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
31 static struct pci_driver vt586b_driver;
32 static 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 */
bit_via_setscl(void * data,int state)41 static 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
bit_via_setsda(void * data,int state)46 static 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
bit_via_getscl(void * data)51 static int bit_via_getscl(void *data)
52 {
53 return (0 != (inb(I2C_IN) & I2C_SCL));
54 }
55
bit_via_getsda(void * data)56 static int bit_via_getsda(void *data)
57 {
58 return (0 != (inb(I2C_IN) & I2C_SDA));
59 }
60
61
62 static 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
71 static struct i2c_adapter vt586b_adapter = {
72 .owner = THIS_MODULE,
73 .class = I2C_CLASS_HWMON,
74 .name = "VIA i2c",
75 .algo_data = &bit_data,
76 };
77
78
79 static const struct pci_device_id vt586b_ids[] = {
80 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
81 { 0, }
82 };
83
84 MODULE_DEVICE_TABLE (pci, vt586b_ids);
85
vt586b_probe(struct pci_dev * dev,const struct pci_device_id * id)86 static 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 return dev_err_probe(&dev->dev, -ENODEV,
94 "Will only support one host\n");
95
96 pci_read_config_byte(dev, PM_CFG_REVID, &rev);
97
98 switch (rev) {
99 case 0x00:
100 base = PM_CFG_IOBASE0;
101 break;
102 case 0x01:
103 case 0x10:
104 base = PM_CFG_IOBASE1;
105 break;
106
107 default:
108 base = PM_CFG_IOBASE1;
109 /* later revision */
110 }
111
112 pci_read_config_word(dev, base, &pm_io_base);
113 pm_io_base &= (0xff << 8);
114
115 if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name))
116 return dev_err_probe(&dev->dev, -ENODEV,
117 "IO 0x%x-0x%x already in use\n",
118 I2C_DIR, I2C_DIR + IOSPACE);
119
120 outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
121 outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
122
123 /* set up the sysfs linkage to our parent device */
124 vt586b_adapter.dev.parent = &dev->dev;
125
126 res = i2c_bit_add_bus(&vt586b_adapter);
127 if ( res < 0 ) {
128 release_region(I2C_DIR, IOSPACE);
129 pm_io_base = 0;
130 return res;
131 }
132 return 0;
133 }
134
vt586b_remove(struct pci_dev * dev)135 static void vt586b_remove(struct pci_dev *dev)
136 {
137 i2c_del_adapter(&vt586b_adapter);
138 release_region(I2C_DIR, IOSPACE);
139 pm_io_base = 0;
140 }
141
142
143 static struct pci_driver vt586b_driver = {
144 .name = "vt586b_smbus",
145 .id_table = vt586b_ids,
146 .probe = vt586b_probe,
147 .remove = vt586b_remove,
148 };
149
150 module_pci_driver(vt586b_driver);
151
152 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
153 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
154 MODULE_LICENSE("GPL");
155