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                 dev_err(&adap->dev,
 126                         "I2C transfer at 0x%02x failed, size %d, err %d\n",
 127                         addrdir >> 1, size, rc);
 128                 goto bail;
 129         }
 130
 131         if (size == I2C_SMBUS_WORD_DATA && read) {
 132                 data->word = ((u16)local[1]) << 8;
 133                 data->word |= local[0];
 134         }
 135
 136  bail:
 137         pmac_i2c_close(bus);
 138         return rc;
 139 }
 140
 141 /*
 142  * Generic i2c master transfer entrypoint. This driver only support single
 143  * messages (for "lame i2c" transfers). Anything else should use the smbus
 144  * entry point
 145  */
 146 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
 147                                         struct i2c_msg *msgs,
 148                                         int num)
 149 {
 150         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 151         int                     rc = 0;
 152         int                     read;
 153         int                     addrdir;
 154
 155         if (num != 1) {
 156                 dev_err(&adap->dev,
 157                         "Multi-message I2C transactions not supported\n");
 158                 return -EOPNOTSUPP;
 159         }
 160
 161         if (msgs->flags & I2C_M_TEN)
 162                 return -EINVAL;
 163         read = (msgs->flags & I2C_M_RD) != 0;
 164         addrdir = (msgs->addr << 1) | read;
 165
 166         rc = pmac_i2c_open(bus, 0);
 167         if (rc) {
 168                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
 169                 return rc;
 170         }
 171         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 172         if (rc) {
 173                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 174                         pmac_i2c_mode_std, rc);
 175                 goto bail;
 176         }
 177         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 178         if (rc < 0)
 179                 dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 180                         addrdir & 1 ? "read from" : "write to", addrdir >> 1,
 181                         rc);
 182  bail:
 183         pmac_i2c_close(bus);
 184         return rc < 0 ? rc : 1;
 185 }
 186
 187 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 188 {
 189         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 190                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 191                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 192 }
 193
 194 /* For now, we only handle smbus */
 195 static const struct i2c_algorithm i2c_powermac_algorithm = {
 196         .smbus_xfer     = i2c_powermac_smbus_xfer,
 197         .master_xfer    = i2c_powermac_master_xfer,
 198         .functionality  = i2c_powermac_func,
 199 };
 200
 201
 202 static int __devexit i2c_powermac_remove(struct platform_device *dev)
 203 {
 204         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
 205         int                     rc;
 206
 207         rc = i2c_del_adapter(adapter);
 208         /* We aren't that prepared to deal with this... */
 209         if (rc)
 210                 printk(KERN_WARNING
 211                        "i2c-powermac.c: Failed to remove bus %s !\n",
 212                        adapter->name);
 213         platform_set_drvdata(dev, NULL);
 214         memset(adapter, 0, sizeof(*adapter));
 215
 216         return 0;
 217 }
 218
 219
 220 static int __devinit i2c_powermac_probe(struct platform_device *dev)
 221 {
 222         struct pmac_i2c_bus *bus = dev->dev.platform_data;
 223         struct device_node *parent = NULL;
 224         struct i2c_adapter *adapter;
 225         const char *basename;
 226         int rc;
 227
 228         if (bus == NULL)
 229                 return -EINVAL;
 230         adapter = pmac_i2c_get_adapter(bus);
 231
 232         /* Ok, now we need to make up a name for the interface that will
 233          * match what we used to do in the past, that is basically the
 234          * controller's parent device node for keywest. PMU didn't have a
 235          * naming convention and SMU has a different one
 236          */
 237         switch(pmac_i2c_get_type(bus)) {
 238         case pmac_i2c_bus_keywest:
 239                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 240                 if (parent == NULL)
 241                         return -EINVAL;
 242                 basename = parent->name;
 243                 break;
 244         case pmac_i2c_bus_pmu:
 245                 basename = "pmu";
 246                 break;
 247         case pmac_i2c_bus_smu:
 248                 /* This is not what we used to do but I'm fixing drivers at
 249                  * the same time as this change
 250                  */
 251                 basename = "smu";
 252                 break;
 253         default:
 254                 return -EINVAL;
 255         }
 256         snprintf(adapter->name, sizeof(adapter->name), "%s %d", basename,
 257                  pmac_i2c_get_channel(bus));
 258         of_node_put(parent);
 259
 260         platform_set_drvdata(dev, adapter);
 261         adapter->algo = &i2c_powermac_algorithm;
 262         i2c_set_adapdata(adapter, bus);
 263         adapter->dev.parent = &dev->dev;
 264         rc = i2c_add_adapter(adapter);
 265         if (rc) {
 266                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 267                        "failed\n", adapter->name);
 268                 memset(adapter, 0, sizeof(*adapter));
 269         }
 270
 271         printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
 272
 273         if (!strncmp(basename, "uni-n", 5)) {
 274                 struct device_node *np;
 275                 const u32 *prop;
 276                 struct i2c_board_info info;
 277
 278                 /* Instantiate I2C motion sensor if present */
 279                 np = of_find_node_by_name(NULL, "accelerometer");
 280                 if (np && of_device_is_compatible(np, "AAPL,accelerometer_1") &&
 281                     (prop = of_get_property(np, "reg", NULL))) {
 282                         int i2c_bus;
 283                         const char *tmp_bus;
 284
 285                         /* look for bus either using "reg" or by path */
 286                         tmp_bus = strstr(np->full_name, "/i2c-bus@");
 287                         if (tmp_bus)
 288                                 i2c_bus = *(tmp_bus + 9) - '0';
 289                         else
 290                                 i2c_bus = ((*prop) >> 8) & 0x0f;
 291
 292                         if (pmac_i2c_get_channel(bus) == i2c_bus) {
 293                                 memset(&info, 0, sizeof(struct i2c_board_info));
 294                                 info.addr = ((*prop) & 0xff) >> 1;
 295                                 strlcpy(info.type, "ams", I2C_NAME_SIZE);
 296                                 i2c_new_device(adapter, &info);
 297                         }
 298                 }
 299         }
 300
 301         return rc;
 302 }
 303
 304
 305 /* work with hotplug and coldplug */
 306 MODULE_ALIAS("platform:i2c-powermac");
 307
 308 static struct platform_driver i2c_powermac_driver = {
 309         .probe = i2c_powermac_probe,
 310         .remove = __devexit_p(i2c_powermac_remove),
 311         .driver = {
 312                 .name = "i2c-powermac",
 313                 .bus = &platform_bus_type,
 314         },
 315 };
 316
 317 static int __init i2c_powermac_init(void)
 318 {
 319         platform_driver_register(&i2c_powermac_driver);
 320         return 0;
 321 }
 322
 323
 324 static void __exit i2c_powermac_cleanup(void)
 325 {
 326         platform_driver_unregister(&i2c_powermac_driver);
 327 }
 328
 329 module_init(i2c_powermac_init);
 330 module_exit(i2c_powermac_cleanup);