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 /* Partially rewriten by Oleg I. Vdovikin for mmapped support of
  26    for Alpha Processor Inc. UP-2000(+) boards */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/ioport.h>
  30 #include <linux/module.h>
  31 #include <linux/delay.h>
  32 #include <linux/init.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/pci.h>
  35 #include <linux/wait.h>
  36
  37 #include <linux/isa.h>
  38 #include <linux/i2c.h>
  39 #include <linux/i2c-algo-pcf.h>
  40 #include <linux/io.h>
  41
  42 #include <asm/irq.h>
  43
  44 #include "../algos/i2c-algo-pcf.h"
  45
  46 #define DEFAULT_BASE 0x330
  47
  48 static int base;
  49 static u8 __iomem *base_iomem;
  50
  51 static int irq;
  52 static int clock  = 0x1c;
  53 static int own    = 0x55;
  54 static int mmapped;
  55
  56 /* vdovikin: removed static struct i2c_pcf_isa gpi; code -
  57   this module in real supports only one device, due to missing arguments
  58   in some functions, called from the algo-pcf module. Sometimes it's
  59   need to be rewriten - but for now just remove this for simpler reading */
  60
  61 static wait_queue_head_t pcf_wait;
  62 static int pcf_pending;
  63 static spinlock_t lock;
  64
  65 static struct i2c_adapter pcf_isa_ops;
  66
  67 /* ----- local functions ---------------------------------------------- */
  68
  69 static void pcf_isa_setbyte(void *data, int ctl, int val)
  70 {
  71         u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
  72
  73         /* enable irq if any specified for serial operation */
  74         if (ctl && irq && (val & I2C_PCF_ESO)) {
  75                 val |= I2C_PCF_ENI;
  76         }
  77
  78         pr_debug("%s: Write %p 0x%02X\n", pcf_isa_ops.name, address, val);
  79         iowrite8(val, address);
  80 #ifdef __alpha__
  81         /* API UP2000 needs some hardware fudging to make the write stick */
  82         iowrite8(val, address);
  83 #endif
  84 }
  85
  86 static int pcf_isa_getbyte(void *data, int ctl)
  87 {
  88         u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
  89         int val = ioread8(address);
  90
  91         pr_debug("%s: Read %p 0x%02X\n", pcf_isa_ops.name, address, val);
  92         return (val);
  93 }
  94
  95 static int pcf_isa_getown(void *data)
  96 {
  97         return (own);
  98 }
  99
 100
 101 static int pcf_isa_getclock(void *data)
 102 {
 103         return (clock);
 104 }
 105
 106 static void pcf_isa_waitforpin(void *data)
 107 {
 108         DEFINE_WAIT(wait);
 109         int timeout = 2;
 110         unsigned long flags;
 111
 112         if (irq > 0) {
 113                 spin_lock_irqsave(&lock, flags);
 114                 if (pcf_pending == 0) {
 115                         spin_unlock_irqrestore(&lock, flags);
 116                         prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
 117                         if (schedule_timeout(timeout*HZ)) {
 118                                 spin_lock_irqsave(&lock, flags);
 119                                 if (pcf_pending == 1) {
 120                                         pcf_pending = 0;
 121                                 }
 122                                 spin_unlock_irqrestore(&lock, flags);
 123                         }
 124                         finish_wait(&pcf_wait, &wait);
 125                 } else {
 126                         pcf_pending = 0;
 127                         spin_unlock_irqrestore(&lock, flags);
 128                 }
 129         } else {
 130                 udelay(100);
 131         }
 132 }
 133
 134
 135 static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id) {
 136         spin_lock(&lock);
 137         pcf_pending = 1;
 138         spin_unlock(&lock);
 139         wake_up_interruptible(&pcf_wait);
 140         return IRQ_HANDLED;
 141 }
 142
 143
 144 static int pcf_isa_init(void)
 145 {
 146         spin_lock_init(&lock);
 147         if (!mmapped) {
 148                 if (!request_region(base, 2, pcf_isa_ops.name)) {
 149                         printk(KERN_ERR "%s: requested I/O region (%#x:2) is "
 150                                "in use\n", pcf_isa_ops.name, base);
 151                         return -ENODEV;
 152                 }
 153                 base_iomem = ioport_map(base, 2);
 154                 if (!base_iomem) {
 155                         printk(KERN_ERR "%s: remap of I/O region %#x failed\n",
 156                                pcf_isa_ops.name, base);
 157                         release_region(base, 2);
 158                         return -ENODEV;
 159                 }
 160         } else {
 161                 if (!request_mem_region(base, 2, pcf_isa_ops.name)) {
 162                         printk(KERN_ERR "%s: requested memory region (%#x:2) "
 163                                "is in use\n", pcf_isa_ops.name, base);
 164                         return -ENODEV;
 165                 }
 166                 base_iomem = ioremap(base, 2);
 167                 if (base_iomem == NULL) {
 168                         printk(KERN_ERR "%s: remap of memory region %#x "
 169                                "failed\n", pcf_isa_ops.name, base);
 170                         release_mem_region(base, 2);
 171                         return -ENODEV;
 172                 }
 173         }
 174         pr_debug("%s: registers %#x remapped to %p\n", pcf_isa_ops.name, base,
 175                  base_iomem);
 176
 177         if (irq > 0) {
 178                 if (request_irq(irq, pcf_isa_handler, 0, pcf_isa_ops.name,
 179                                 NULL) < 0) {
 180                         printk(KERN_ERR "%s: Request irq%d failed\n",
 181                                pcf_isa_ops.name, irq);
 182                         irq = 0;
 183                 } else
 184                         enable_irq(irq);
 185         }
 186         return 0;
 187 }
 188
 189 /* ------------------------------------------------------------------------
 190  * Encapsulate the above functions in the correct operations structure.
