drivers/net/can/sja1000/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
  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 */
  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 */
  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 */
  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
 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);