  99        switch (rev) {
 100        case 0x00:
 101                base = PM_CFG_IOBASE0;
 102                break;
 103        case 0x01:
 104        case 0x10:
 105                base = PM_CFG_IOBASE1;
 106                break;
 107
 108        default:
 109                base = PM_CFG_IOBASE1;
 110                /* later revision */
 111        }
 112
 113        pci_read_config_word(dev, base, &pm_io_base);
 114        pm_io_base &= (0xff << 8);
 115
 116        if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
 117                dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
 118                return -ENODEV;
 119        }
 120
 121        outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
 122        outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
 123
 124        /* set up the sysfs linkage to our parent device */
 125        vt586b_adapter.dev.parent = &dev->dev;
 126
 127        res = i2c_bit_add_bus(&vt586b_adapter);
 128        if ( res < 0 ) {
 129                release_region(I2C_DIR, IOSPACE);
 130                pm_io_base = 0;
 131                return res;
 132        }
 133        return 0;
 134}
 135
 136static void vt586b_remove(struct pci_dev *dev)
 137{
 138        i2c_del_adapter(&vt586b_adapter);
 139        release_region(I2C_DIR, IOSPACE);
 140        pm_io_base = 0;
 141}
 142
 143
 144static struct pci_driver vt586b_driver = {
 145        .name           = "vt586b_smbus",
 146        .id_table       = vt586b_ids,
 147        .probe          = vt586b_probe,
 148        .remove         = vt586b_remove,
 149};
 150
 151module_pci_driver(vt586b_driver);
 152
 153MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
 154MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
 155MODULE_LICENSE("GPL");
 156