 191  * This is only done when more than one hardware adapter is supported.
 192  */
 193 static struct i2c_algo_pcf_data pcf_isa_data = {
 194         .setpcf     = pcf_isa_setbyte,
 195         .getpcf     = pcf_isa_getbyte,
 196         .getown     = pcf_isa_getown,
 197         .getclock   = pcf_isa_getclock,
 198         .waitforpin = pcf_isa_waitforpin,
 199 };
 200
 201 static struct i2c_adapter pcf_isa_ops = {
 202         .owner          = THIS_MODULE,
 203         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 204         .algo_data      = &pcf_isa_data,
 205         .name           = "i2c-elektor",
 206 };
 207
 208 static int elektor_match(struct device *dev, unsigned int id)
 209 {
 210 #ifdef __alpha__
 211         /* check to see we have memory mapped PCF8584 connected to the
 212         Cypress cy82c693 PCI-ISA bridge as on UP2000 board */
 213         if (base == 0) {
 214                 struct pci_dev *cy693_dev;
 215
 216                 cy693_dev = pci_get_device(PCI_VENDOR_ID_CONTAQ,
 217                                            PCI_DEVICE_ID_CONTAQ_82C693, NULL);
 218                 if (cy693_dev) {
 219                         unsigned char config;
 220                         /* yeap, we've found cypress, let's check config */
 221                         if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {
 222
 223                                 dev_dbg(dev, "found cy82c693, config "
 224                                         "register 0x47 = 0x%02x\n", config);
 225
 226                                 /* UP2000 board has this register set to 0xe1,
 227                                    but the most significant bit as seems can be
 228                                    reset during the proper initialisation
 229                                    sequence if guys from API decides to do that
 230                                    (so, we can even enable Tsunami Pchip
 231                                    window for the upper 1 Gb) */
 232
 233                                 /* so just check for ROMCS at 0xe0000,
 234                                    ROMCS enabled for writes
 235                                    and external XD Bus buffer in use. */
 236                                 if ((config & 0x7f) == 0x61) {
 237                                         /* seems to be UP2000 like board */
 238                                         base = 0xe0000;
 239                                         mmapped = 1;
 240                                         /* UP2000 drives ISA with
 241                                            8.25 MHz (PCI/4) clock
 242                                            (this can be read from cypress) */
 243                                         clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
 244                                         dev_info(dev, "found API UP2000 like "
 245                                                  "board, will probe PCF8584 "
 246                                                  "later\n");
 247                                 }
 248                         }
 249                         pci_dev_put(cy693_dev);
 250                 }
 251         }
 252 #endif
 253
 254         /* sanity checks for mmapped I/O */
 255         if (mmapped && base < 0xc8000) {
 256                 dev_err(dev, "incorrect base address (%#x) specified "
 257                        "for mmapped I/O\n", base);
 258                 return 0;
 259         }
 260
 261         if (base == 0) {
 262                 base = DEFAULT_BASE;
 263         }
 264         return 1;
 265 }
 266
 267 static int elektor_probe(struct device *dev, unsigned int id)
 268 {
 269         init_waitqueue_head(&pcf_wait);
 270         if (pcf_isa_init())
 271                 return -ENODEV;
 272         pcf_isa_ops.dev.parent = dev;
 273         if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
 274                 goto fail;
 275
 276         dev_info(dev, "found device at %#x\n", base);
 277
 278         return 0;
 279
 280  fail:
 281         if (irq > 0) {
 282                 disable_irq(irq);
 283                 free_irq(irq, NULL);
 284         }
 285
 286         if (!mmapped) {
 287                 ioport_unmap(base_iomem);
 288                 release_region(base, 2);
 289         } else {
 290                 iounmap(base_iomem);
 291                 release_mem_region(base, 2);
 292         }
 293         return -ENODEV;
 294 }
 295
 296 static int elektor_remove(struct device *dev, unsigned int id)
 297 {
 298         i2c_del_adapter(&pcf_isa_ops);
 299
 300         if (irq > 0) {
 301                 disable_irq(irq);
 302                 free_irq(irq, NULL);
 303         }
 304
 305         if (!mmapped) {
 306                 ioport_unmap(base_iomem);
 307                 release_region(base, 2);
 308         } else {
 309                 iounmap(base_iomem);
 310                 release_mem_region(base, 2);
 311         }
 312
 313         return 0;
 314 }
 315
 316 static struct isa_driver i2c_elektor_driver = {
 317         .match          = elektor_match,
 318         .probe          = elektor_probe,
 319         .remove         = elektor_remove,
 320         .driver = {
 321                 .owner  = THIS_MODULE,
 322                 .name   = "i2c-elektor",
 323         },
 324 };
 325
 326 static int __init i2c_pcfisa_init(void)
 327 {
 328         return isa_register_driver(&i2c_elektor_driver, 1);
 329 }
 330
 331 static void __exit i2c_pcfisa_exit(void)
 332 {
 333         isa_unregister_driver(&i2c_elektor_driver);
 334 }
 335
 336 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
 337 MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
 338 MODULE_LICENSE("GPL");
 339
 340 module_param(base, int, 0);
 341 module_param(irq, int, 0);
 342 module_param(clock, int, 0);
 343 module_param(own, int, 0);
 344 module_param(mmapped, int, 0);
 345
 346 module_init(i2c_pcfisa_init);
 347 module_exit(i2c_pcfisa_exit);