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
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/pci.h>
20#include <linux/ioport.h>
21#include <linux/i2c.h>
22#include <linux/i2c-algo-bit.h>
23#include <linux/io.h>
24
25/* Power management registers */
26#define PM_CFG_REVID	0x08	/* silicon revision code */
27#define PM_CFG_IOBASE0	0x20
28#define PM_CFG_IOBASE1	0x48
29
30#define I2C_DIR		(pm_io_base+0x40)
31#define I2C_OUT		(pm_io_base+0x42)
32#define I2C_IN		(pm_io_base+0x44)
33#define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
34#define I2C_SDA		0x04
35
36/* io-region reservation */
37#define IOSPACE		0x06
38
39static struct pci_driver vt586b_driver;
40static u16 pm_io_base;
41
42/*
43   It does not appear from the datasheet that the GPIO pins are
44   open drain. So a we set a low value by setting the direction to
45   output and a high value by setting the direction to input and
46   relying on the required I2C pullup. The data value is initialized
47   to 0 in via_init() and never changed.
48*/
49static void bit_via_setscl(void *data, int state)
50{
51	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
52}
53
54static void bit_via_setsda(void *data, int state)
55{
56	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
57}
58
59static int bit_via_getscl(void *data)
60{
61	return (0 != (inb(I2C_IN) & I2C_SCL));
62}
63
64static int bit_via_getsda(void *data)
65{
66	return (0 != (inb(I2C_IN) & I2C_SDA));
67}
68
69
70static struct i2c_algo_bit_data bit_data = {
71	.setsda		= bit_via_setsda,
72	.setscl		= bit_via_setscl,
73	.getsda		= bit_via_getsda,
74	.getscl		= bit_via_getscl,
75	.udelay		= 5,
76	.timeout	= HZ
77};
78
79static struct i2c_adapter vt586b_adapter = {
80	.owner		= THIS_MODULE,
81	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
82	.name		= "VIA i2c",
83	.algo_data	= &bit_data,
84};
85
86
87static const struct pci_device_id vt586b_ids[] = {
88	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
89	{ 0, }
90};
91
92MODULE_DEVICE_TABLE (pci, vt586b_ids);
93
94static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
95{
96	u16 base;
97	u8 rev;
98	int res;
99
100	if (pm_io_base) {
101		dev_err(&dev->dev, "i2c-via: Will only support one host\n");
102		return -ENODEV;
103	}
104
105	pci_read_config_byte(dev, PM_CFG_REVID, &rev);
106
107	switch (rev) {
108	case 0x00:
109		base = PM_CFG_IOBASE0;
110		break;
111	case 0x01:
112	case 0x10:
113		base = PM_CFG_IOBASE1;
114		break;
115
116	default:
117		base = PM_CFG_IOBASE1;
118		/* later revision */
119	}
120
121	pci_read_config_word(dev, base, &pm_io_base);
122	pm_io_base &= (0xff << 8);
123
124	if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
125		dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
126		return -ENODEV;
127	}
128
129	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
130	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
131
132	/* set up the sysfs linkage to our parent device */
133	vt586b_adapter.dev.parent = &dev->dev;
134
135	res = i2c_bit_add_bus(&vt586b_adapter);
136	if ( res < 0 ) {
137		release_region(I2C_DIR, IOSPACE);
138		pm_io_base = 0;
139		return res;
140	}
141	return 0;
142}
143
144static void vt586b_remove(struct pci_dev *dev)
145{
146	i2c_del_adapter(&vt586b_adapter);
147	release_region(I2C_DIR, IOSPACE);
148	pm_io_base = 0;
149}
150
151
152static struct pci_driver vt586b_driver = {
153	.name		= "vt586b_smbus",
154	.id_table	= vt586b_ids,
155	.probe		= vt586b_probe,
156	.remove		= vt586b_remove,
157};
158
159module_pci_driver(vt586b_driver);
160
161MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
162MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
163MODULE_LICENSE("GPL");
164