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
42struct 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 */
66static 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
77static 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
84static 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
99static 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
109static 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
115static 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
167err_out_free_device:
168	if (dev->virt_addr)
169		iounmap(dev->virt_addr);
170	kfree(dev);
171
172	return err;
173}
174
175static 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
186static struct pci_device_id matrox_w1_tbl[] = {
187	{ PCI_DEVICE(PCI_VENDOR_ID_MATROX, PCI_DEVICE_ID_MATROX_G400) },
188	{ },
189};
190MODULE_DEVICE_TABLE(pci, matrox_w1_tbl);
191
192static 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};
198module_pci_driver(matrox_w1_pci_driver);
199
200MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
201MODULE_DESCRIPTION("Driver for transport(Dallas 1-wire protocol) over VGA DDC(matrox gpio).");
202MODULE_LICENSE("GPL");
203