drivers/i2c/busses/i2c-isch.c

   1 /*
   2     i2c-isch.c - Linux kernel driver for Intel SCH chipset SMBus
   3     - Based on i2c-piix4.c
   4     Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and
   5     Philip Edelbrock <phil@netroedge.com>
   6     - Intel SCH support
   7     Copyright (c) 2007 - 2008 Jacob Jun Pan <jacob.jun.pan@intel.com>
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License version 2 as
  11     published by the Free Software Foundation.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 /*
  24    Supports:
  25         Intel SCH chipsets (AF82US15W, AF82US15L, AF82UL11L)
  26    Note: we assume there can only be one device, with one SMBus interface.
  27 */
  28
  29 #include <linux/module.h>
  30 #include <linux/pci.h>
  31 #include <linux/kernel.h>
  32 #include <linux/delay.h>
  33 #include <linux/stddef.h>
  34 #include <linux/ioport.h>
  35 #include <linux/i2c.h>
  36 #include <linux/init.h>
  37 #include <linux/io.h>
  38 #include <linux/acpi.h>
  39
  40 /* SCH SMBus address offsets */
  41 #define SMBHSTCNT       (0 + sch_smba)
  42 #define SMBHSTSTS       (1 + sch_smba)
  43 #define SMBHSTADD       (4 + sch_smba) /* TSA */
  44 #define SMBHSTCMD       (5 + sch_smba)
  45 #define SMBHSTDAT0      (6 + sch_smba)
  46 #define SMBHSTDAT1      (7 + sch_smba)
  47 #define SMBBLKDAT       (0x20 + sch_smba)
  48
  49 /* count for request_region */
  50 #define SMBIOSIZE       64
  51
  52 /* PCI Address Constants */
  53 #define SMBBA_SCH       0x40
  54
  55 /* Other settings */
  56 #define MAX_TIMEOUT     500
  57
  58 /* I2C constants */
  59 #define SCH_QUICK               0x00
  60 #define SCH_BYTE                0x01
  61 #define SCH_BYTE_DATA           0x02
  62 #define SCH_WORD_DATA           0x03
  63 #define SCH_BLOCK_DATA          0x05
  64
  65 static unsigned short sch_smba;
  66 static struct pci_driver sch_driver;
  67 static struct i2c_adapter sch_adapter;
  68
  69 /*
  70  * Start the i2c transaction -- the i2c_access will prepare the transaction
  71  * and this function will execute it.
  72  * return 0 for success and others for failure.
  73  */
  74 static int sch_transaction(void)
  75 {
  76         int temp;
  77         int result = 0;
  78         int timeout = 0;
  79
  80         dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
  81                 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
  82                 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
  83                 inb(SMBHSTDAT1));
  84
  85         /* Make sure the SMBus host is ready to start transmitting */
  86         temp = inb(SMBHSTSTS) & 0x0f;
  87         if (temp) {
  88                 /* Can not be busy since we checked it in sch_access */
  89                 if (temp & 0x01) {
  90                         dev_dbg(&sch_adapter.dev, "Completion (%02x). "
  91                                 "Clear...\n", temp);
  92                 }
  93                 if (temp & 0x06) {
  94                         dev_dbg(&sch_adapter.dev, "SMBus error (%02x). "
  95                                 "Resetting...\n", temp);
  96                 }
  97                 outb(temp, SMBHSTSTS);
  98                 temp = inb(SMBHSTSTS) & 0x0f;
  99                 if (temp) {
 100                         dev_err(&sch_adapter.dev,
 101                                 "SMBus is not ready: (%02x)\n", temp);
 102                         return -EAGAIN;
 103                 }
 104         }
 105
 106         /* start the transaction by setting bit 4 */
 107         outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT);
 108
 109         do {
 110                 msleep(1);
 111                 temp = inb(SMBHSTSTS) & 0x0f;
 112         } while ((temp & 0x08) && (timeout++ < MAX_TIMEOUT));
 113
 114         /* If the SMBus is still busy, we give up */
 115         if (timeout > MAX_TIMEOUT) {
 116                 dev_err(&sch_adapter.dev, "SMBus Timeout!\n");
 117                 result = -ETIMEDOUT;
 118         }
 119         if (temp & 0x04) {
 120                 result = -EIO;
 121                 dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be "
 122                         "locked until next hard reset. (sorry!)\n");
 123                 /* Clock stops and slave is stuck in mid-transmission */
