drivers/i2c/busses/i2c-sis96x.c

   1 /*
   2     Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 /*
  20     This module must be considered BETA unless and until
  21     the chipset manufacturer releases a datasheet.
  22     The register definitions are based on the SiS630.
  23
  24     This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c)
  25     for just about every machine for which users have reported.
  26     If this module isn't detecting your 96x south bridge, have a
  27     look there.
  28
  29     We assume there can only be one SiS96x with one SMBus interface.
  30 */
  31
  32 #include <linux/module.h>
  33 #include <linux/pci.h>
  34 #include <linux/kernel.h>
  35 #include <linux/delay.h>
  36 #include <linux/stddef.h>
  37 #include <linux/ioport.h>
  38 #include <linux/i2c.h>
  39 #include <linux/init.h>
  40 #include <linux/acpi.h>
  41 #include <linux/io.h>
  42
  43 /* base address register in PCI config space */
  44 #define SIS96x_BAR 0x04
  45
  46 /* SiS96x SMBus registers */
  47 #define SMB_STS      0x00
  48 #define SMB_EN       0x01
  49 #define SMB_CNT      0x02
  50 #define SMB_HOST_CNT 0x03
  51 #define SMB_ADDR     0x04
  52 #define SMB_CMD      0x05
  53 #define SMB_PCOUNT   0x06
  54 #define SMB_COUNT    0x07
  55 #define SMB_BYTE     0x08
  56 #define SMB_DEV_ADDR 0x10
  57 #define SMB_DB0      0x11
  58 #define SMB_DB1      0x12
  59 #define SMB_SAA      0x13
  60
  61 /* register count for request_region */
  62 #define SMB_IOSIZE 0x20
  63
  64 /* Other settings */
  65 #define MAX_TIMEOUT 500
  66
  67 /* SiS96x SMBus constants */
  68 #define SIS96x_QUICK      0x00
  69 #define SIS96x_BYTE       0x01
  70 #define SIS96x_BYTE_DATA  0x02
  71 #define SIS96x_WORD_DATA  0x03
  72 #define SIS96x_PROC_CALL  0x04
  73 #define SIS96x_BLOCK_DATA 0x05
  74
  75 static struct pci_driver sis96x_driver;
  76 static struct i2c_adapter sis96x_adapter;
  77 static u16 sis96x_smbus_base;
  78
  79 static inline u8 sis96x_read(u8 reg)
  80 {
  81         return inb(sis96x_smbus_base + reg) ;
  82 }
  83
  84 static inline void sis96x_write(u8 reg, u8 data)
  85 {
  86         outb(data, sis96x_smbus_base + reg) ;
  87 }
  88
  89 /* Execute a SMBus transaction.
  90    int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA
  91  */
  92 static int sis96x_transaction(int size)
  93 {
  94         int temp;
  95         int result = 0;
  96         int timeout = 0;
  97
  98         dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size);
  99
 100         /* Make sure the SMBus host is ready to start transmitting */
 101         if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
 102
 103                 dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). "
 104                         "Resetting...\n", temp);
 105
 106                 /* kill the transaction */
 107                 sis96x_write(SMB_HOST_CNT, 0x20);
 108
 109                 /* check it again */
 110                 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
 111                         dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp);
 112                         return -EBUSY;
 113                 } else {
 114                         dev_dbg(&sis96x_adapter.dev, "Successful\n");
 115                 }
 116         }
 117
 118         /* Turn off timeout interrupts, set fast host clock */
 119         sis96x_write(SMB_CNT, 0x20);
 120
 121         /* clear all (sticky) status flags */
 122         temp = sis96x_read(SMB_STS);
 123         sis96x_write(SMB_STS, temp & 0x1e);
 124
 125         /* start the transaction by setting bit 4 and size bits */
 126         sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07));
 127
 128         /* We will always wait for a fraction of a second! */
 129         do {
 130                 msleep(1);
 131                 temp = sis96x_read(SMB_STS);
 132         } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT));
 133
 134         /* If the SMBus is still busy, we give up */
 135         if (timeout > MAX_TIMEOUT) {
 136                 dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp);
 137                 result = -ETIMEDOUT;
 138         }
 139
 140         /* device error - probably missing ACK */
 141         if (temp & 0x02) {
 142                 dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n");
 143                 result = -ENXIO;
 144         }
 145
 146         /* bus collision */
 147         if (temp & 0x04) {
 148                 dev_dbg(&sis96x_adapter.dev, "Bus collision!\n");
 149                 result = -EIO;
 150         }
 151
 152         /* Finish up by resetting the bus */
 153         sis96x_write(SMB_STS, temp);
 154         if ((temp = sis96x_read(SMB_STS))) {
 155                 dev_dbg(&sis96x_adapter.dev, "Failed reset at "
 156                         "end of transaction! (0x%02x)\n", temp);
 157         }
 158
 159         return result;
 160 }
 161
 162 /* Return negative errno on error. */
 163 static s32 sis96x_access(struct i2c_adapter * adap, u16 addr,
 164                          unsigned short flags, char read_write,
 165                          u8 command, int size, union i2c_smbus_data * data)
 166 {
 167         int status;
 168
 169         switch (size) {
 170         case I2C_SMBUS_QUICK:
 171                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 172                 size = SIS96x_QUICK;
 173                 break;
 174
 175         case I2C_SMBUS_BYTE:
 176                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 177                 if (read_write == I2C_SMBUS_WRITE)
 178                         sis96x_write(SMB_CMD, command);
 179                 size = SIS96x_BYTE;
 180                 break;
 181
 182         case I2C_SMBUS_BYTE_DATA:
 183                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 184                 sis96x_write(SMB_CMD, command);
 185                 if (read_write == I2C_SMBUS_WRITE)
 186                         sis96x_write(SMB_BYTE, data->byte);
 187                 size = SIS96x_BYTE_DATA;
 188                 break;
 189
 190         case I2C_SMBUS_PROC_CALL:
 191         case I2C_SMBUS_WORD_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->word & 0xff);
 196                         sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8);
 197                 }
 198                 size = (size == I2C_SMBUS_PROC_CALL ?
