drivers/i2c/busses/i2c-sis96x.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3     Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
   4
   5 */
   6
   7 /*
   8     This module must be considered BETA unless and until
   9     the chipset manufacturer releases a datasheet.
  10     The register definitions are based on the SiS630.
  11
  12     This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c)
  13     for just about every machine for which users have reported.
  14     If this module isn't detecting your 96x south bridge, have a
  15     look there.
  16
  17     We assume there can only be one SiS96x with one SMBus interface.
  18 */
  19
  20 #include <linux/module.h>
  21 #include <linux/pci.h>
  22 #include <linux/kernel.h>
  23 #include <linux/delay.h>
  24 #include <linux/stddef.h>
  25 #include <linux/ioport.h>
  26 #include <linux/i2c.h>
  27 #include <linux/acpi.h>
  28 #include <linux/io.h>
  29
  30 /* base address register in PCI config space */
  31 #define SIS96x_BAR 0x04
  32
  33 /* SiS96x SMBus registers */
  34 #define SMB_STS      0x00
  35 #define SMB_EN       0x01
  36 #define SMB_CNT      0x02
  37 #define SMB_HOST_CNT 0x03
  38 #define SMB_ADDR     0x04
  39 #define SMB_CMD      0x05
  40 #define SMB_PCOUNT   0x06
  41 #define SMB_COUNT    0x07
  42 #define SMB_BYTE     0x08
  43 #define SMB_DEV_ADDR 0x10
  44 #define SMB_DB0      0x11
  45 #define SMB_DB1      0x12
  46 #define SMB_SAA      0x13
  47
  48 /* register count for request_region */
  49 #define SMB_IOSIZE 0x20
  50
  51 /* Other settings */
  52 #define MAX_TIMEOUT 500
  53
  54 /* SiS96x SMBus constants */
  55 #define SIS96x_QUICK      0x00
  56 #define SIS96x_BYTE       0x01
  57 #define SIS96x_BYTE_DATA  0x02
  58 #define SIS96x_WORD_DATA  0x03
  59 #define SIS96x_PROC_CALL  0x04
  60 #define SIS96x_BLOCK_DATA 0x05
  61
  62 static struct pci_driver sis96x_driver;
  63 static struct i2c_adapter sis96x_adapter;
  64 static u16 sis96x_smbus_base;
  65
  66 static inline u8 sis96x_read(u8 reg)
  67 {
  68         return inb(sis96x_smbus_base + reg) ;
  69 }
  70
  71 static inline void sis96x_write(u8 reg, u8 data)
  72 {
  73         outb(data, sis96x_smbus_base + reg) ;
  74 }
  75
  76 /* Execute a SMBus transaction.
  77    int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA
  78  */
  79 static int sis96x_transaction(int size)
  80 {
  81         int temp;
  82         int result = 0;
  83         int timeout = 0;
  84
  85         dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size);
  86
  87         /* Make sure the SMBus host is ready to start transmitting */
  88         if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
  89
  90                 dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). "
  91                         "Resetting...\n", temp);
  92
  93                 /* kill the transaction */
  94                 sis96x_write(SMB_HOST_CNT, 0x20);
  95
  96                 /* check it again */
  97                 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
  98                         dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp);
  99                         return -EBUSY;
 100                 } else {
 101                         dev_dbg(&sis96x_adapter.dev, "Successful\n");
 102                 }
 103         }
 104
 105         /* Turn off timeout interrupts, set fast host clock */
 106         sis96x_write(SMB_CNT, 0x20);
 107
 108         /* clear all (sticky) status flags */
 109         temp = sis96x_read(SMB_STS);
 110         sis96x_write(SMB_STS, temp & 0x1e);
 111
 112         /* start the transaction by setting bit 4 and size bits */
 113         sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07));
 114
 115         /* We will always wait for a fraction of a second! */
 116         do {
 117                 msleep(1);
 118                 temp = sis96x_read(SMB_STS);
 119         } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT));
 120
 121         /* If the SMBus is still busy, we give up */
 122         if (timeout > MAX_TIMEOUT) {
 123                 dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp);
 124                 result = -ETIMEDOUT;
 125         }
 126
 127         /* device error - probably missing ACK */
 128         if (temp & 0x02) {
 129                 dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n");
 130                 result = -ENXIO;
 131         }
 132
 133         /* bus collision */
 134         if (temp & 0x04) {
 135                 dev_dbg(&sis96x_adapter.dev, "Bus collision!\n");
 136                 result = -EIO;
 137         }
 138
 139         /* Finish up by resetting the bus */
 140         sis96x_write(SMB_STS, temp);
 141         if ((temp = sis96x_read(SMB_STS))) {
 142                 dev_dbg(&sis96x_adapter.dev, "Failed reset at "
 143                         "end of transaction! (0x%02x)\n", temp);
 144         }
 145
 146         return result;
 147 }
 148
 149 /* Return negative errno on error. */
 150 static s32 sis96x_access(struct i2c_adapter * adap, u16 addr,
 151                          unsigned short flags, char read_write,
 152                          u8 command, int size, union i2c_smbus_data * data)
 153 {
 154         int status;
 155
 156         switch (size) {
 157         case I2C_SMBUS_QUICK:
 158                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 159                 size = SIS96x_QUICK;
 160                 break;
 161
 162         case I2C_SMBUS_BYTE:
 163                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 164                 if (read_write == I2C_SMBUS_WRITE)
 165                         sis96x_write(SMB_CMD, command);
 166                 size = SIS96x_BYTE;
 167                 break;
 168
 169         case I2C_SMBUS_BYTE_DATA:
 170                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 171                 sis96x_write(SMB_CMD, command);
 172                 if (read_write == I2C_SMBUS_WRITE)
 173                         sis96x_write(SMB_BYTE, data->byte);
 174                 size = SIS96x_BYTE_DATA;
 175                 break;
 176
 177         case I2C_SMBUS_PROC_CALL:
 178         case I2C_SMBUS_WORD_DATA:
 179                 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
 180                 sis96x_write(SMB_CMD, command);
 181                 if (read_write == I2C_SMBUS_WRITE) {
 182                         sis96x_write(SMB_BYTE, data->word & 0xff);
 183                         sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8);
 184                 }
 185                 size = (size == I2C_SMBUS_PROC_CALL ?
