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
  44 static struct pci_driver vt586b_driver;
  45 static 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 */
  54 static 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
  59 static 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
  64 static int bit_via_getscl(void *data)
  65 {
  66         return (0 != (inb(I2C_IN) & I2C_SCL));
  67 }
  68
  69 static int bit_via_getsda(void *data)
  70 {
  71         return (0 != (inb(I2C_IN) & I2C_SDA));
  72 }
  73
  74
  75 static 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
  84 static 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
  92 static DEFINE_PCI_DEVICE_TABLE(vt586b_ids) = {
  93         { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  94         { 0, }
  95 };
  96
  97 MODULE_DEVICE_TABLE (pci, vt586b_ids);
  98
  99 static 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
 149 static 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
 157 static struct pci_driver vt586b_driver = {
 158         .name           = "vt586b_smbus",
 159         .id_table       = vt586b_ids,
 160         .probe          = vt586b_probe,
 161         .remove         = vt586b_remove,
 162 };
 163
 164 module_pci_driver(vt586b_driver);
 165
 166 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
 167 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
 168 MODULE_LICENSE("GPL");