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
21 MODULE_DESCRIPTION("Driver for Technologic Systems TS-CAN1 PC104 boards");
22 MODULE_AUTHOR("Andre B. Oliveira <anbadeol@gmail.com>");
23 MODULE_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 */
61 static const unsigned short tscan1_sja1000_addresses[] = {
62 0x100, 0x120, 0x180, 0x1a0, 0x200, 0x240, 0x280, 0x320
63 };
64
65 /* Read SJA1000 register */
tscan1_read(const struct sja1000_priv * priv,int reg)66 static 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 */
tscan1_write(const struct sja1000_priv * priv,int reg,u8 val)72 static 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 */
tscan1_probe(struct device * dev,unsigned id)78 static 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
tscan1_remove(struct device * dev,unsigned id)161 static 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
183 static struct isa_driver tscan1_isa_driver = {
184 .probe = tscan1_probe,
185 .remove = tscan1_remove,
186 .driver = {
187 .name = "tscan1",
188 },
189 };
190
191 module_isa_driver(tscan1_isa_driver, TSCAN1_MAXDEV);
192