 186                         SIS96x_PROC_CALL : SIS96x_WORD_DATA);
 187                 break;
 188
 189         default:
 190                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 191                 return -EOPNOTSUPP;
 192         }
 193
 194         status = sis96x_transaction(size);
 195         if (status)
 196                 return status;
 197
 198         if ((size != SIS96x_PROC_CALL) &&
 199                 ((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK)))
 200                 return 0;
 201
 202         switch (size) {
 203         case SIS96x_BYTE:
 204         case SIS96x_BYTE_DATA:
 205                 data->byte = sis96x_read(SMB_BYTE);
 206                 break;
 207
 208         case SIS96x_WORD_DATA:
 209         case SIS96x_PROC_CALL:
 210                 data->word = sis96x_read(SMB_BYTE) +
 211                                 (sis96x_read(SMB_BYTE + 1) << 8);
 212                 break;
 213         }
 214         return 0;
 215 }
 216
 217 static u32 sis96x_func(struct i2c_adapter *adapter)
 218 {
 219         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 220             I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 221             I2C_FUNC_SMBUS_PROC_CALL;
 222 }
 223
 224 static const struct i2c_algorithm smbus_algorithm = {
 225         .smbus_xfer     = sis96x_access,
 226         .functionality  = sis96x_func,
 227 };
 228
 229 static struct i2c_adapter sis96x_adapter = {
 230         .owner          = THIS_MODULE,
 231         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 232         .algo           = &smbus_algorithm,
 233 };
 234
 235 static const struct pci_device_id sis96x_ids[] = {
 236         { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) },
 237         { 0, }
 238 };
 239
 240 MODULE_DEVICE_TABLE (pci, sis96x_ids);
 241
 242 static int sis96x_probe(struct pci_dev *dev,
 243                                 const struct pci_device_id *id)
 244 {
 245         u16 ww = 0;
 246         int retval;
 247
 248         if (sis96x_smbus_base) {
 249                 dev_err(&dev->dev, "Only one device supported.\n");
 250                 return -EBUSY;
 251         }
 252
 253         pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww);
 254         if (PCI_CLASS_SERIAL_SMBUS != ww) {
 255                 dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww);
 256                 return -ENODEV;
 257         }
 258
 259         sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR);
 260         if (!sis96x_smbus_base) {
 261                 dev_err(&dev->dev, "SiS96x SMBus base address "
 262                         "not initialized!\n");
 263                 return -EINVAL;
 264         }
 265         dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n",
 266                         sis96x_smbus_base);
 267
 268         retval = acpi_check_resource_conflict(&dev->resource[SIS96x_BAR]);
 269         if (retval)
 270                 return -ENODEV;
 271
 272         /* Everything is happy, let's grab the memory and set things up. */
 273         if (!request_region(sis96x_smbus_base, SMB_IOSIZE,
 274                             sis96x_driver.name)) {
 275                 dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x "
 276                         "already in use!\n", sis96x_smbus_base,
 277                         sis96x_smbus_base + SMB_IOSIZE - 1);
 278
 279                 sis96x_smbus_base = 0;
 280                 return -EINVAL;
 281         }
 282
 283         /* set up the sysfs linkage to our parent device */
 284         sis96x_adapter.dev.parent = &dev->dev;
 285
 286         snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name),
 287                 "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base);
 288
 289         if ((retval = i2c_add_adapter(&sis96x_adapter))) {
 290                 dev_err(&dev->dev, "Couldn't register adapter!\n");
 291                 release_region(sis96x_smbus_base, SMB_IOSIZE);
 292                 sis96x_smbus_base = 0;
 293         }
 294
 295         return retval;
 296 }
 297
 298 static void sis96x_remove(struct pci_dev *dev)
 299 {
 300         if (sis96x_smbus_base) {
 301                 i2c_del_adapter(&sis96x_adapter);
 302                 release_region(sis96x_smbus_base, SMB_IOSIZE);
 303                 sis96x_smbus_base = 0;
 304         }
 305 }
 306
 307 static struct pci_driver sis96x_driver = {
 308         .name           = "sis96x_smbus",
 309         .id_table       = sis96x_ids,
 310         .probe          = sis96x_probe,
 311         .remove         = sis96x_remove,
 312 };
 313
 314 module_pci_driver(sis96x_driver);
 315
 316 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 317 MODULE_DESCRIPTION("SiS96x SMBus driver");
 318 MODULE_LICENSE("GPL");