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/* References:
9 * - Getting started with TS-CAN1, Technologic Systems, Feb 2022
10 *	https://docs.embeddedts.com/TS-CAN1
11 */
12
13#include <linux/init.h>
14#include <linux/io.h>
15#include <linux/ioport.h>
16#include <linux/isa.h>
17#include <linux/module.h>
18#include <linux/netdevice.h>
19#include "sja1000.h"
20
21MODULE_DESCRIPTION("Driver for Technologic Systems TS-CAN1 PC104 boards");
22MODULE_AUTHOR("Andre B. Oliveira <anbadeol@gmail.com>");
23MODULE_LICENSE("GPL");
24
25/* Maximum number of boards (one in each JP1:JP2 setting of IO address) */
26#define TSCAN1_MAXDEV 4
27
28/* PLD registers address offsets */
29#define TSCAN1_ID1	0
30#define TSCAN1_ID2	1
31#define TSCAN1_VERSION	2
32#define TSCAN1_LED	3
33#define TSCAN1_PAGE	4
34#define TSCAN1_MODE	5
35#define TSCAN1_JUMPERS	6
36
37/* PLD board identifier registers magic values */
38#define TSCAN1_ID1_VALUE 0xf6
39#define TSCAN1_ID2_VALUE 0xb9
40
41/* PLD mode register SJA1000 IO enable bit */
42#define TSCAN1_MODE_ENABLE 0x40
43
44/* PLD jumpers register bits */
45#define TSCAN1_JP4 0x10
46#define TSCAN1_JP5 0x20
47
48/* PLD IO base addresses start */
49#define TSCAN1_PLD_ADDRESS 0x150
50
51/* PLD register space size */
52#define TSCAN1_PLD_SIZE 8
53
54/* SJA1000 register space size */
55#define TSCAN1_SJA1000_SIZE 32
56
57/* SJA1000 crystal frequency (16MHz) */
58#define TSCAN1_SJA1000_XTAL 16000000
59
60/* SJA1000 IO base addresses */
61static const unsigned short tscan1_sja1000_addresses[] = {
62	0x100, 0x120, 0x180, 0x1a0, 0x200, 0x240, 0x280, 0x320
63};
64
65/* Read SJA1000 register */
66static u8 tscan1_read(const struct sja1000_priv *priv, int reg)
67{
68	return inb((unsigned long)priv->reg_base + reg);
69}
70
71/* Write SJA1000 register */
72static void tscan1_write(const struct sja1000_priv *priv, int reg, u8 val)
73{
74	outb(val, (unsigned long)priv->reg_base + reg);
75}
76
77/* Probe for a TS-CAN1 board with JP2:JP1 jumper setting ID */
78static int tscan1_probe(struct device *dev, unsigned id)
79{
80	struct net_device *netdev;
81	struct sja1000_priv *priv;
82	unsigned long pld_base, sja1000_base;
83	int irq, i;
84
85	pld_base = TSCAN1_PLD_ADDRESS + id * TSCAN1_PLD_SIZE;
86	if (!request_region(pld_base, TSCAN1_PLD_SIZE, dev_name(dev)))
87		return -EBUSY;
88
89	if (inb(pld_base + TSCAN1_ID1) != TSCAN1_ID1_VALUE ||
90	    inb(pld_base + TSCAN1_ID2) != TSCAN1_ID2_VALUE) {
91		release_region(pld_base, TSCAN1_PLD_SIZE);
92		return -ENODEV;
93	}
94
95	switch (inb(pld_base + TSCAN1_JUMPERS) & (TSCAN1_JP4 | TSCAN1_JP5)) {
96	case TSCAN1_JP4:
97		irq = 6;
98		break;
99	case TSCAN1_JP5:
100		irq = 7;
101		break;
102	case TSCAN1_JP4 | TSCAN1_JP5:
103		irq = 5;
104		break;
105	default:
106		dev_err(dev, "invalid JP4:JP5 setting (no IRQ)\n");
107		release_region(pld_base, TSCAN1_PLD_SIZE);
108		return -EINVAL;
109	}
110
111	netdev = alloc_sja1000dev(0);
112	if (!netdev) {
113		release_region(pld_base, TSCAN1_PLD_SIZE);
114		return -ENOMEM;
115	}
116
117	dev_set_drvdata(dev, netdev);
118	SET_NETDEV_DEV(netdev, dev);
119
120	netdev->base_addr = pld_base;
121	netdev->irq = irq;
122
123	priv = netdev_priv(netdev);
124	priv->read_reg = tscan1_read;
125	priv->write_reg = tscan1_write;
126	priv->can.clock.freq = TSCAN1_SJA1000_XTAL / 2;
127	priv->cdr = CDR_CBP | CDR_CLK_OFF;
128	priv->ocr = OCR_TX0_PUSHPULL;
129
130	/* Select the first SJA1000 IO address that is free and that works */
131	for (i = 0; i < ARRAY_SIZE(tscan1_sja1000_addresses); i++) {
132		sja1000_base = tscan1_sja1000_addresses[i];
133		if (!request_region(sja1000_base, TSCAN1_SJA1000_SIZE,
134								dev_name(dev)))
135			continue;
136
137		/* Set SJA1000 IO base address and enable it */
138		outb(TSCAN1_MODE_ENABLE | i, pld_base + TSCAN1_MODE);
139
140		priv->reg_base = (void __iomem *)sja1000_base;
141		if (!register_sja1000dev(netdev)) {
142			/* SJA1000 probe succeeded; turn LED off and return */
143			outb(0, pld_base + TSCAN1_LED);
144			netdev_info(netdev, "TS-CAN1 at 0x%lx 0x%lx irq %d\n",
145						pld_base, sja1000_base, irq);
146			return 0;
147		}
148
149		/* SJA1000 probe failed; release and try next address */
150		outb(0, pld_base + TSCAN1_MODE);
151		release_region(sja1000_base, TSCAN1_SJA1000_SIZE);
152	}
153
154	dev_err(dev, "failed to assign SJA1000 IO address\n");
155	dev_set_drvdata(dev, NULL);
156	free_sja1000dev(netdev);
157	release_region(pld_base, TSCAN1_PLD_SIZE);
158	return -ENXIO;
159}
160
161static void tscan1_remove(struct device *dev, unsigned id /*unused*/)
162{
163	struct net_device *netdev;
164	struct sja1000_priv *priv;
165	unsigned long pld_base, sja1000_base;
166
167	netdev = dev_get_drvdata(dev);
168	unregister_sja1000dev(netdev);
169	dev_set_drvdata(dev, NULL);
170
171	priv = netdev_priv(netdev);
172	pld_base = netdev->base_addr;
173	sja1000_base = (unsigned long)priv->reg_base;
174
175	outb(0, pld_base + TSCAN1_MODE);	/* disable SJA1000 IO space */
176
177	release_region(sja1000_base, TSCAN1_SJA1000_SIZE);
178	release_region(pld_base, TSCAN1_PLD_SIZE);
179
180	free_sja1000dev(netdev);
181}
182
183static struct isa_driver tscan1_isa_driver = {
184	.probe = tscan1_probe,
185	.remove = tscan1_remove,
186	.driver = {
187		.name = "tscan1",
188	},
189};
190
191module_isa_driver(tscan1_isa_driver, TSCAN1_MAXDEV);
192