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 | */ |
41 | static void bit_via_setscl(void *data, int state) |
42 | { |
43 | outb(value: state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR); |
44 | } |
45 | |
46 | static void bit_via_setsda(void *data, int state) |
47 | { |
48 | outb(value: state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR); |
49 | } |
50 | |
51 | static int bit_via_getscl(void *data) |
52 | { |
53 | return (0 != (inb(I2C_IN) & I2C_SCL)); |
54 | } |
55 | |
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 | I2C_CLASS_SPD, |
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 | |
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 | 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, val: &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, where: base, val: &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 | |
136 | static void vt586b_remove(struct pci_dev *dev) |
137 | { |
138 | i2c_del_adapter(adap: &vt586b_adapter); |
139 | release_region(I2C_DIR, IOSPACE); |
140 | pm_io_base = 0; |
141 | } |
142 | |
143 | |
144 | static struct pci_driver vt586b_driver = { |
145 | .name = "vt586b_smbus" , |
146 | .id_table = vt586b_ids, |
147 | .probe = vt586b_probe, |
148 | .remove = vt586b_remove, |
149 | }; |
150 | |
151 | module_pci_driver(vt586b_driver); |
152 | |
153 | MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>" ); |
154 | MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge" ); |
155 | MODULE_LICENSE("GPL" ); |
156 | |