1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3    i2c Support for Via Technologies 82C586B South Bridge
4
5    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
6
7*/
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/pci.h>
12#include <linux/ioport.h>
13#include <linux/i2c.h>
14#include <linux/i2c-algo-bit.h>
15#include <linux/io.h>
16
17/* Power management registers */
18#define PM_CFG_REVID	0x08	/* silicon revision code */
19#define PM_CFG_IOBASE0	0x20
20#define PM_CFG_IOBASE1	0x48
21
22#define I2C_DIR		(pm_io_base+0x40)
23#define I2C_OUT		(pm_io_base+0x42)
24#define I2C_IN		(pm_io_base+0x44)
25#define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
26#define I2C_SDA		0x04
27
28/* io-region reservation */
29#define IOSPACE		0x06
30
31static struct pci_driver vt586b_driver;
32static u16 pm_io_base;
33
34/*
35   It does not appear from the datasheet that the GPIO pins are
36   open drain. So a we set a low value by setting the direction to
37   output and a high value by setting the direction to input and
38   relying on the required I2C pullup. The data value is initialized
39   to 0 in via_init() and never changed.
40*/
41static void bit_via_setscl(void *data, int state)
42{
43	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
44}
45
46static void bit_via_setsda(void *data, int state)
47{
48	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
49}
50
51static int bit_via_getscl(void *data)
52{
53	return (0 != (inb(I2C_IN) & I2C_SCL));
54}
55
56static int bit_via_getsda(void *data)
57{
58	return (0 != (inb(I2C_IN) & I2C_SDA));
59}
60
61
62static struct i2c_algo_bit_data bit_data = {
63	.setsda		= bit_via_setsda,
64	.setscl		= bit_via_setscl,
65	.getsda		= bit_via_getsda,
66	.getscl		= bit_via_getscl,
67	.udelay		= 5,
68	.timeout	= HZ
69};
70
71static struct i2c_adapter vt586b_adapter = {
72	.owner		= THIS_MODULE,
73	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
74	.name		= "VIA i2c",
75	.algo_data	= &bit_data,
76};
77
78
79static const struct pci_device_id vt586b_ids[] = {
80	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
81	{ 0, }
82};
83
84MODULE_DEVICE_TABLE (pci, vt586b_ids);
85
86static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
87{
88	u16 base;
89	u8 rev;
90	int res;
91
92	if (pm_io_base) {
93		dev_err(&dev->dev, "i2c-via: Will only support one host\n");
94		return -ENODEV;
95	}
96
97	pci_read_config_byte(dev, PM_CFG_REVID, &rev);
98
99	switch (rev) {
100	case 0x00:
101		base = PM_CFG_IOBASE0;
102		break;
103	case 0x01:
104	case 0x10:
105		base = PM_CFG_IOBASE1;
106		break;
107
108	default:
109		base = PM_CFG_IOBASE1;
110		/* later revision */
111	}
112
113	pci_read_config_word(dev, base, &pm_io_base);
114	pm_io_base &= (0xff << 8);
115
116	if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
117		dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
118		return -ENODEV;
119	}
120
121	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
122	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
123
124	/* set up the sysfs linkage to our parent device */
125	vt586b_adapter.dev.parent = &dev->dev;
126
127	res = i2c_bit_add_bus(&vt586b_adapter);
128	if ( res < 0 ) {
129		release_region(I2C_DIR, IOSPACE);
130		pm_io_base = 0;
131		return res;
132	}
133	return 0;
134}
135
136static void vt586b_remove(struct pci_dev *dev)
137{
138	i2c_del_adapter(&vt586b_adapter);
139	release_region(I2C_DIR, IOSPACE);
140	pm_io_base = 0;
141}
142
143
144static struct pci_driver vt586b_driver = {
145	.name		= "vt586b_smbus",
146	.id_table	= vt586b_ids,
147	.probe		= vt586b_probe,
148	.remove		= vt586b_remove,
149};
150
151module_pci_driver(vt586b_driver);
152
153MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
154MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
155MODULE_LICENSE("GPL");
156