drivers/i2c/busses/i2c-sis96x.c

   1 /*
   2     sis96x.c - Part of lm_sensors, Linux kernel modules for hardware
   3               monitoring
   4
   5     Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
   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 /*
  23     This module must be considered BETA unless and until
  24     the chipset manufacturer releases a datasheet.
  25     The register definitions are based on the SiS630.
  26
  27     This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c)
  28     for just about every machine for which users have reported.
  29     If this module isn't detecting your 96x south bridge, have a
  30     look there.
  31
  32     We assume there can only be one SiS96x with one SMBus interface.
  33 */
  34
  35 #include <linux/module.h>
  36 #include <linux/pci.h>
  37 #include <linux/kernel.h>
  38 #include <linux/delay.h>
  39 #include <linux/stddef.h>
  40 #include <linux/sched.h>
  41 #include <linux/ioport.h>
  42 #include <linux/i2c.h>
  43 #include <linux/init.h>
  44 #include <asm/io.h>
  45
  46 /*
  47         HISTORY:
  48         2003-05-11      1.0.0   Updated from lm_sensors project for kernel 2.5
  49                                 (was i2c-sis645.c from lm_sensors 2.7.0)
  50 */
  51 #define SIS96x_VERSION "1.0.0"
  52
  53 /* base address register in PCI config space */
  54 #define SIS96x_BAR 0x04
  55
  56 /* SiS96x SMBus registers */
  57 #define SMB_STS      0x00
  58 #define SMB_EN       0x01
  59 #define SMB_CNT      0x02
  60 #define SMB_HOST_CNT 0x03
  61 #define SMB_ADDR     0x04
  62 #define SMB_CMD      0x05
  63 #define SMB_PCOUNT   0x06
  64 #define SMB_COUNT    0x07
  65 #define SMB_BYTE     0x08
  66 #define SMB_DEV_ADDR 0x10
  67 #define SMB_DB0      0x11
  68 #define SMB_DB1      0x12
  69 #define SMB_SAA      0x13
  70
  71 /* register count for request_region */
  72 #define SMB_IOSIZE 0x20
  73
  74 /* Other settings */
  75 #define MAX_TIMEOUT 500
  76
  77 /* SiS96x SMBus constants */
  78 #define SIS96x_QUICK      0x00
  79 #define SIS96x_BYTE       0x01
  80 #define SIS96x_BYTE_DATA  0x02
  81 #define SIS96x_WORD_DATA  0x03
  82 #define SIS96x_PROC_CALL  0x04
  83 #define SIS96x_BLOCK_DATA 0x05
  84
  85 static struct pci_driver sis96x_driver;
  86 static struct i2c_adapter sis96x_adapter;
  87 static u16 sis96x_smbus_base;
  88
  89 static inline u8 sis96x_read(u8 reg)
  90 {
  91         return inb(sis96x_smbus_base + reg) ;
  92 }
  93
  94 static inline void sis96x_write(u8 reg, u8 data)
  95 {
  96         outb(data, sis96x_smbus_base + reg) ;
  97 }
  98
  99 /* Execute a SMBus transaction.
