1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * matrox_w1.c
4 *
5 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
6 */
7
8 #include <asm/types.h>
9 #include <linux/atomic.h>
10 #include <linux/io.h>
11
12 #include <linux/delay.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/list.h>
16 #include <linux/interrupt.h>
17 #include <linux/spinlock.h>
18 #include <linux/timer.h>
19 #include <linux/slab.h>
20 #include <linux/pci_ids.h>
21 #include <linux/pci.h>
22
23 #include <linux/w1.h>
24
25 /*
26 * Matrox G400 DDC registers.
27 */
28
29 #define MATROX_G400_DDC_CLK (1<<4)
30 #define MATROX_G400_DDC_DATA (1<<1)
31
32 #define MATROX_BASE 0x3C00
33 #define MATROX_STATUS 0x1e14
34
35 #define MATROX_PORT_INDEX_OFFSET 0x00
36 #define MATROX_PORT_DATA_OFFSET 0x0A
37
38 #define MATROX_GET_CONTROL 0x2A
39 #define MATROX_GET_DATA 0x2B
40 #define MATROX_CURSOR_CTL 0x06
41
42 struct matrox_device {
43 void __iomem *base_addr;
44 void __iomem *port_index;
45 void __iomem *port_data;
46 u8 data_mask;
47
48 unsigned long phys_addr;
49 void __iomem *virt_addr;
50 unsigned long found;
51
52 struct w1_bus_master *bus_master;
53 };
54
55 /*
56 * These functions read and write DDC Data bit.
57 *
58 * Using tristate pins, since i can't find any open-drain pin in whole motherboard.
59 * Unfortunately we can't connect to Intel's 82801xx IO controller
60 * since we don't know motherboard schema, which has pretty unused(may be not) GPIO.
61 *
62 * I've heard that PIIX also has open drain pin.
63 *
64 * Port mapping.
65 */
matrox_w1_read_reg(struct matrox_device * dev,u8 reg)66 static inline u8 matrox_w1_read_reg(struct matrox_device *dev, u8 reg)
67 {
68 u8 ret;
69
70 writeb(reg, dev->port_index);
71 ret = readb(dev->port_data);
72 barrier();
73
74 return ret;
75 }
76
matrox_w1_write_reg(struct matrox_device * dev,u8 reg,u8 val)77 static inline void matrox_w1_write_reg(struct matrox_device *dev, u8 reg, u8 val)
78 {
79 writeb(reg, dev->port_index);
80 writeb(val, dev->port_data);
81 wmb();
82 }
83
matrox_w1_write_ddc_bit(void * data,u8 bit)84 static void matrox_w1_write_ddc_bit(void *data, u8 bit)
85 {
86 u8 ret;
87 struct matrox_device *dev = data;
88
89 if (bit)
90 bit = 0;
91 else
92 bit = dev->data_mask;
93
94 ret = matrox_w1_read_reg(dev, MATROX_GET_CONTROL);
95 matrox_w1_write_reg(dev, MATROX_GET_CONTROL, ((ret & ~dev->data_mask) | bit));
96 matrox_w1_write_reg(dev, MATROX_GET_DATA, 0x00);
97 }
98
matrox_w1_read_ddc_bit(void * data)99 static u8 matrox_w1_read_ddc_bit(void *data)
100 {
101 u8 ret;
102 struct matrox_device *dev = data;
103
104 ret = matrox_w1_read_reg(dev, MATROX_GET_DATA);
105
106 return ret;
107 }
108
matrox_w1_hw_init(struct matrox_device * dev)109 static void matrox_w1_hw_init(struct matrox_device *dev)
110 {
111 matrox_w1_write_reg(dev, MATROX_GET_DATA, 0xFF);
112 matrox_w1_write_reg(dev, MATROX_GET_CONTROL, 0x00);
113 }
114
matrox_w1_probe(struct pci_dev * pdev,const struct pci_device_id * ent)115 static int matrox_w1_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
116 {
117 struct matrox_device *dev;
118 int err;
119
120 if (pdev->vendor != PCI_VENDOR_ID_MATROX || pdev->device != PCI_DEVICE_ID_MATROX_G400)
121 return -ENODEV;
122
123 dev = kzalloc(sizeof(struct matrox_device) +
124 sizeof(struct w1_bus_master), GFP_KERNEL);
125 if (!dev)
126 return -ENOMEM;
127
128 dev->bus_master = (struct w1_bus_master *)(dev + 1);
129
130 /*
131 * True for G400, for some other we need resource 0, see drivers/video/matrox/matroxfb_base.c
132 */
133
134 dev->phys_addr = pci_resource_start(pdev, 1);
135
136 dev->virt_addr = ioremap(dev->phys_addr, 16384);
137 if (!dev->virt_addr) {
138 dev_err(&pdev->dev, "%s: failed to ioremap(0x%lx, %d).\n",
139 __func__, dev->phys_addr, 16384);
140 err = -EIO;
141 goto err_out_free_device;
142 }
143
144 dev->base_addr = dev->virt_addr + MATROX_BASE;
145 dev->port_index = dev->base_addr + MATROX_PORT_INDEX_OFFSET;
146 dev->port_data = dev->base_addr + MATROX_PORT_DATA_OFFSET;
147 dev->data_mask = (MATROX_G400_DDC_DATA);
148
149 matrox_w1_hw_init(dev);
150
151 dev->bus_master->data = dev;
152 dev->bus_master->read_bit = &matrox_w1_read_ddc_bit;
153 dev->bus_master->write_bit = &matrox_w1_write_ddc_bit;
154
155 err = w1_add_master_device(dev->bus_master);
156 if (err)
157 goto err_out_free_device;
158
159 pci_set_drvdata(pdev, dev);
160
161 dev->found = 1;
162
163 dev_info(&pdev->dev, "Matrox G400 GPIO transport layer for 1-wire.\n");
164
165 return 0;
166
167 err_out_free_device:
168 if (dev->virt_addr)
169 iounmap(dev->virt_addr);
170 kfree(dev);
171
172 return err;
173 }
174
matrox_w1_remove(struct pci_dev * pdev)175 static void matrox_w1_remove(struct pci_dev *pdev)
176 {
177 struct matrox_device *dev = pci_get_drvdata(pdev);
178
179 if (dev->found) {
180 w1_remove_master_device(dev->bus_master);
181 iounmap(dev->virt_addr);
182 }
183 kfree(dev);
184 }
185
186 static struct pci_device_id matrox_w1_tbl[] = {
187 { PCI_DEVICE(PCI_VENDOR_ID_MATROX, PCI_DEVICE_ID_MATROX_G400) },
188 { },
189 };
190 MODULE_DEVICE_TABLE(pci, matrox_w1_tbl);
191
192 static struct pci_driver matrox_w1_pci_driver = {
193 .name = "matrox_w1",
194 .id_table = matrox_w1_tbl,
195 .probe = matrox_w1_probe,
196 .remove = matrox_w1_remove,
197 };
198 module_pci_driver(matrox_w1_pci_driver);
199
200 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
201 MODULE_DESCRIPTION("Driver for transport(Dallas 1-wire protocol) over VGA DDC(matrox gpio).");
202 MODULE_LICENSE("GPL");
203