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 
39 static struct pci_driver vt586b_driver;
40 static 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 */
bit_via_setscl(void * data,int state)49 static 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 
bit_via_setsda(void * data,int state)54 static 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 
bit_via_getscl(void * data)59 static int bit_via_getscl(void *data)
60 {
61 	return (0 != (inb(I2C_IN) & I2C_SCL));
62 }
63 
bit_via_getsda(void * data)64 static int bit_via_getsda(void *data)
65 {
66 	return (0 != (inb(I2C_IN) & I2C_SDA));
67 }
68 
69 
70 static 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 
79 static 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 
87 static const struct pci_device_id vt586b_ids[] = {
88 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
89 	{ 0, }
90 };
91 
92 MODULE_DEVICE_TABLE (pci, vt586b_ids);
93 
vt586b_probe(struct pci_dev * dev,const struct pci_device_id * id)94 static 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 
vt586b_remove(struct pci_dev * dev)144 static 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 
152 static struct pci_driver vt586b_driver = {
153 	.name		= "vt586b_smbus",
154 	.id_table	= vt586b_ids,
155 	.probe		= vt586b_probe,
156 	.remove		= vt586b_remove,
157 };
158 
159 module_pci_driver(vt586b_driver);
160 
161 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
162 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
163 MODULE_LICENSE("GPL");
164