1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * tscan1.c: driver for Technologic Systems TS-CAN1 PC104 boards
4 *
5 * Copyright 2010 Andre B. Oliveira
6 */
7
8/*
9 * References:
10 * - Getting started with TS-CAN1, Technologic Systems, Jun 2009
11 *	http://www.embeddedarm.com/documentation/ts-can1-manual.pdf
12 */
13
14#include <linux/init.h>
15#include <linux/io.h>
16#include <linux/ioport.h>
17#include <linux/isa.h>
18#include <linux/module.h>
19#include <linux/netdevice.h>
20#include "sja1000.h"
21
22MODULE_DESCRIPTION("Driver for Technologic Systems TS-CAN1 PC104 boards");
23MODULE_AUTHOR("Andre B. Oliveira <anbadeol@gmail.com>");
24MODULE_LICENSE("GPL");
25
26/* Maximum number of boards (one in each JP1:JP2 setting of IO address) */
27#define TSCAN1_MAXDEV 4
28
29/* PLD registers address offsets */
30#define TSCAN1_ID1	0
31#define TSCAN1_ID2	1
32#define TSCAN1_VERSION	2
33#define TSCAN1_LED	3
34#define TSCAN1_PAGE	4
35#define TSCAN1_MODE	5
36#define TSCAN1_JUMPERS	6
37
38/* PLD board identifier registers magic values */
39#define TSCAN1_ID1_VALUE 0xf6
40#define TSCAN1_ID2_VALUE 0xb9
41
42/* PLD mode register SJA1000 IO enable bit */
43#define TSCAN1_MODE_ENABLE 0x40
44
45/* PLD jumpers register bits */
46#define TSCAN1_JP4 0x10
47#define TSCAN1_JP5 0x20
48
49/* PLD IO base addresses start */
50#define TSCAN1_PLD_ADDRESS 0x150
51
52/* PLD register space size */
53#define TSCAN1_PLD_SIZE 8
54
55/* SJA1000 register space size */
56#define TSCAN1_SJA1000_SIZE 32
57
58/* SJA1000 crystal frequency (16MHz) */
59#define TSCAN1_SJA1000_XTAL 16000000
60
61/* SJA1000 IO base addresses */
62static const unsigned short tscan1_sja1000_addresses[] = {
63	0x100, 0x120, 0x180, 0x1a0, 0x200, 0x240, 0x280, 0x320
64};
65
66/* Read SJA1000 register */
67static u8 tscan1_read(const struct sja1000_priv *priv, int reg)
68{
69	return inb((unsigned long)priv->reg_base + reg);
70}
71
72/* Write SJA1000 register */
73static void tscan1_write(const struct sja1000_priv *priv, int reg, u8 val)
74{
75	outb(val, (unsigned long)priv->reg_base + reg);
76}
77
78/* Probe for a TS-CAN1 board with JP2:JP1 jumper setting ID */
79static int tscan1_probe(struct device *dev, unsigned id)
80{
81	struct net_device *netdev;
82	struct sja1000_priv *priv;
83	unsigned long pld_base, sja1000_base;
84	int irq, i;
85
86	pld_base = TSCAN1_PLD_ADDRESS + id * TSCAN1_PLD_SIZE;
87	if (!request_region(pld_base, TSCAN1_PLD_SIZE, dev_name(dev)))
88		return -EBUSY;
89
90	if (inb(pld_base + TSCAN1_ID1) != TSCAN1_ID1_VALUE ||
91	    inb(pld_base + TSCAN1_ID2) != TSCAN1_ID2_VALUE) {
92		release_region(pld_base, TSCAN1_PLD_SIZE);
93		return -ENODEV;
94	}
95
96	switch (inb(pld_base + TSCAN1_JUMPERS) & (TSCAN1_JP4 | TSCAN1_JP5)) {
97	case TSCAN1_JP4:
98		irq = 6;
99		break;
100	case TSCAN1_JP5:
101		irq = 7;
102		break;
103	case TSCAN1_JP4 | TSCAN1_JP5:
104		irq = 5;
105		break;
106	default:
107		dev_err(dev, "invalid JP4:JP5 setting (no IRQ)\n");
108		release_region(pld_base, TSCAN1_PLD_SIZE);
109		return -EINVAL;
110	}
111
112	netdev = alloc_sja1000dev(0);
113	if (!netdev) {
114		release_region(pld_base, TSCAN1_PLD_SIZE);
115		return -ENOMEM;
116	}
117
118	dev_set_drvdata(dev, netdev);
119	SET_NETDEV_DEV(netdev, dev);
120
121	netdev->base_addr = pld_base;
122	netdev->irq = irq;
123
124	priv = netdev_priv(netdev);
125	priv->read_reg = tscan1_read;
126	priv->write_reg = tscan1_write;
127	priv->can.clock.freq = TSCAN1_SJA1000_XTAL / 2;
128	priv->cdr = CDR_CBP | CDR_CLK_OFF;
129	priv->ocr = OCR_TX0_PUSHPULL;
130
131	/* Select the first SJA1000 IO address that is free and that works */
132	for (i = 0; i < ARRAY_SIZE(tscan1_sja1000_addresses); i++) {
133		sja1000_base = tscan1_sja1000_addresses[i];
134		if (!request_region(sja1000_base, TSCAN1_SJA1000_SIZE,
135								dev_name(dev)))
136			continue;
137
138		/* Set SJA1000 IO base address and enable it */
139		outb(TSCAN1_MODE_ENABLE | i, pld_base + TSCAN1_MODE);
140
141		priv->reg_base = (void __iomem *)sja1000_base;
142		if (!register_sja1000dev(netdev)) {
143			/* SJA1000 probe succeeded; turn LED off and return */
144			outb(0, pld_base + TSCAN1_LED);
145			netdev_info(netdev, "TS-CAN1 at 0x%lx 0x%lx irq %d\n",
146						pld_base, sja1000_base, irq);
147			return 0;
148		}
149
150		/* SJA1000 probe failed; release and try next address */
151		outb(0, pld_base + TSCAN1_MODE);
152		release_region(sja1000_base, TSCAN1_SJA1000_SIZE);
153	}
154
155	dev_err(dev, "failed to assign SJA1000 IO address\n");
156	dev_set_drvdata(dev, NULL);
157	free_sja1000dev(netdev);
158	release_region(pld_base, TSCAN1_PLD_SIZE);
159	return -ENXIO;
160}
161
162static int tscan1_remove(struct device *dev, unsigned id /*unused*/)
163{
164	struct net_device *netdev;
165	struct sja1000_priv *priv;
166	unsigned long pld_base, sja1000_base;
167
168	netdev = dev_get_drvdata(dev);
169	unregister_sja1000dev(netdev);
170	dev_set_drvdata(dev, NULL);
171
172	priv = netdev_priv(netdev);
173	pld_base = netdev->base_addr;
174	sja1000_base = (unsigned long)priv->reg_base;
175
176	outb(0, pld_base + TSCAN1_MODE);	/* disable SJA1000 IO space */
177
178	release_region(sja1000_base, TSCAN1_SJA1000_SIZE);
179	release_region(pld_base, TSCAN1_PLD_SIZE);
180
181	free_sja1000dev(netdev);
182
183	return 0;
184}
185
186static struct isa_driver tscan1_isa_driver = {
187	.probe = tscan1_probe,
188	.remove = tscan1_remove,
189	.driver = {
190		.name = "tscan1",
191	},
192};
193
194module_isa_driver(tscan1_isa_driver, TSCAN1_MAXDEV);
195