 124         } else if (temp & 0x02) {
 125                 result = -EIO;
 126                 dev_err(&sch_adapter.dev, "Error: no response!\n");
 127         } else if (temp & 0x01) {
 128                 dev_dbg(&sch_adapter.dev, "Post complete!\n");
 129                 outb(temp, SMBHSTSTS);
 130                 temp = inb(SMBHSTSTS) & 0x07;
 131                 if (temp & 0x06) {
 132                         /* Completion clear failed */
 133                         dev_dbg(&sch_adapter.dev, "Failed reset at end of "
 134                                 "transaction (%02x), Bus error!\n", temp);
 135                 }
 136         } else {
 137                 result = -ENXIO;
 138                 dev_dbg(&sch_adapter.dev, "No such address.\n");
 139         }
 140         dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
 141                 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT),
 142                 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0),
 143                 inb(SMBHSTDAT1));
 144         return result;
 145 }
 146
 147 /*
 148  * This is the main access entry for i2c-sch access
 149  * adap is i2c_adapter pointer, addr is the i2c device bus address, read_write
 150  * (0 for read and 1 for write), size is i2c transaction type and data is the
 151  * union of transaction for data to be transfered or data read from bus.
 152  * return 0 for success and others for failure.
 153  */
 154 static s32 sch_access(struct i2c_adapter *adap, u16 addr,
 155                  unsigned short flags, char read_write,
 156                  u8 command, int size, union i2c_smbus_data *data)
 157 {
 158         int i, len, temp, rc;
 159
 160         /* Make sure the SMBus host is not busy */
 161         temp = inb(SMBHSTSTS) & 0x0f;
 162         if (temp & 0x08) {
 163                 dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
 164                 return -EAGAIN;
 165         }
 166         dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
 167                 (read_write)?"READ":"WRITE");
 168         switch (size) {
 169         case I2C_SMBUS_QUICK:
 170                 outb((addr << 1) | read_write, SMBHSTADD);
 171                 size = SCH_QUICK;
 172                 break;
 173         case I2C_SMBUS_BYTE:
 174                 outb((addr << 1) | read_write, SMBHSTADD);
 175                 if (read_write == I2C_SMBUS_WRITE)
 176                         outb(command, SMBHSTCMD);
 177                 size = SCH_BYTE;
 178                 break;
 179         case I2C_SMBUS_BYTE_DATA:
 180                 outb((addr << 1) | read_write, SMBHSTADD);
 181                 outb(command, SMBHSTCMD);
 182                 if (read_write == I2C_SMBUS_WRITE)
 183                         outb(data->byte, SMBHSTDAT0);
 184                 size = SCH_BYTE_DATA;
 185                 break;
 186         case I2C_SMBUS_WORD_DATA:
 187                 outb((addr << 1) | read_write, SMBHSTADD);
 188                 outb(command, SMBHSTCMD);
 189                 if (read_write == I2C_SMBUS_WRITE) {
 190                         outb(data->word & 0xff, SMBHSTDAT0);
 191                         outb((data->word & 0xff00) >> 8, SMBHSTDAT1);
 192                 }
 193                 size = SCH_WORD_DATA;
 194                 break;
 195         case I2C_SMBUS_BLOCK_DATA:
 196                 outb((addr << 1) | read_write, SMBHSTADD);
 197                 outb(command, SMBHSTCMD);
 198                 if (read_write == I2C_SMBUS_WRITE) {
 199                         len = data->block[0];
 200                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 201                                 return -EINVAL;
 202                         outb(len, SMBHSTDAT0);
 203                         for (i = 1; i <= len; i++)
 204                                 outb(data->block[i], SMBBLKDAT+i-1);
 205                 }
 206                 size = SCH_BLOCK_DATA;
 207                 break;
 208         default:
 209                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 210                 return -EOPNOTSUPP;
 211         }
 212         dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT);
 213         outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT);
 214
 215         rc = sch_transaction();
