drivers/i2c/busses/i2c-elektor.c

   1 /* ------------------------------------------------------------------------- */
   2 /* i2c-elektor.c i2c-hw access for PCF8584 style isa bus adaptes             */
   3 /* ------------------------------------------------------------------------- */
   4 /*   Copyright (C) 1995-97 Simon G. Vogl
   5                    1998-99 Hans Berglund
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with this program; if not, write to the Free Software
  19     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                */
  20 /* ------------------------------------------------------------------------- */
  21
  22 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even
  23    Frodo Looijaard <frodol@dds.nl> */
  24
  25 /* Partialy rewriten by Oleg I. Vdovikin for mmapped support of
  26    for Alpha Processor Inc. UP-2000(+) boards */
  27
  28 #include <linux/config.h>
  29 #include <linux/kernel.h>
  30 #include <linux/ioport.h>
  31 #include <linux/module.h>
  32 #include <linux/delay.h>
  33 #include <linux/slab.h>
  34 #include <linux/init.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/pci.h>
  37 #include <linux/wait.h>
  38
  39 #include <linux/i2c.h>
  40 #include <linux/i2c-algo-pcf.h>
  41
  42 #include <asm/io.h>
  43 #include <asm/irq.h>
  44
  45 #include "../algos/i2c-algo-pcf.h"
  46
  47 #define DEFAULT_BASE 0x330
  48
  49 static int base;
  50 static int irq;
  51 static int clock  = 0x1c;
  52 static int own    = 0x55;
  53 static int mmapped;
  54
  55 /* vdovikin: removed static struct i2c_pcf_isa gpi; code -
  56   this module in real supports only one device, due to missing arguments
  57   in some functions, called from the algo-pcf module. Sometimes it's
  58   need to be rewriten - but for now just remove this for simpler reading */
  59
  60 static wait_queue_head_t pcf_wait;
  61 static int pcf_pending;
  62 static spinlock_t lock;
  63
  64 /* ----- local functions ---------------------------------------------- */
  65
  66 static void pcf_isa_setbyte(void *data, int ctl, int val)
  67 {
  68         int address = ctl ? (base + 1) : base;
  69
  70         /* enable irq if any specified for serial operation */
  71         if (ctl && irq && (val & I2C_PCF_ESO)) {
  72                 val |= I2C_PCF_ENI;
  73         }
  74
  75         pr_debug("i2c-elektor: Write 0x%X 0x%02X\n", address, val & 255);
  76
  77         switch (mmapped) {
  78         case 0: /* regular I/O */
  79                 outb(val, address);
  80                 break;
  81         case 2: /* double mapped I/O needed for UP2000 board,
  82                    I don't know why this... */
  83                 writeb(val, (void *)address);
  84                 /* fall */
  85         case 1: /* memory mapped I/O */
  86                 writeb(val, (void *)address);
  87                 break;
  88         }
  89 }
  90
  91 static int pcf_isa_getbyte(void *data, int ctl)
  92 {
  93         int address = ctl ? (base + 1) : base;
  94         int val = mmapped ? readb((void *)address) : inb(address);
  95
  96         pr_debug("i2c-elektor: Read 0x%X 0x%02X\n", address, val);
  97
  98         return (val);
  99 }
 100
 101 static int pcf_isa_getown(void *data)
 102 {
 103         return (own);
 104 }
 105
 106
 107 static int pcf_isa_getclock(void *data)
 108 {
 109         return (clock);
 110 }
 111
 112 static void pcf_isa_waitforpin(void) {
 113
 114         int timeout = 2;
 115         long flags;
 116
 117         if (irq > 0) {
 118                 spin_lock_irqsave(&lock, flags);
 119                 if (pcf_pending == 0) {
 120                         spin_unlock_irqrestore(&lock, flags);
 121                         if (interruptible_sleep_on_timeout(&pcf_wait,
 122                                                                 timeout*HZ)) {
 123                                 spin_lock_irqsave(&lock, flags);
 124                                 if (pcf_pending == 1) {
 125                                         pcf_pending = 0;
 126                                 }
 127                                 spin_unlock_irqrestore(&lock, flags);
 128                         }
 129                 } else {
 130                         pcf_pending = 0;
 131                         spin_unlock_irqrestore(&lock, flags);
 132                 }
 133         } else {
 134                 udelay(100);
 135         }
 136 }
 137
 138
 139 static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
 140         spin_lock(&lock);
 141         pcf_pending = 1;
 142         spin_unlock(&lock);
 143         wake_up_interruptible(&pcf_wait);
 144         return IRQ_HANDLED;
 145 }
 146
 147
 148 static int pcf_isa_init(void)
 149 {
 150         spin_lock_init(&lock);
 151         if (!mmapped) {
 152                 if (!request_region(base, 2, "i2c (isa bus adapter)")) {
 153                         printk(KERN_ERR
 154                                "i2c-elektor: requested I/O region (0x%X:2) "
 155                                "is in use.\n", base);
 156                         return -ENODEV;
 157                 }
 158         }
 159         if (irq > 0) {
 160                 if (request_irq(irq, pcf_isa_handler, 0, "PCF8584", NULL) < 0) {
 161                         printk(KERN_ERR "i2c-elektor: Request irq%d failed\n", irq);
 162                         irq = 0;
 163                 } else
 164                         enable_irq(irq);
 165         }
 166         return 0;
 167 }
 168
 169 /* ------------------------------------------------------------------------
 170  * Encapsulate the above functions in the correct operations structure.
