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 <asm/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 {
44 	void __iomem *base_addr;
45 	void __iomem *port_index;
46 	void __iomem *port_data;
47 	u8 data_mask;
48 
49 	unsigned long phys_addr;
50 	void __iomem *virt_addr;
51 	unsigned long found;
52 
53 	struct w1_bus_master *bus_master;
54 };
55 
56 /*
57  * These functions read and write DDC Data bit.
58  *
59  * Using tristate pins, since i can't find any open-drain pin in whole motherboard.
60  * Unfortunately we can't connect to Intel's 82801xx IO controller
61  * since we don't know motherboard schema, which has pretty unused(may be not) GPIO.
62  *
63  * I've heard that PIIX also has open drain pin.
64  *
65  * Port mapping.
66  */
matrox_w1_read_reg(struct matrox_device * dev,u8 reg)67 static __inline__ u8 matrox_w1_read_reg(struct matrox_device *dev, u8 reg)
68 {
69 	u8 ret;
70 
71 	writeb(reg, dev->port_index);
72 	ret = readb(dev->port_data);
73 	barrier();
74 
75 	return ret;
76 }
77 
matrox_w1_write_reg(struct matrox_device * dev,u8 reg,u8 val)78 static __inline__ void matrox_w1_write_reg(struct matrox_device *dev, u8 reg, u8 val)
79 {
80 	writeb(reg, dev->port_index);
81 	writeb(val, dev->port_data);
82 	wmb();
83 }
84 
matrox_w1_write_ddc_bit(void * data,u8 bit)85 static void matrox_w1_write_ddc_bit(void *data, u8 bit)
86 {
87 	u8 ret;
88 	struct matrox_device *dev = data;
89 
90 	if (bit)
91 		bit = 0;
92 	else
93 		bit = dev->data_mask;
94 
95 	ret = matrox_w1_read_reg(dev, MATROX_GET_CONTROL);
96 	matrox_w1_write_reg(dev, MATROX_GET_CONTROL, ((ret & ~dev->data_mask) | bit));
97 	matrox_w1_write_reg(dev, MATROX_GET_DATA, 0x00);
98 }
99 
matrox_w1_read_ddc_bit(void * data)100 static u8 matrox_w1_read_ddc_bit(void *data)
101 {
102 	u8 ret;
103 	struct matrox_device *dev = data;
104 
105 	ret = matrox_w1_read_reg(dev, MATROX_GET_DATA);
106 
107 	return ret;
108 }
109 
matrox_w1_hw_init(struct matrox_device * dev)110 static void matrox_w1_hw_init(struct matrox_device *dev)
111 {
112 	matrox_w1_write_reg(dev, MATROX_GET_DATA, 0xFF);
113 	matrox_w1_write_reg(dev, MATROX_GET_CONTROL, 0x00);
114 }
115 
matrox_w1_probe(struct pci_dev * pdev,const struct pci_device_id * ent)116 static int matrox_w1_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
117 {
118 	struct matrox_device *dev;
119 	int err;
120 
121 	if (pdev->vendor != PCI_VENDOR_ID_MATROX || pdev->device != PCI_DEVICE_ID_MATROX_G400)
122 		return -ENODEV;
123 
124 	dev = kzalloc(sizeof(struct matrox_device) +
125 		       sizeof(struct w1_bus_master), GFP_KERNEL);
126 	if (!dev) {
127 		dev_err(&pdev->dev,
128 			"%s: Failed to create new matrox_device object.\n",
129 			__func__);
130 		return -ENOMEM;
131 	}
132 
133 
134 	dev->bus_master = (struct w1_bus_master *)(dev + 1);
135 
136 	/*
137 	 * True for G400, for some other we need resource 0, see drivers/video/matrox/matroxfb_base.c
138 	 */
139 
140 	dev->phys_addr = pci_resource_start(pdev, 1);
141 
142 	dev->virt_addr = ioremap(dev->phys_addr, 16384);
143 	if (!dev->virt_addr) {
144 		dev_err(&pdev->dev, "%s: failed to ioremap(0x%lx, %d).\n",
145 			__func__, dev->phys_addr, 16384);
146 		err = -EIO;
147 		goto err_out_free_device;
148 	}
149 
150 	dev->base_addr = dev->virt_addr + MATROX_BASE;
151 	dev->port_index = dev->base_addr + MATROX_PORT_INDEX_OFFSET;
152 	dev->port_data = dev->base_addr + MATROX_PORT_DATA_OFFSET;
153 	dev->data_mask = (MATROX_G400_DDC_DATA);
154 
155 	matrox_w1_hw_init(dev);
156 
157 	dev->bus_master->data = dev;
158 	dev->bus_master->read_bit = &matrox_w1_read_ddc_bit;
159 	dev->bus_master->write_bit = &matrox_w1_write_ddc_bit;
160 
161 	err = w1_add_master_device(dev->bus_master);
162 	if (err)
163 		goto err_out_free_device;
164 
165 	pci_set_drvdata(pdev, dev);
166 
167 	dev->found = 1;
168 
169 	dev_info(&pdev->dev, "Matrox G400 GPIO transport layer for 1-wire.\n");
170 
171 	return 0;
172 
173 err_out_free_device:
174 	if (dev->virt_addr)
175 		iounmap(dev->virt_addr);
176 	kfree(dev);
177 
178 	return err;
179 }
180 
matrox_w1_remove(struct pci_dev * pdev)181 static void matrox_w1_remove(struct pci_dev *pdev)
182 {
183 	struct matrox_device *dev = pci_get_drvdata(pdev);
184 
185 	if (dev->found) {
186 		w1_remove_master_device(dev->bus_master);
187 		iounmap(dev->virt_addr);
188 	}
189 	kfree(dev);
190 }
191 
192 static struct pci_device_id matrox_w1_tbl[] = {
193 	{ PCI_DEVICE(PCI_VENDOR_ID_MATROX, PCI_DEVICE_ID_MATROX_G400) },
194 	{ },
195 };
196 MODULE_DEVICE_TABLE(pci, matrox_w1_tbl);
197 
198 static struct pci_driver matrox_w1_pci_driver = {
199 	.name = "matrox_w1",
200 	.id_table = matrox_w1_tbl,
201 	.probe = matrox_w1_probe,
202 	.remove = matrox_w1_remove,
203 };
204 module_pci_driver(matrox_w1_pci_driver);
205 
206 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
207 MODULE_DESCRIPTION("Driver for transport(Dallas 1-wire protocol) over VGA DDC(matrox gpio).");
208 MODULE_LICENSE("GPL");
209