 216         if (rc) /* Error in transaction */
 217                 return rc;
 218
 219         if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK))
 220                 return 0;
 221
 222         switch (size) {
 223         case SCH_BYTE:
 224         case SCH_BYTE_DATA:
 225                 data->byte = inb(SMBHSTDAT0);
 226                 break;
 227         case SCH_WORD_DATA:
 228                 data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8);
 229                 break;
 230         case SCH_BLOCK_DATA:
 231                 data->block[0] = inb(SMBHSTDAT0);
 232                 if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
 233                         return -EPROTO;
 234                 for (i = 1; i <= data->block[0]; i++)
 235                         data->block[i] = inb(SMBBLKDAT+i-1);
 236                 break;
 237         }
 238         return 0;
 239 }
 240
 241 static u32 sch_func(struct i2c_adapter *adapter)
 242 {
 243         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 244             I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 245             I2C_FUNC_SMBUS_BLOCK_DATA;
 246 }
 247
 248 static const struct i2c_algorithm smbus_algorithm = {
 249         .smbus_xfer     = sch_access,
 250         .functionality  = sch_func,
 251 };
 252
 253 static struct i2c_adapter sch_adapter = {
 254         .owner          = THIS_MODULE,
 255         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 256         .algo           = &smbus_algorithm,
 257 };
 258
 259 static struct pci_device_id sch_ids[] = {
 260         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_SCH_LPC) },
 261         { 0, }
 262 };
 263
 264 MODULE_DEVICE_TABLE(pci, sch_ids);
 265
 266 static int __devinit sch_probe(struct pci_dev *dev,
 267                                 const struct pci_device_id *id)
 268 {
 269         int retval;
 270         unsigned int smba;
 271
 272         pci_read_config_dword(dev, SMBBA_SCH, &smba);
 273         if (!(smba & (1 << 31))) {
 274                 dev_err(&dev->dev, "SMBus I/O space disabled!\n");
 275                 return -ENODEV;
 276         }
 277
 278         sch_smba = (unsigned short)smba;
 279         if (sch_smba == 0) {
 280                 dev_err(&dev->dev, "SMBus base address uninitialized!\n");
 281                 return -ENODEV;
 282         }
 283         if (acpi_check_region(sch_smba, SMBIOSIZE, sch_driver.name))
 284                 return -ENODEV;
 285         if (!request_region(sch_smba, SMBIOSIZE, sch_driver.name)) {
 286                 dev_err(&dev->dev, "SMBus region 0x%x already in use!\n",
 287                         sch_smba);
 288                 return -EBUSY;
 289         }
 290         dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba);
 291
 292         /* set up the sysfs linkage to our parent device */
 293         sch_adapter.dev.parent = &dev->dev;
 294
 295         snprintf(sch_adapter.name, sizeof(sch_adapter.name),
 296                 "SMBus SCH adapter at %04x", sch_smba);
 297
 298         retval = i2c_add_adapter(&sch_adapter);
 299         if (retval) {
 300                 dev_err(&dev->dev, "Couldn't register adapter!\n");
 301                 release_region(sch_smba, SMBIOSIZE);
 302                 sch_smba = 0;
 303         }
 304
 305         return retval;
 306 }
 307
 308 static void __devexit sch_remove(struct pci_dev *dev)
 309 {
 310         if (sch_smba) {
 311                 i2c_del_adapter(&sch_adapter);
 312                 release_region(sch_smba, SMBIOSIZE);
 313                 sch_smba = 0;
 314         }
 315 }
 316
 317 static struct pci_driver sch_driver = {
 318         .name           = "isch_smbus",
 319         .id_table       = sch_ids,
 320         .probe          = sch_probe,
 321         .remove         = __devexit_p(sch_remove),
 322 };
 323
 324 static int __init i2c_sch_init(void)
 325 {
 326         return pci_register_driver(&sch_driver);
 327 }
 328
 329 static void __exit i2c_sch_exit(void)
 330 {
 331         pci_unregister_driver(&sch_driver);
 332 }
 333
 334 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>");
 335 MODULE_DESCRIPTION("Intel SCH SMBus driver");
 336 MODULE_LICENSE("GPL");
 337
 338 module_init(i2c_sch_init);
 339 module_exit(i2c_sch_exit);