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
  18 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even
  19    Frodo Looijaard <frodol@dds.nl> */
  20
  21 /* Partially rewriten by Oleg I. Vdovikin for mmapped support of
  22    for Alpha Processor Inc. UP-2000(+) boards */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/ioport.h>
  26 #include <linux/module.h>
  27 #include <linux/delay.h>
  28 #include <linux/init.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/pci.h>
  31 #include <linux/wait.h>
  32
  33 #include <linux/isa.h>
  34 #include <linux/i2c.h>
  35 #include <linux/i2c-algo-pcf.h>
  36 #include <linux/io.h>
  37
  38 #include <asm/irq.h>
  39
  40 #include "../algos/i2c-algo-pcf.h"
  41
  42 #define DEFAULT_BASE 0x330
  43
  44 static int base;
  45 static u8 __iomem *base_iomem;
  46
  47 static int irq;
  48 static int clock  = 0x1c;
  49 static int own    = 0x55;
  50 static int mmapped;
  51
  52 /* vdovikin: removed static struct i2c_pcf_isa gpi; code -
  53   this module in real supports only one device, due to missing arguments
  54   in some functions, called from the algo-pcf module. Sometimes it's
  55   need to be rewriten - but for now just remove this for simpler reading */
  56
  57 static wait_queue_head_t pcf_wait;
  58 static int pcf_pending;
  59 static spinlock_t lock;
  60
  61 static struct i2c_adapter pcf_isa_ops;
  62
  63 /* ----- local functions ---------------------------------------------- */
  64
  65 static void pcf_isa_setbyte(void *data, int ctl, int val)
  66 {
  67         u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
  68
  69         /* enable irq if any specified for serial operation */
  70         if (ctl && irq && (val & I2C_PCF_ESO)) {
  71                 val |= I2C_PCF_ENI;
  72         }
  73
  74         pr_debug("%s: Write %p 0x%02X\n", pcf_isa_ops.name, address, val);
  75         iowrite8(val, address);
  76 #ifdef __alpha__
  77         /* API UP2000 needs some hardware fudging to make the write stick */
  78         iowrite8(val, address);
  79 #endif
  80 }
  81
  82 static int pcf_isa_getbyte(void *data, int ctl)
  83 {
  84         u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
  85         int val = ioread8(address);
  86
  87         pr_debug("%s: Read %p 0x%02X\n", pcf_isa_ops.name, address, val);
  88         return (val);
  89 }
  90
  91 static int pcf_isa_getown(void *data)
  92 {
  93         return (own);
  94 }
  95
  96
  97 static int pcf_isa_getclock(void *data)
  98 {
  99         return (clock);
 100 }
 101
 102 static void pcf_isa_waitforpin(void *data)
 103 {
 104         DEFINE_WAIT(wait);
 105         int timeout = 2;
 106         unsigned long flags;
 107
 108         if (irq > 0) {
 109                 spin_lock_irqsave(&lock, flags);
 110                 if (pcf_pending == 0) {
 111                         spin_unlock_irqrestore(&lock, flags);
 112                         prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
 113                         if (schedule_timeout(timeout*HZ)) {
 114                                 spin_lock_irqsave(&lock, flags);
 115                                 if (pcf_pending == 1) {
 116                                         pcf_pending = 0;
 117                                 }
 118                                 spin_unlock_irqrestore(&lock, flags);
 119                         }
 120                         finish_wait(&pcf_wait, &wait);
 121                 } else {
 122                         pcf_pending = 0;
 123                         spin_unlock_irqrestore(&lock, flags);
 124                 }
 125         } else {
 126                 udelay(100);
 127         }
 128 }
 129
 130
 131 static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id) {
 132         spin_lock(&lock);
 133         pcf_pending = 1;
 134         spin_unlock(&lock);
 135         wake_up_interruptible(&pcf_wait);
 136         return IRQ_HANDLED;
 137 }
 138
 139
 140 static int pcf_isa_init(void)
 141 {
 142         spin_lock_init(&lock);
 143         if (!mmapped) {
 144                 if (!request_region(base, 2, pcf_isa_ops.name)) {
 145                         printk(KERN_ERR "%s: requested I/O region (%#x:2) is "
 146                                "in use\n", pcf_isa_ops.name, base);
 147                         return -ENODEV;
 148                 }
 149                 base_iomem = ioport_map(base, 2);
 150                 if (!base_iomem) {
 151                         printk(KERN_ERR "%s: remap of I/O region %#x failed\n",
 152                                pcf_isa_ops.name, base);
 153                         release_region(base, 2);
 154                         return -ENODEV;
 155                 }
 156         } else {
 157                 if (!request_mem_region(base, 2, pcf_isa_ops.name)) {
 158                         printk(KERN_ERR "%s: requested memory region (%#x:2) "
 159                                "is in use\n", pcf_isa_ops.name, base);
 160                         return -ENODEV;
 161                 }
 162                 base_iomem = ioremap(base, 2);
 163                 if (base_iomem == NULL) {
 164                         printk(KERN_ERR "%s: remap of memory region %#x "
 165                                "failed\n", pcf_isa_ops.name, base);
 166                         release_mem_region(base, 2);
 167                         return -ENODEV;
 168                 }
 169         }
 170         pr_debug("%s: registers %#x remapped to %p\n", pcf_isa_ops.name, base,
 171                  base_iomem);
 172
 173         if (irq > 0) {
 174                 if (request_irq(irq, pcf_isa_handler, 0, pcf_isa_ops.name,
 175                                 NULL) < 0) {
 176                         printk(KERN_ERR "%s: Request irq%d failed\n",
 177                                pcf_isa_ops.name, irq);
 178                         irq = 0;
 179                 } else
 180                         enable_irq(irq);
 181         }
 182         return 0;
 183 }
 184
 185 /* ------------------------------------------------------------------------
 186  * Encapsulate the above functions in the correct operations structure.