 199                         SIS96x_PROC_CALL : SIS96x_WORD_DATA);
 200                 break;
 201
 202         default:
 203                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 204                 return -EOPNOTSUPP;
 205         }
 206
 207         status = sis96x_transaction(size);
 208         if (status)
 209                 return status;
 210
 211         if ((size != SIS96x_PROC_CALL) &&
 212                 ((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK)))
 213                 return 0;
 214
 215         switch (size) {
 216         case SIS96x_BYTE:
 217         case SIS96x_BYTE_DATA:
 218                 data->byte = sis96x_read(SMB_BYTE);
 219                 break;
 220
 221         case SIS96x_WORD_DATA:
 222         case SIS96x_PROC_CALL:
 223                 data->word = sis96x_read(SMB_BYTE) +
 224                                 (sis96x_read(SMB_BYTE + 1) << 8);
 225                 break;
 226         }
 227         return 0;
 228 }
 229
 230 static u32 sis96x_func(struct i2c_adapter *adapter)
 231 {
 232         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 233             I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 234             I2C_FUNC_SMBUS_PROC_CALL;
 235 }
 236
 237 static const struct i2c_algorithm smbus_algorithm = {
 238         .smbus_xfer     = sis96x_access,
 239         .functionality  = sis96x_func,
 240 };
 241
 242 static struct i2c_adapter sis96x_adapter = {
 243         .owner          = THIS_MODULE,
 244         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 245         .algo           = &smbus_algorithm,
 246 };
 247
 248 static DEFINE_PCI_DEVICE_TABLE(sis96x_ids) = {
 249         { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) },
 250         { 0, }
 251 };
 252
 253 MODULE_DEVICE_TABLE (pci, sis96x_ids);
 254
 255 static int __devinit sis96x_probe(struct pci_dev *dev,
 256                                 const struct pci_device_id *id)
 257 {
 258         u16 ww = 0;
 259         int retval;
 260
 261         if (sis96x_smbus_base) {
 262                 dev_err(&dev->dev, "Only one device supported.\n");
 263                 return -EBUSY;
 264         }
 265
 266         pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww);
 267         if (PCI_CLASS_SERIAL_SMBUS != ww) {
 268                 dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww);
 269                 return -ENODEV;
 270         }
 271
 272         sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR);
 273         if (!sis96x_smbus_base) {
 274                 dev_err(&dev->dev, "SiS96x SMBus base address "
 275                         "not initialized!\n");
 276                 return -EINVAL;
 277         }
 278         dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n",
 279                         sis96x_smbus_base);
 280
 281         retval = acpi_check_resource_conflict(&dev->resource[SIS96x_BAR]);
 282         if (retval)
 283                 return -ENODEV;
 284
 285         /* Everything is happy, let's grab the memory and set things up. */
 286         if (!request_region(sis96x_smbus_base, SMB_IOSIZE,
 287                             sis96x_driver.name)) {
 288                 dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x "
 289                         "already in use!\n", sis96x_smbus_base,
 290                         sis96x_smbus_base + SMB_IOSIZE - 1);
 291
 292                 sis96x_smbus_base = 0;
 293                 return -EINVAL;
 294         }
 295
 296         /* set up the sysfs linkage to our parent device */
 297         sis96x_adapter.dev.parent = &dev->dev;
 298
 299         snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name),
 300                 "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base);
 301
 302         if ((retval = i2c_add_adapter(&sis96x_adapter))) {
 303                 dev_err(&dev->dev, "Couldn't register adapter!\n");
 304                 release_region(sis96x_smbus_base, SMB_IOSIZE);
 305                 sis96x_smbus_base = 0;
 306         }
 307
 308         return retval;
 309 }
 310
 311 static void __devexit sis96x_remove(struct pci_dev *dev)
 312 {
 313         if (sis96x_smbus_base) {
 314                 i2c_del_adapter(&sis96x_adapter);
 315                 release_region(sis96x_smbus_base, SMB_IOSIZE);
 316                 sis96x_smbus_base = 0;
 317         }
 318 }
 319
 320 static struct pci_driver sis96x_driver = {
 321         .name           = "sis96x_smbus",
 322         .id_table       = sis96x_ids,
 323         .probe          = sis96x_probe,
 324         .remove         = __devexit_p(sis96x_remove),
 325 };
 326
 327 static int __init i2c_sis96x_init(void)
 328 {
 329         return pci_register_driver(&sis96x_driver);
 330 }
 331
 332 static void __exit i2c_sis96x_exit(void)
 333 {
 334         pci_unregister_driver(&sis96x_driver);
 335 }
 336
 337 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 338 MODULE_DESCRIPTION("SiS96x SMBus driver");
 339 MODULE_LICENSE("GPL");
 340
 341 /* Register initialization functions using helper macros */
 342 module_init(i2c_sis96x_init);
 343 module_exit(i2c_sis96x_exit);
 344