drivers/i2c/busses/i2c-pmac-smu.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/config.h>
  24 #include <linux/module.h>
  25 #include <linux/kernel.h>
  26 #include <linux/types.h>
  27 #include <linux/i2c.h>
  28 #include <linux/init.h>
  29 #include <linux/completion.h>
  30 #include <linux/device.h>
  31 #include <asm/prom.h>
  32 #include <asm/of_device.h>
  33 #include <asm/smu.h>
  34
  35 static int probe;
  36
  37 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  38 MODULE_DESCRIPTION("I2C driver for Apple's SMU");
  39 MODULE_LICENSE("GPL");
  40 module_param(probe, bool, 0);
  41
  42
  43 /* Physical interface */
  44 struct smu_iface
  45 {
  46         struct i2c_adapter      adapter;
  47         struct completion       complete;
  48         u32                     busid;
  49 };
  50
  51 static void smu_i2c_done(struct smu_i2c_cmd *cmd, void *misc)
  52 {
  53         struct smu_iface        *iface = misc;
  54         complete(&iface->complete);
  55 }
  56
  57 /*
  58  * SMBUS-type transfer entrypoint
  59  */
  60 static s32 smu_smbus_xfer(      struct i2c_adapter*     adap,
  61                                 u16                     addr,
  62                                 unsigned short          flags,
  63                                 char                    read_write,
  64                                 u8                      command,
  65                                 int                     size,
  66                                 union i2c_smbus_data*   data)
  67 {
  68         struct smu_iface        *iface = i2c_get_adapdata(adap);
  69         struct smu_i2c_cmd      cmd;
  70         int                     rc = 0;
  71         int                     read = (read_write == I2C_SMBUS_READ);
  72
  73         cmd.info.bus = iface->busid;
  74         cmd.info.devaddr = (addr << 1) | (read ? 0x01 : 0x00);
  75
  76         /* Prepare datas & select mode */
  77         switch (size) {
  78         case I2C_SMBUS_QUICK:
  79                 cmd.info.type = SMU_I2C_TRANSFER_SIMPLE;
  80                 cmd.info.datalen = 0;
  81                 break;
  82         case I2C_SMBUS_BYTE:
  83                 cmd.info.type = SMU_I2C_TRANSFER_SIMPLE;
  84                 cmd.info.datalen = 1;
  85                 if (!read)
  86                         cmd.info.data[0] = data->byte;
  87                 break;
  88         case I2C_SMBUS_BYTE_DATA:
  89                 cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
  90                 cmd.info.datalen = 1;
  91                 cmd.info.sublen = 1;
  92                 cmd.info.subaddr[0] = command;
  93                 cmd.info.subaddr[1] = 0;
  94                 cmd.info.subaddr[2] = 0;
  95                 if (!read)
  96                         cmd.info.data[0] = data->byte;
  97                 break;
  98         case I2C_SMBUS_WORD_DATA:
  99                 cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
 100                 cmd.info.datalen = 2;
 101                 cmd.info.sublen = 1;
 102                 cmd.info.subaddr[0] = command;
 103                 cmd.info.subaddr[1] = 0;
 104                 cmd.info.subaddr[2] = 0;
 105                 if (!read) {
 106                         cmd.info.data[0] = data->byte & 0xff;
 107                         cmd.info.data[1] = (data->byte >> 8) & 0xff;
 108                 }
 109                 break;
 110         /* Note that these are broken vs. the expected smbus API where
 111          * on reads, the lenght is actually returned from the function,
 112          * but I think the current API makes no sense and I don't want
 113          * any driver that I haven't verified for correctness to go
 114          * anywhere near a pmac i2c bus anyway ...
 115          */
 116         case I2C_SMBUS_BLOCK_DATA:
 117                 cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
 118                 cmd.info.datalen = data->block[0] + 1;
 119                 if (cmd.info.datalen > 6)
 120                         return -EINVAL;
 121                 if (!read)
 122                         memcpy(cmd.info.data, data->block, cmd.info.datalen);
 123                 cmd.info.sublen = 1;
 124                 cmd.info.subaddr[0] = command;
 125                 cmd.info.subaddr[1] = 0;
 126                 cmd.info.subaddr[2] = 0;
 127                 break;
 128         case I2C_SMBUS_I2C_BLOCK_DATA:
 129                 cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
 130                 cmd.info.datalen = data->block[0];
 131                 if (cmd.info.datalen > 7)
 132                         return -EINVAL;
 133                 if (!read)
 134                         memcpy(cmd.info.data, &data->block[1],
 135                                cmd.info.datalen);
 136                 cmd.info.sublen = 1;
 137                 cmd.info.subaddr[0] = command;
 138                 cmd.info.subaddr[1] = 0;
 139                 cmd.info.subaddr[2] = 0;
 140                 break;
 141
 142         default:
 143                 return -EINVAL;
 144         }
 145
 146         /* Turn a standardsub read into a combined mode access */
 147         if (read_write == I2C_SMBUS_READ &&
 148             cmd.info.type == SMU_I2C_TRANSFER_STDSUB)
 149                 cmd.info.type = SMU_I2C_TRANSFER_COMBINED;
 150
 151         /* Finish filling command and submit it */
 152         cmd.done = smu_i2c_done;
 153         cmd.misc = iface;
 154         rc = smu_queue_i2c(&cmd);
 155         if (rc < 0)
 156                 return rc;
 157         wait_for_completion(&iface->complete);
 158         rc = cmd.status;
 159
 160         if (!read || rc < 0)
 161                 return rc;
 162
 163         switch (size) {
 164         case I2C_SMBUS_BYTE:
 165         case I2C_SMBUS_BYTE_DATA:
 166                 data->byte = cmd.info.data[0];
 167                 break;
 168         case I2C_SMBUS_WORD_DATA:
 169                 data->word = ((u16)cmd.info.data[1]) << 8;
 170                 data->word |= cmd.info.data[0];
 171                 break;
 172         /* Note that these are broken vs. the expected smbus API where
 173          * on reads, the lenght is actually returned from the function,
 174          * but I think the current API makes no sense and I don't want
 175          * any driver that I haven't verified for correctness to go
 176          * anywhere near a pmac i2c bus anyway ...