 100    int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA
 101  */
 102 static int sis96x_transaction(int size)
 103 {
 104         int temp;
 105         int result = 0;
 106         int timeout = 0;
 107
 108         dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size);
 109
 110         /* Make sure the SMBus host is ready to start transmitting */
 111         if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
 112
 113                 dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). "
 114                         "Resetting...\n", temp);
 115
 116                 /* kill the transaction */
 117                 sis96x_write(SMB_HOST_CNT, 0x20);
 118
 119                 /* check it again */
 120                 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
 121                         dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp);
 122                         return -1;
 123                 } else {
 124                         dev_dbg(&sis96x_adapter.dev, "Successful\n");
 125                 }
 126         }
 127
 128         /* Turn off timeout interrupts, set fast host clock */
 129         sis96x_write(SMB_CNT, 0x20);
 130
 131         /* clear all (sticky) status flags */
 132         temp = sis96x_read(SMB_STS);
 133         sis96x_write(SMB_STS, temp & 0x1e);
 134
 135         /* start the transaction by setting bit 4 and size bits */
 136         sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07));
 137
 138         /* We will always wait for a fraction of a second! */
 139         do {
 140                 msleep(1);
 141                 temp = sis96x_read(SMB_STS);
 142         } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT));
 143
 144         /* If the SMBus is still busy, we give up */
 145         if (timeout >= MAX_TIMEOUT) {
 146                 dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp);
 147                 result = -1;
 148         }
 149
 150         /* device error - probably missing ACK */
 151         if (temp & 0x02) {
 152                 dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n");
 153                 result = -1;
 154         }
 155
 156         /* bus collision */
 157         if (temp & 0x04) {
 158                 dev_dbg(&sis96x_adapter.dev, "Bus collision!\n");
 159                 result = -1;
 160         }
 161
 162         /* Finish up by resetting the bus */
 163         sis96x_write(SMB_STS, temp);
 164         if ((temp = sis96x_read(SMB_STS))) {
 165                 dev_dbg(&sis96x_adapter.dev, "Failed reset at "
 166                         "end of transaction! (0x%02x)\n", temp);
 167         }
 168
 169         return result;
 170 }
 171
 172 /* Return -1 on error. */
 173 static s32 sis96x_access(struct i2c_adapter * adap, u16 addr,
 174                          unsigned short flags, char read_write,
 175                          u8 command, int size, union i2c_smbus_data * data)
 176 {
 177
 178         switch (size) {
 179         case I2C_SMBUS_QUICK:
 180                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 181                 size = SIS96x_QUICK;
 182                 break;
 183
 184         case I2C_SMBUS_BYTE:
 185                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 186                 if (read_write == I2C_SMBUS_WRITE)
 187                         sis96x_write(SMB_CMD, command);
 188                 size = SIS96x_BYTE;
 189                 break;
 190
 191         case I2C_SMBUS_BYTE_DATA:
 192                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 193                 sis96x_write(SMB_CMD, command);
 194                 if (read_write == I2C_SMBUS_WRITE)
 195                         sis96x_write(SMB_BYTE, data->byte);
 196                 size = SIS96x_BYTE_DATA;
 197                 break;
 198
 199         case I2C_SMBUS_PROC_CALL:
 200         case I2C_SMBUS_WORD_DATA:
 201                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 202                 sis96x_write(SMB_CMD, command);
 203                 if (read_write == I2C_SMBUS_WRITE) {
 204                         sis96x_write(SMB_BYTE, data->word & 0xff);
 205                         sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8);
 206                 }
 207                 size = (size == I2C_SMBUS_PROC_CALL ?
 208                         SIS96x_PROC_CALL : SIS96x_WORD_DATA);
 209                 break;
 210
 211         case I2C_SMBUS_BLOCK_DATA:
 212                 /* TO DO: */
 213                 dev_info(&adap->dev, "SMBus block not implemented!\n");
 214                 return -1;
 215                 break;
 216
 217         default:
 218                 dev_info(&adap->dev, "Unsupported I2C size\n");
 219                 return -1;
 220                 break;
