drivers/i2c/busses/i2c-powermac.c

   1 /*
   2     i2c Support for Apple SMU Controller
   3
   4     Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
   5                        <benh@kernel.crashing.org>
   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 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/types.h>
  26 #include <linux/i2c.h>
  27 #include <linux/init.h>
  28 #include <linux/device.h>
  29 #include <linux/platform_device.h>
  30 #include <asm/prom.h>
  31 #include <asm/pmac_low_i2c.h>
  32
  33 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  34 MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
  35 MODULE_LICENSE("GPL");
  36
  37 /*
  38  * SMBUS-type transfer entrypoint
  39  */
  40 static s32 i2c_powermac_smbus_xfer(     struct i2c_adapter*     adap,
  41                                         u16                     addr,
  42                                         unsigned short          flags,
  43                                         char                    read_write,
  44                                         u8                      command,
  45                                         int                     size,
  46                                         union i2c_smbus_data*   data)
  47 {
  48         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
  49         int                     rc = 0;
  50         int                     read = (read_write == I2C_SMBUS_READ);
  51         int                     addrdir = (addr << 1) | read;
  52         int                     mode, subsize, len;
  53         u32                     subaddr;
  54         u8                      *buf;
  55         u8                      local[2];
  56
  57         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) {
  58                 mode = pmac_i2c_mode_std;
  59                 subsize = 0;
  60                 subaddr = 0;
  61         } else {
  62                 mode = read ? pmac_i2c_mode_combined : pmac_i2c_mode_stdsub;
  63                 subsize = 1;
  64                 subaddr = command;
  65         }
  66
  67         switch (size) {
  68         case I2C_SMBUS_QUICK:
  69                 buf = NULL;
  70                 len = 0;
  71                 break;
  72         case I2C_SMBUS_BYTE:
  73         case I2C_SMBUS_BYTE_DATA:
  74                 buf = &data->byte;
  75                 len = 1;
  76                 break;
  77         case I2C_SMBUS_WORD_DATA:
  78                 if (!read) {
  79                         local[0] = data->word & 0xff;
  80                         local[1] = (data->word >> 8) & 0xff;
  81                 }
  82                 buf = local;
  83                 len = 2;
  84                 break;
  85
  86         /* Note that these are broken vs. the expected smbus API where
  87          * on reads, the length is actually returned from the function,
  88          * but I think the current API makes no sense and I don't want
  89          * any driver that I haven't verified for correctness to go
  90          * anywhere near a pmac i2c bus anyway ...
  91          *
  92          * I'm also not completely sure what kind of phases to do between
  93          * the actual command and the data (what I am _supposed_ to do that
  94          * is). For now, I assume writes are a single stream and reads have
  95          * a repeat start/addr phase (but not stop in between)
  96          */
  97         case I2C_SMBUS_BLOCK_DATA:
  98                 buf = data->block;
  99                 len = data->block[0] + 1;
 100                 break;
 101         case I2C_SMBUS_I2C_BLOCK_DATA:
 102                 buf = &data->block[1];
 103                 len = data->block[0];
 104                 break;
 105
 106         default:
 107                 return -EINVAL;
 108         }
 109
 110         rc = pmac_i2c_open(bus, 0);
 111         if (rc) {
 112                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
 113                 return rc;
 114         }
 115
 116         rc = pmac_i2c_setmode(bus, mode);
 117         if (rc) {
 118                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 119                         mode, rc);
 120                 goto bail;
 121         }
 122
 123         rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
 124         if (rc) {
 125                 if (rc == -ENXIO)
 126                         dev_dbg(&adap->dev,
 127                                 "I2C transfer at 0x%02x failed, size %d, "
 128                                 "err %d\n", addrdir >> 1, size, rc);
 129                 else
 130                         dev_err(&adap->dev,
 131                                 "I2C transfer at 0x%02x failed, size %d, "
 132                                 "err %d\n", addrdir >> 1, size, rc);
 133                 goto bail;
 134         }
 135
 136         if (size == I2C_SMBUS_WORD_DATA && read) {
 137                 data->word = ((u16)local[1]) << 8;
 138                 data->word |= local[0];
 139         }
 140
 141  bail:
 142         pmac_i2c_close(bus);
 143         return rc;
 144 }
 145
 146 /*
 147  * Generic i2c master transfer entrypoint. This driver only support single
 148  * messages (for "lame i2c" transfers). Anything else should use the smbus
 149  * entry point
 150  */
 151 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
 152                                         struct i2c_msg *msgs,
 153                                         int num)
 154 {
 155         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 156         int                     rc = 0;
 157         int                     read;
 158         int                     addrdir;
 159
 160         if (num != 1) {
 161                 dev_err(&adap->dev,
 162                         "Multi-message I2C transactions not supported\n");
 163                 return -EOPNOTSUPP;
 164         }
 165
 166         if (msgs->flags & I2C_M_TEN)
 167                 return -EINVAL;
 168         read = (msgs->flags & I2C_M_RD) != 0;
 169         addrdir = (msgs->addr << 1) | read;
 170
 171         rc = pmac_i2c_open(bus, 0);
 172         if (rc) {
 173                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
 174                 return rc;
 175         }
 176         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 177         if (rc) {