 187  * This is only done when more than one hardware adapter is supported.
 188  */
 189 static struct i2c_algo_pcf_data pcf_isa_data = {
 190         .setpcf     = pcf_isa_setbyte,
 191         .getpcf     = pcf_isa_getbyte,
 192         .getown     = pcf_isa_getown,
 193         .getclock   = pcf_isa_getclock,
 194         .waitforpin = pcf_isa_waitforpin,
 195 };
 196
 197 static struct i2c_adapter pcf_isa_ops = {
 198         .owner          = THIS_MODULE,
 199         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 200         .algo_data      = &pcf_isa_data,
 201         .name           = "i2c-elektor",
 202 };
 203
 204 static int elektor_match(struct device *dev, unsigned int id)
 205 {
 206 #ifdef __alpha__
 207         /* check to see we have memory mapped PCF8584 connected to the
 208         Cypress cy82c693 PCI-ISA bridge as on UP2000 board */
 209         if (base == 0) {
 210                 struct pci_dev *cy693_dev;
 211
 212                 cy693_dev = pci_get_device(PCI_VENDOR_ID_CONTAQ,
 213                                            PCI_DEVICE_ID_CONTAQ_82C693, NULL);
 214                 if (cy693_dev) {
 215                         unsigned char config;
 216                         /* yeap, we've found cypress, let's check config */
 217                         if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {
 218
 219                                 dev_dbg(dev, "found cy82c693, config "
 220                                         "register 0x47 = 0x%02x\n", config);
 221
 222                                 /* UP2000 board has this register set to 0xe1,
 223                                    but the most significant bit as seems can be
 224                                    reset during the proper initialisation
 225                                    sequence if guys from API decides to do that
 226                                    (so, we can even enable Tsunami Pchip
 227                                    window for the upper 1 Gb) */
 228
 229                                 /* so just check for ROMCS at 0xe0000,
 230                                    ROMCS enabled for writes
 231                                    and external XD Bus buffer in use. */
 232                                 if ((config & 0x7f) == 0x61) {
 233                                         /* seems to be UP2000 like board */
 234                                         base = 0xe0000;
 235                                         mmapped = 1;
 236                                         /* UP2000 drives ISA with
 237                                            8.25 MHz (PCI/4) clock
 238                                            (this can be read from cypress) */
 239                                         clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
 240                                         dev_info(dev, "found API UP2000 like "
 241                                                  "board, will probe PCF8584 "
 242                                                  "later\n");
 243                                 }
 244                         }
 245                         pci_dev_put(cy693_dev);
 246                 }
 247         }
 248 #endif
 249
 250         /* sanity checks for mmapped I/O */
 251         if (mmapped && base < 0xc8000) {
 252                 dev_err(dev, "incorrect base address (%#x) specified "
 253                        "for mmapped I/O\n", base);
 254                 return 0;
 255         }
 256
 257         if (base == 0) {
 258                 base = DEFAULT_BASE;
 259         }
 260         return 1;
 261 }
 262
 263 static int elektor_probe(struct device *dev, unsigned int id)
 264 {
 265         init_waitqueue_head(&pcf_wait);
 266         if (pcf_isa_init())
 267                 return -ENODEV;
 268         pcf_isa_ops.dev.parent = dev;
 269         if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
 270                 goto fail;
 271
 272         dev_info(dev, "found device at %#x\n", base);
 273
 274         return 0;
 275
 276  fail:
 277         if (irq > 0) {
 278                 disable_irq(irq);
 279                 free_irq(irq, NULL);
 280         }
 281
 282         if (!mmapped) {
 283                 ioport_unmap(base_iomem);
 284                 release_region(base, 2);
 285         } else {
 286                 iounmap(base_iomem);
 287                 release_mem_region(base, 2);
 288         }
 289         return -ENODEV;
 290 }
 291
 292 static int elektor_remove(struct device *dev, unsigned int id)
 293 {
 294         i2c_del_adapter(&pcf_isa_ops);
 295
 296         if (irq > 0) {
 297                 disable_irq(irq);
 298                 free_irq(irq, NULL);
 299         }
 300
 301         if (!mmapped) {
 302                 ioport_unmap(base_iomem);
 303                 release_region(base, 2);
 304         } else {
 305                 iounmap(base_iomem);
 306                 release_mem_region(base, 2);
 307         }
 308
 309         return 0;
 310 }
 311
 312 static struct isa_driver i2c_elektor_driver = {
 313         .match          = elektor_match,
 314         .probe          = elektor_probe,
 315         .remove         = elektor_remove,
 316         .driver = {
 317                 .owner  = THIS_MODULE,
 318                 .name   = "i2c-elektor",
 319         },
 320 };
 321
 322 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
 323 MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
 324 MODULE_LICENSE("GPL");
 325
 326 module_param(base, int, 0);
 327 module_param(irq, int, 0);
 328 module_param(clock, int, 0);
 329 module_param(own, int, 0);
 330 module_param(mmapped, int, 0);
 331 module_isa_driver(i2c_elektor_driver, 1);