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