LXR linux/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
  75static struct pci_driver sis96x_driver;
  76static struct i2c_adapter sis96x_adapter;
  77static u16 sis96x_smbus_base;
  78
  79static inline u8 sis96x_read(u8 reg)
  80{
  81        return inb(sis96x_smbus_base + reg) ;
  82}
  83
  84static 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 */
  92static 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. */
 163static 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
 230static 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
 237static const struct i2c_algorithm smbus_algorithm = {
 238        .smbus_xfer     = sis96x_access,
 239        .functionality  = sis96x_func,
 240};
 241
 242static struct i2c_adapter sis96x_adapter = {
 243        .owner          = THIS_MODULE,
 244        .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 245        .algo           = &smbus_algorithm,
 246};
 247
 248static DEFINE_PCI_DEVICE_TABLE(sis96x_ids) = {
 249        { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) },
 250        { 0, }
 251};
 252
 253MODULE_DEVICE_TABLE (pci, sis96x_ids);
 254
 255static 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
 311static 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
 320static 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
 327static int __init i2c_sis96x_init(void)
 328{
 329        return pci_register_driver(&sis96x_driver);
 330}
 331
 332static void __exit i2c_sis96x_exit(void)
 333{
 334        pci_unregister_driver(&sis96x_driver);
 335}
 336
 337MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 338MODULE_DESCRIPTION("SiS96x SMBus driver");
 339MODULE_LICENSE("GPL");
 340
 341/* Register initialization functions using helper macros */
 342module_init(i2c_sis96x_init);
 343module_exit(i2c_sis96x_exit);
 344
 345