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i2c-via.c
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1 /*
2  i2c Support for Via Technologies 82C586B South Bridge
3 
4  Copyright (c) 1998, 1999 Kyösti Mälkki <[email protected]>
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) = {
94  { 0, }
95 };
96 
97 MODULE_DEVICE_TABLE (pci, vt586b_ids);
98 
99 static int __devinit 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 
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 ) {
143  pm_io_base = 0;
144  return res;
145  }
146  return 0;
147 }
148 
149 static void __devexit vt586b_remove(struct pci_dev *dev)
150 {
151  i2c_del_adapter(&vt586b_adapter);
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 = __devexit_p(vt586b_remove),
162 };
163 
164 module_pci_driver(vt586b_driver);
165 
166 MODULE_AUTHOR("Kyösti Mälkki <[email protected]>");
167 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
168 MODULE_LICENSE("GPL");