drivers/i2c/busses/i2c-via.c

   1 /*
   2     i2c-via.c - Part of lm_sensors,  Linux kernel modules
   3                 for hardware monitoring
   4
   5     i2c Support for Via Technologies 82C586B South Bridge
   6
   7     Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17     GNU General Public License for more details.
  18
  19     You should have received a copy of the GNU General Public License
  20     along with this program; if not, write to the Free Software
  21     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include <linux/config.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/pci.h>
  28 #include <linux/ioport.h>
  29 #include <linux/init.h>
  30 #include <linux/i2c.h>
  31 #include <linux/i2c-algo-bit.h>
  32 #include <asm/io.h>
  33
  34 /* Power management registers */
  35 #define PM_CFG_REVID    0x08    /* silicon revision code */
  36 #define PM_CFG_IOBASE0  0x20
  37 #define PM_CFG_IOBASE1  0x48
  38
  39 #define I2C_DIR         (pm_io_base+0x40)
  40 #define I2C_OUT         (pm_io_base+0x42)
  41 #define I2C_IN          (pm_io_base+0x44)
  42 #define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
  43 #define I2C_SDA         0x04
  44
  45 /* io-region reservation */
  46 #define IOSPACE         0x06
  47 #define IOTEXT          "via-i2c"
  48
  49 static u16 pm_io_base = 0;
  50
  51 /*
  52    It does not appear from the datasheet that the GPIO pins are
  53    open drain. So a we set a low value by setting the direction to
  54    output and a high value by setting the direction to input and
  55    relying on the required I2C pullup. The data value is initialized
  56    to 0 in via_init() and never changed.
  57 */
  58 static void bit_via_setscl(void *data, int state)
  59 {
  60         outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
  61 }
  62
  63 static void bit_via_setsda(void *data, int state)
  64 {
  65         outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
  66 }
  67
  68 static int bit_via_getscl(void *data)
  69 {
  70         return (0 != (inb(I2C_IN) & I2C_SCL));
  71 }
  72
  73 static int bit_via_getsda(void *data)
  74 {
  75         return (0 != (inb(I2C_IN) & I2C_SDA));
  76 }
  77
  78
  79 static struct i2c_algo_bit_data bit_data = {
  80         .setsda         = bit_via_setsda,
  81         .setscl         = bit_via_setscl,
  82         .getsda         = bit_via_getsda,
  83         .getscl         = bit_via_getscl,
  84         .udelay         = 5,
  85         .mdelay         = 5,
  86         .timeout        = HZ
  87 };
  88
  89 static struct i2c_adapter vt586b_adapter = {
  90         .owner          = THIS_MODULE,
  91         .class          = I2C_CLASS_HWMON,
  92         .name           = "VIA i2c",
  93         .algo_data      = &bit_data,
  94 };
  95
  96
  97 static struct pci_device_id vt586b_ids[] __devinitdata = {
  98         { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  99         { 0, }
 100 };
 101
 102 MODULE_DEVICE_TABLE (pci, vt586b_ids);
 103
 104 static int __devinit vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
 105 {
 106         u16 base;
 107         u8 rev;
 108         int res;
 109
 110         if (pm_io_base) {
 111                 dev_err(&dev->dev, "i2c-via: Will only support one host\n");
 112                 return -ENODEV;
 113         }
 114
 115         pci_read_config_byte(dev, PM_CFG_REVID, &rev);
 116
 117         switch (rev) {
 118         case 0x00:
 119                 base = PM_CFG_IOBASE0;
 120                 break;
 121         case 0x01:
 122         case 0x10:
 123                 base = PM_CFG_IOBASE1;
 124                 break;
 125
 126         default:
 127                 base = PM_CFG_IOBASE1;
 128                 /* later revision */
 129         }
 130
 131         pci_read_config_word(dev, base, &pm_io_base);
 132         pm_io_base &= (0xff << 8);
 133
 134         if (!request_region(I2C_DIR, IOSPACE, IOTEXT)) {
 135                 dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
 136                 return -ENODEV;
 137         }
 138
 139         outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
 140         outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
 141
 142         /* set up the driverfs linkage to our parent device */
 143         vt586b_adapter.dev.parent = &dev->dev;
 144
 145         res = i2c_bit_add_bus(&vt586b_adapter);
 146         if ( res < 0 ) {
 147                 release_region(I2C_DIR, IOSPACE);
 148                 pm_io_base = 0;
 149                 return res;
 150         }
 151         return 0;
 152 }
 153
 154 static void __devexit vt586b_remove(struct pci_dev *dev)
 155 {
 156         i2c_bit_del_bus(&vt586b_adapter);
 157         release_region(I2C_DIR, IOSPACE);
 158         pm_io_base = 0;
 159 }
 160
 161
 162 static struct pci_driver vt586b_driver = {
 163         .name           = "vt586b_smbus",
 164         .id_table       = vt586b_ids,
 165         .probe          = vt586b_probe,
 166         .remove         = __devexit_p(vt586b_remove),
 167 };
 168
 169 static int __init i2c_vt586b_init(void)
 170 {
 171         return pci_register_driver(&vt586b_driver);
 172 }
 173
 174 static void __exit i2c_vt586b_exit(void)
 175 {
 176         pci_unregister_driver(&vt586b_driver);
 177 }
 178
 179
 180 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
 181 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
 182 MODULE_LICENSE("GPL");
 183
 184 module_init(i2c_vt586b_init);
 185 module_exit(i2c_vt586b_exit);