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/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/pci.h>
  27 #include <linux/ioport.h>
  28 #include <linux/init.h>
  29 #include <linux/i2c.h>
  30 #include <linux/i2c-algo-bit.h>
  31 #include <asm/io.h>
  32
  33 /* Power management registers */
  34 #define PM_CFG_REVID    0x08    /* silicon revision code */
  35 #define PM_CFG_IOBASE0  0x20
  36 #define PM_CFG_IOBASE1  0x48
  37
  38 #define I2C_DIR         (pm_io_base+0x40)
  39 #define I2C_OUT         (pm_io_base+0x42)
  40 #define I2C_IN          (pm_io_base+0x44)
  41 #define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
  42 #define I2C_SDA         0x04
  43
  44 /* io-region reservation */
  45 #define IOSPACE         0x06
  46
  47 static struct pci_driver vt586b_driver;
  48 static u16 pm_io_base;
  49
  50 /*
  51    It does not appear from the datasheet that the GPIO pins are
  52    open drain. So a we set a low value by setting the direction to
  53    output and a high value by setting the direction to input and
  54    relying on the required I2C pullup. The data value is initialized
  55    to 0 in via_init() and never changed.
  56 */
  57 static void bit_via_setscl(void *data, int state)
  58 {
  59         outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
  60 }
  61
  62 static void bit_via_setsda(void *data, int state)
  63 {
  64         outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
  65 }
  66
  67 static int bit_via_getscl(void *data)
  68 {
  69         return (0 != (inb(I2C_IN) & I2C_SCL));
  70 }
  71
  72 static int bit_via_getsda(void *data)
  73 {
  74         return (0 != (inb(I2C_IN) & I2C_SDA));
  75 }
  76
  77
  78 static struct i2c_algo_bit_data bit_data = {
  79         .setsda         = bit_via_setsda,
  80         .setscl         = bit_via_setscl,
  81         .getsda         = bit_via_getsda,
  82         .getscl         = bit_via_getscl,
  83         .udelay         = 5,
  84         .timeout        = HZ
  85 };
  86
  87 static struct i2c_adapter vt586b_adapter = {
  88         .owner          = THIS_MODULE,
  89         .class          = I2C_CLASS_HWMON,
  90         .name           = "VIA i2c",
  91         .algo_data      = &bit_data,
  92 };
  93
  94
  95 static struct pci_device_id vt586b_ids[] __devinitdata = {
  96         { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  97         { 0, }
  98 };
  99
 100 MODULE_DEVICE_TABLE (pci, vt586b_ids);
 101
 102 static int __devinit vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
 103 {
 104         u16 base;
 105         u8 rev;
 106         int res;
 107
 108         if (pm_io_base) {
 109                 dev_err(&dev->dev, "i2c-via: Will only support one host\n");
 110                 return -ENODEV;
 111         }
 112
 113         pci_read_config_byte(dev, PM_CFG_REVID, &rev);
 114
 115         switch (rev) {
 116         case 0x00:
 117                 base = PM_CFG_IOBASE0;
 118                 break;
 119         case 0x01:
 120         case 0x10:
 121                 base = PM_CFG_IOBASE1;
 122                 break;
 123
 124         default:
 125                 base = PM_CFG_IOBASE1;
 126                 /* later revision */
 127         }
 128
 129         pci_read_config_word(dev, base, &pm_io_base);
 130         pm_io_base &= (0xff << 8);
 131
 132         if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
 133                 dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
 134                 return -ENODEV;
 135         }
 136
 137         outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
 138         outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
 139
 140         /* set up the driverfs linkage to our parent device */
 141         vt586b_adapter.dev.parent = &dev->dev;
 142
 143         res = i2c_bit_add_bus(&vt586b_adapter);
 144         if ( res < 0 ) {
 145                 release_region(I2C_DIR, IOSPACE);
 146                 pm_io_base = 0;
 147                 return res;
 148         }
 149         return 0;
 150 }
 151
 152 static void __devexit vt586b_remove(struct pci_dev *dev)
 153 {
 154         i2c_bit_del_bus(&vt586b_adapter);
 155         release_region(I2C_DIR, IOSPACE);
 156         pm_io_base = 0;
 157 }
 158
 159
 160 static struct pci_driver vt586b_driver = {
 161         .name           = "vt586b_smbus",
 162         .id_table       = vt586b_ids,
 163         .probe          = vt586b_probe,
 164         .remove         = __devexit_p(vt586b_remove),
 165 };
 166
 167 static int __init i2c_vt586b_init(void)
 168 {
 169         return pci_register_driver(&vt586b_driver);
 170 }
 171
 172 static void __exit i2c_vt586b_exit(void)
 173 {
 174         pci_unregister_driver(&vt586b_driver);
 175 }
 176
 177
 178 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
 179 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
 180 MODULE_LICENSE("GPL");
 181
 182 module_init(i2c_vt586b_init);
 183 module_exit(i2c_vt586b_exit);