 221         }
 222
 223         if (sis96x_transaction(size))
 224                 return -1;
 225
 226         if ((size != SIS96x_PROC_CALL) &&
 227                 ((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK)))
 228                 return 0;
 229
 230         switch (size) {
 231         case SIS96x_BYTE:
 232         case SIS96x_BYTE_DATA:
 233                 data->byte = sis96x_read(SMB_BYTE);
 234                 break;
 235
 236         case SIS96x_WORD_DATA:
 237         case SIS96x_PROC_CALL:
 238                 data->word = sis96x_read(SMB_BYTE) +
 239                                 (sis96x_read(SMB_BYTE + 1) << 8);
 240                 break;
 241         }
 242         return 0;
 243 }
 244
 245 static u32 sis96x_func(struct i2c_adapter *adapter)
 246 {
 247         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 248             I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 249             I2C_FUNC_SMBUS_PROC_CALL;
 250 }
 251
 252 static struct i2c_algorithm smbus_algorithm = {
 253         .smbus_xfer     = sis96x_access,
 254         .functionality  = sis96x_func,
 255 };
 256
 257 static struct i2c_adapter sis96x_adapter = {
 258         .owner          = THIS_MODULE,
 259         .class          = I2C_CLASS_HWMON,
 260         .algo           = &smbus_algorithm,
 261 };
 262
 263 static struct pci_device_id sis96x_ids[] = {
 264         { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) },
 265         { 0, }
 266 };
 267
 268 MODULE_DEVICE_TABLE (pci, sis96x_ids);
 269
 270 static int __devinit sis96x_probe(struct pci_dev *dev,
 271                                 const struct pci_device_id *id)
 272 {
 273         u16 ww = 0;
 274         int retval;
 275
 276         if (sis96x_smbus_base) {
 277                 dev_err(&dev->dev, "Only one device supported.\n");
 278                 return -EBUSY;
 279         }
 280
 281         pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww);
 282         if (PCI_CLASS_SERIAL_SMBUS != ww) {
 283                 dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww);
 284                 return -ENODEV;
 285         }
 286
 287         sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR);
 288         if (!sis96x_smbus_base) {
 289                 dev_err(&dev->dev, "SiS96x SMBus base address "
 290                         "not initialized!\n");
 291                 return -EINVAL;
 292         }
 293         dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n",
 294                         sis96x_smbus_base);
 295
 296         /* Everything is happy, let's grab the memory and set things up. */
 297         if (!request_region(sis96x_smbus_base, SMB_IOSIZE,
 298                             sis96x_driver.name)) {
 299                 dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x "
 300                         "already in use!\n", sis96x_smbus_base,
 301                         sis96x_smbus_base + SMB_IOSIZE - 1);
 302
 303                 sis96x_smbus_base = 0;
 304                 return -EINVAL;
 305         }
 306
 307         /* set up the driverfs linkage to our parent device */
 308         sis96x_adapter.dev.parent = &dev->dev;
 309
 310         snprintf(sis96x_adapter.name, I2C_NAME_SIZE,
 311                 "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base);
 312
 313         if ((retval = i2c_add_adapter(&sis96x_adapter))) {
 314                 dev_err(&dev->dev, "Couldn't register adapter!\n");
 315                 release_region(sis96x_smbus_base, SMB_IOSIZE);
 316                 sis96x_smbus_base = 0;
 317         }
 318
 319         return retval;
 320 }
 321
 322 static void __devexit sis96x_remove(struct pci_dev *dev)
 323 {
 324         if (sis96x_smbus_base) {
 325                 i2c_del_adapter(&sis96x_adapter);
 326                 release_region(sis96x_smbus_base, SMB_IOSIZE);
 327                 sis96x_smbus_base = 0;
 328         }
 329 }
 330
 331 static struct pci_driver sis96x_driver = {
 332         .name           = "sis96x_smbus",
 333         .id_table       = sis96x_ids,
 334         .probe          = sis96x_probe,
 335         .remove         = __devexit_p(sis96x_remove),
 336 };
 337
 338 static int __init i2c_sis96x_init(void)
 339 {
 340         printk(KERN_INFO "i2c-sis96x version %s\n", SIS96x_VERSION);
 341         return pci_register_driver(&sis96x_driver);
 342 }
 343
 344 static void __exit i2c_sis96x_exit(void)
 345 {
 346         pci_unregister_driver(&sis96x_driver);
 347 }
 348
 349 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 350 MODULE_DESCRIPTION("SiS96x SMBus driver");
 351 MODULE_LICENSE("GPL");
 352
 353 /* Register initialization functions using helper macros */
 354 module_init(i2c_sis96x_init);
 355 module_exit(i2c_sis96x_exit);
 356