aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-via.c
blob: be662511c58bf931aef8e57de31905d710952363 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/*
    i2c Support for Via Technologies 82C586B South Bridge

    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/io.h>

/* Power management registers */
#define PM_CFG_REVID	0x08	/* silicon revision code */
#define PM_CFG_IOBASE0	0x20
#define PM_CFG_IOBASE1	0x48

#define I2C_DIR		(pm_io_base+0x40)
#define I2C_OUT		(pm_io_base+0x42)
#define I2C_IN		(pm_io_base+0x44)
#define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
#define I2C_SDA		0x04

/* io-region reservation */
#define IOSPACE		0x06

static struct pci_driver vt586b_driver;
static u16 pm_io_base;

/*
   It does not appear from the datasheet that the GPIO pins are
   open drain. So a we set a low value by setting the direction to
   output and a high value by setting the direction to input and
   relying on the required I2C pullup. The data value is initialized
   to 0 in via_init() and never changed.
*/
static void bit_via_setscl(void *data, int state)
{
	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
}

static void bit_via_setsda(void *data, int state)
{
	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
}

static int bit_via_getscl(void *data)
{
	return (0 != (inb(I2C_IN) & I2C_SCL));
}

static int bit_via_getsda(void *data)
{
	return (0 != (inb(I2C_IN) & I2C_SDA));
}


static struct i2c_algo_bit_data bit_data = {
	.setsda		= bit_via_setsda,
	.setscl		= bit_via_setscl,
	.getsda		= bit_via_getsda,
	.getscl		= bit_via_getscl,
	.udelay		= 5,
	.timeout	= HZ
};

static struct i2c_adapter vt586b_adapter = {
	.owner		= THIS_MODULE,
	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
	.name		= "VIA i2c",
	.algo_data	= &bit_data,
};


static DEFINE_PCI_DEVICE_TABLE(vt586b_ids) = {
	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
	{ 0, }
};

MODULE_DEVICE_TABLE (pci, vt586b_ids);

static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
	u16 base;
	u8 rev;
	int res;

	if (pm_io_base) {
		dev_err(&dev->dev, "i2c-via: Will only support one host\n");
		return -ENODEV;
	}

	pci_read_config_byte(dev, PM_CFG_REVID, &rev);

	switch (rev) {
	case 0x00:
		base = PM_CFG_IOBASE0;
		break;
	case 0x01:
	case 0x10:
		base = PM_CFG_IOBASE1;
		break;

	default:
		base = PM_CFG_IOBASE1;
		/* later revision */
	}

	pci_read_config_word(dev, base, &pm_io_base);
	pm_io_base &= (0xff << 8);

	if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
		dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
		return -ENODEV;
	}

	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);

	/* set up the sysfs linkage to our parent device */
	vt586b_adapter.dev.parent = &dev->dev;

	res = i2c_bit_add_bus(&vt586b_adapter);
	if ( res < 0 ) {
		release_region(I2C_DIR, IOSPACE);
		pm_io_base = 0;
		return res;
	}
	return 0;
}

static void vt586b_remove(struct pci_dev *dev)
{
	i2c_del_adapter(&vt586b_adapter);
	release_region(I2C_DIR, IOSPACE);
	pm_io_base = 0;
}


static struct pci_driver vt586b_driver = {
	.name		= "vt586b_smbus",
	.id_table	= vt586b_ids,
	.probe		= vt586b_probe,
	.remove		= vt586b_remove,
};

module_pci_driver(vt586b_driver);

MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
MODULE_LICENSE("GPL");