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
42struct 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 */
67static __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
78static __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
85static 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
100static 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
110static 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
116static 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
173err_out_free_device:
174	if (dev->virt_addr)
175		iounmap(dev->virt_addr);
176	kfree(dev);
177
178	return err;
179}
180
181static 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
192static struct pci_device_id matrox_w1_tbl[] = {
193	{ PCI_DEVICE(PCI_VENDOR_ID_MATROX, PCI_DEVICE_ID_MATROX_G400) },
194	{ },
195};
196MODULE_DEVICE_TABLE(pci, matrox_w1_tbl);
197
198static 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};
204module_pci_driver(matrox_w1_pci_driver);
205
206MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
207MODULE_DESCRIPTION("Driver for transport(Dallas 1-wire protocol) over VGA DDC(matrox gpio).");
208MODULE_LICENSE("GPL");
209