tscan1.c

  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);