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