 171  * This is only done when more than one hardware adapter is supported.
 172  */
 173 static struct i2c_algo_pcf_data pcf_isa_data = {
 174         .setpcf     = pcf_isa_setbyte,
 175         .getpcf     = pcf_isa_getbyte,
 176         .getown     = pcf_isa_getown,
 177         .getclock   = pcf_isa_getclock,
 178         .waitforpin = pcf_isa_waitforpin,
 179         .udelay     = 10,
 180         .mdelay     = 10,
 181         .timeout    = 100,
 182 };
 183
 184 static struct i2c_adapter pcf_isa_ops = {
 185         .owner          = THIS_MODULE,
 186         .id             = I2C_HW_P_ELEK,
 187         .algo_data      = &pcf_isa_data,
 188         .name           = "PCF8584 ISA adapter",
 189 };
 190
 191 static int __init i2c_pcfisa_init(void)
 192 {
 193 #ifdef __alpha__
 194         /* check to see we have memory mapped PCF8584 connected to the
 195         Cypress cy82c693 PCI-ISA bridge as on UP2000 board */
 196         if (base == 0) {
 197                 struct pci_dev *cy693_dev;
 198
 199                 cy693_dev = pci_get_device(PCI_VENDOR_ID_CONTAQ,
 200                                            PCI_DEVICE_ID_CONTAQ_82C693, NULL);
 201                 if (cy693_dev) {
 202                         char config;
 203                         /* yeap, we've found cypress, let's check config */
 204                         if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {
 205
 206                                 pr_debug("i2c-elektor: found cy82c693, config register 0x47 = 0x%02x.\n", config);
 207
 208                                 /* UP2000 board has this register set to 0xe1,
 209                                    but the most significant bit as seems can be
 210                                    reset during the proper initialisation
 211                                    sequence if guys from API decides to do that
 212                                    (so, we can even enable Tsunami Pchip
 213                                    window for the upper 1 Gb) */
 214
 215                                 /* so just check for ROMCS at 0xe0000,
 216                                    ROMCS enabled for writes
 217                                    and external XD Bus buffer in use. */
 218                                 if ((config & 0x7f) == 0x61) {
 219                                         /* seems to be UP2000 like board */
 220                                         base = 0xe0000;
 221                                         /* I don't know why we need to
 222                                            write twice */
 223                                         mmapped = 2;
 224                                         /* UP2000 drives ISA with
 225                                            8.25 MHz (PCI/4) clock
 226                                            (this can be read from cypress) */
 227                                         clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
 228                                         printk(KERN_INFO "i2c-elektor: found API UP2000 like board, will probe PCF8584 later.\n");
 229                                 }
 230                         }
 231                         pci_dev_put(cy693_dev);
 232                 }
 233         }
 234 #endif
 235
 236         /* sanity checks for mmapped I/O */
 237         if (mmapped && base < 0xc8000) {
 238                 printk(KERN_ERR "i2c-elektor: incorrect base address (0x%0X) specified for mmapped I/O.\n", base);
 239                 return -ENODEV;
 240         }
 241
 242         printk(KERN_INFO "i2c-elektor: i2c pcf8584-isa adapter driver\n");
 243
 244         if (base == 0) {
 245                 base = DEFAULT_BASE;
 246         }
 247
 248         init_waitqueue_head(&pcf_wait);
 249         if (pcf_isa_init())
 250                 return -ENODEV;
 251         if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
 252                 goto fail;
 253
 254         printk(KERN_ERR "i2c-elektor: found device at %#x.\n", base);
 255
 256         return 0;
 257
 258  fail:
 259         if (irq > 0) {
 260                 disable_irq(irq);
 261                 free_irq(irq, NULL);
 262         }
 263
 264         if (!mmapped)
 265                 release_region(base , 2);
 266         return -ENODEV;
 267 }
 268
 269 static void i2c_pcfisa_exit(void)
 270 {
 271         i2c_pcf_del_bus(&pcf_isa_ops);
 272
 273         if (irq > 0) {
 274                 disable_irq(irq);
 275                 free_irq(irq, NULL);
 276         }
 277
 278         if (!mmapped)
 279                 release_region(base , 2);
 280 }
 281
 282 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
 283 MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
 284 MODULE_LICENSE("GPL");
 285
 286 module_param(base, int, 0);
 287 module_param(irq, int, 0);
 288 module_param(clock, int, 0);
 289 module_param(own, int, 0);
 290 module_param(mmapped, int, 0);
 291
 292 module_init(i2c_pcfisa_init);
 293 module_exit(i2c_pcfisa_exit);