 177          */
 178         case I2C_SMBUS_BLOCK_DATA:
 179         case I2C_SMBUS_I2C_BLOCK_DATA:
 180                 memcpy(&data->block[0], cmd.info.data, cmd.info.datalen);
 181                 break;
 182         }
 183
 184         return rc;
 185 }
 186
 187 static u32
 188 smu_smbus_func(struct i2c_adapter * adapter)
 189 {
 190         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 191                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 192                I2C_FUNC_SMBUS_BLOCK_DATA;
 193 }
 194
 195 /* For now, we only handle combined mode (smbus) */
 196 static struct i2c_algorithm smu_algorithm = {
 197         .smbus_xfer     = smu_smbus_xfer,
 198         .functionality  = smu_smbus_func,
 199 };
 200
 201 static int create_iface(struct device_node *np, struct device *dev)
 202 {
 203         struct smu_iface* iface;
 204         u32 *reg, busid;
 205         int rc;
 206
 207         reg = (u32 *)get_property(np, "reg", NULL);
 208         if (reg == NULL) {
 209                 printk(KERN_ERR "i2c-pmac-smu: can't find bus number !\n");
 210                 return -ENXIO;
 211         }
 212         busid = *reg;
 213
 214         iface = kmalloc(sizeof(struct smu_iface), GFP_KERNEL);
 215         if (iface == NULL) {
 216                 printk(KERN_ERR "i2c-pmac-smu: can't allocate inteface !\n");
 217                 return -ENOMEM;
 218         }
 219         memset(iface, 0, sizeof(struct smu_iface));
 220         init_completion(&iface->complete);
 221         iface->busid = busid;
 222
 223         dev_set_drvdata(dev, iface);
 224
 225         sprintf(iface->adapter.name, "smu-i2c-%02x", busid);
 226         iface->adapter.algo = &smu_algorithm;
 227         iface->adapter.algo_data = NULL;
 228         iface->adapter.client_register = NULL;
 229         iface->adapter.client_unregister = NULL;
 230         i2c_set_adapdata(&iface->adapter, iface);
 231         iface->adapter.dev.parent = dev;
 232
 233         rc = i2c_add_adapter(&iface->adapter);
 234         if (rc) {
 235                 printk(KERN_ERR "i2c-pamc-smu.c: Adapter %s registration "
 236                        "failed\n", iface->adapter.name);
 237                 i2c_set_adapdata(&iface->adapter, NULL);
 238         }
 239
 240         if (probe) {
 241                 unsigned char addr;
 242                 printk("Probe: ");
 243                 for (addr = 0x00; addr <= 0x7f; addr++) {
 244                         if (i2c_smbus_xfer(&iface->adapter,addr,
 245                                            0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)
 246                                 printk("%02x ", addr);
 247                 }
 248                 printk("\n");
 249         }
 250
 251         printk(KERN_INFO "SMU i2c bus %x registered\n", busid);
 252
 253         return 0;
 254 }
 255
 256 static int dispose_iface(struct device *dev)
 257 {
 258         struct smu_iface *iface = dev_get_drvdata(dev);
 259         int rc;
 260
 261         rc = i2c_del_adapter(&iface->adapter);
 262         i2c_set_adapdata(&iface->adapter, NULL);
 263         /* We aren't that prepared to deal with this... */
 264         if (rc)
 265                 printk("i2c-pmac-smu.c: Failed to remove bus %s !\n",
 266                        iface->adapter.name);
 267         dev_set_drvdata(dev, NULL);
 268         kfree(iface);
 269
 270         return 0;
 271 }
 272
 273
 274 static int create_iface_of_platform(struct of_device* dev,
 275                                     const struct of_device_id *match)
 276 {
 277         return create_iface(dev->node, &dev->dev);
 278 }
 279
 280
 281 static int dispose_iface_of_platform(struct of_device* dev)
 282 {
 283         return dispose_iface(&dev->dev);
 284 }
 285
 286
 287 static struct of_device_id i2c_smu_match[] =
 288 {
 289         {
 290                 .compatible     = "smu-i2c",
 291         },
 292         {},
 293 };
 294 static struct of_platform_driver i2c_smu_of_platform_driver =
 295 {
 296         .name           = "i2c-smu",
 297         .match_table    = i2c_smu_match,
 298         .probe          = create_iface_of_platform,
 299         .remove         = dispose_iface_of_platform
 300 };
 301
 302
 303 static int __init i2c_pmac_smu_init(void)
 304 {
 305         of_register_driver(&i2c_smu_of_platform_driver);
 306         return 0;
 307 }
 308
 309
 310 static void __exit i2c_pmac_smu_cleanup(void)
 311 {
 312         of_unregister_driver(&i2c_smu_of_platform_driver);
 313 }
 314
 315 module_init(i2c_pmac_smu_init);
 316 module_exit(i2c_pmac_smu_cleanup);