 178                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 179                         pmac_i2c_mode_std, rc);
 180                 goto bail;
 181         }
 182         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 183         if (rc < 0) {
 184                 if (rc == -ENXIO)
 185                         dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 186                                 addrdir & 1 ? "read from" : "write to",
 187                                 addrdir >> 1, rc);
 188                 else
 189                         dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 190                                 addrdir & 1 ? "read from" : "write to",
 191                                 addrdir >> 1, rc);
 192         }
 193  bail:
 194         pmac_i2c_close(bus);
 195         return rc < 0 ? rc : 1;
 196 }
 197
 198 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 199 {
 200         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 201                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 202                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 203 }
 204
 205 /* For now, we only handle smbus */
 206 static const struct i2c_algorithm i2c_powermac_algorithm = {
 207         .smbus_xfer     = i2c_powermac_smbus_xfer,
 208         .master_xfer    = i2c_powermac_master_xfer,
 209         .functionality  = i2c_powermac_func,
 210 };
 211
 212
 213 static int __devexit i2c_powermac_remove(struct platform_device *dev)
 214 {
 215         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
 216         int                     rc;
 217
 218         rc = i2c_del_adapter(adapter);
 219         /* We aren't that prepared to deal with this... */
 220         if (rc)
 221                 printk(KERN_WARNING
 222                        "i2c-powermac.c: Failed to remove bus %s !\n",
 223                        adapter->name);
 224         platform_set_drvdata(dev, NULL);
 225         memset(adapter, 0, sizeof(*adapter));
 226
 227         return 0;
 228 }
 229
 230
 231 static int __devinit i2c_powermac_probe(struct platform_device *dev)
 232 {
 233         struct pmac_i2c_bus *bus = dev->dev.platform_data;
 234         struct device_node *parent = NULL;
 235         struct i2c_adapter *adapter;
 236         const char *basename;
 237         int rc;
 238
 239         if (bus == NULL)
 240                 return -EINVAL;
 241         adapter = pmac_i2c_get_adapter(bus);
 242
 243         /* Ok, now we need to make up a name for the interface that will
 244          * match what we used to do in the past, that is basically the
 245          * controller's parent device node for keywest. PMU didn't have a
 246          * naming convention and SMU has a different one
 247          */
 248         switch(pmac_i2c_get_type(bus)) {
 249         case pmac_i2c_bus_keywest:
 250                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 251                 if (parent == NULL)
 252                         return -EINVAL;
 253                 basename = parent->name;
 254                 break;
 255         case pmac_i2c_bus_pmu:
 256                 basename = "pmu";
 257                 break;
 258         case pmac_i2c_bus_smu:
 259                 /* This is not what we used to do but I'm fixing drivers at
 260                  * the same time as this change
 261                  */
 262                 basename = "smu";
 263                 break;
 264         default:
 265                 return -EINVAL;
 266         }
 267         snprintf(adapter->name, sizeof(adapter->name), "%s %d", basename,
 268                  pmac_i2c_get_channel(bus));
 269         of_node_put(parent);
 270
 271         platform_set_drvdata(dev, adapter);
 272         adapter->algo = &i2c_powermac_algorithm;
 273         i2c_set_adapdata(adapter, bus);
 274         adapter->dev.parent = &dev->dev;
 275         rc = i2c_add_adapter(adapter);
 276         if (rc) {
 277                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 278                        "failed\n", adapter->name);
 279                 memset(adapter, 0, sizeof(*adapter));
 280         }
 281
 282         printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
 283
 284         if (!strncmp(basename, "uni-n", 5)) {
 285                 struct device_node *np;
 286                 const u32 *prop;
 287                 struct i2c_board_info info;
 288
 289                 /* Instantiate I2C motion sensor if present */
 290                 np = of_find_node_by_name(NULL, "accelerometer");
 291                 if (np && of_device_is_compatible(np, "AAPL,accelerometer_1") &&
 292                     (prop = of_get_property(np, "reg", NULL))) {
 293                         int i2c_bus;
 294                         const char *tmp_bus;
 295
 296                         /* look for bus either using "reg" or by path */
 297                         tmp_bus = strstr(np->full_name, "/i2c-bus@");
 298                         if (tmp_bus)
 299                                 i2c_bus = *(tmp_bus + 9) - '0';
 300                         else
 301                                 i2c_bus = ((*prop) >> 8) & 0x0f;
 302
 303                         if (pmac_i2c_get_channel(bus) == i2c_bus) {
 304                                 memset(&info, 0, sizeof(struct i2c_board_info));
 305                                 info.addr = ((*prop) & 0xff) >> 1;
 306                                 strlcpy(info.type, "ams", I2C_NAME_SIZE);
 307                                 i2c_new_device(adapter, &info);
 308                         }
 309                 }
 310         }
 311
 312         return rc;
 313 }
 314
 315
 316 /* work with hotplug and coldplug */
 317 MODULE_ALIAS("platform:i2c-powermac");
 318
 319 static struct platform_driver i2c_powermac_driver = {
 320         .probe = i2c_powermac_probe,
 321         .remove = __devexit_p(i2c_powermac_remove),
 322         .driver = {
 323                 .name = "i2c-powermac",
 324                 .bus = &platform_bus_type,
 325         },
 326 };
 327
 328 static int __init i2c_powermac_init(void)
 329 {
 330         platform_driver_register(&i2c_powermac_driver);
 331         return 0;
 332 }
 333
 334
 335 static void __exit i2c_powermac_cleanup(void)
 336 {
 337         platform_driver_unregister(&i2c_powermac_driver);
 338 }
 339
 340 module_init(i2c_powermac_init);
 341 module_exit(i2c_powermac_cleanup);