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         u8                      local[2];
  53
  54         rc = pmac_i2c_open(bus, 0);
  55         if (rc)
  56                 return rc;
  57
  58         switch (size) {
  59         case I2C_SMBUS_QUICK:
  60                 rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  61                 if (rc)
  62                         goto bail;
  63                 rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
  64                 break;
  65         case I2C_SMBUS_BYTE:
  66                 rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  67                 if (rc)
  68                         goto bail;
  69                 rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
  70                 break;
  71         case I2C_SMBUS_BYTE_DATA:
  72                 rc = pmac_i2c_setmode(bus, read ?
  73                                       pmac_i2c_mode_combined :
  74                                       pmac_i2c_mode_stdsub);
  75                 if (rc)
  76                         goto bail;
  77                 rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
  78                 break;
  79         case I2C_SMBUS_WORD_DATA:
  80                 rc = pmac_i2c_setmode(bus, read ?
  81                                       pmac_i2c_mode_combined :
  82                                       pmac_i2c_mode_stdsub);
  83                 if (rc)
  84                         goto bail;
  85                 if (!read) {
  86                         local[0] = data->word & 0xff;
  87                         local[1] = (data->word >> 8) & 0xff;
  88                 }
  89                 rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
  90                 if (rc == 0 && read) {
  91                         data->word = ((u16)local[1]) << 8;
  92                         data->word |= local[0];
  93                 }
  94                 break;
  95
  96         /* Note that these are broken vs. the expected smbus API where
  97          * on reads, the length is actually returned from the function,
  98          * but I think the current API makes no sense and I don't want
  99          * any driver that I haven't verified for correctness to go
 100          * anywhere near a pmac i2c bus anyway ...
 101          *
 102          * I'm also not completely sure what kind of phases to do between
 103          * the actual command and the data (what I am _supposed_ to do that
 104          * is). For now, I assume writes are a single stream and reads have
 105          * a repeat start/addr phase (but not stop in between)
 106          */
 107         case I2C_SMBUS_BLOCK_DATA:
 108                 rc = pmac_i2c_setmode(bus, read ?
 109                                       pmac_i2c_mode_combined :
 110                                       pmac_i2c_mode_stdsub);
 111                 if (rc)
 112                         goto bail;
 113                 rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
 114                                    data->block[0] + 1);
 115
 116                 break;
 117         case I2C_SMBUS_I2C_BLOCK_DATA:
 118                 rc = pmac_i2c_setmode(bus, read ?
 119                                       pmac_i2c_mode_combined :
 120                                       pmac_i2c_mode_stdsub);
 121                 if (rc)
 122                         goto bail;
 123                 rc = pmac_i2c_xfer(bus, addrdir, 1, command,
 124                                    &data->block[1], data->block[0]);
 125                 break;
 126
 127         default:
 128                 rc = -EINVAL;
 129         }
 130  bail:
 131         pmac_i2c_close(bus);
 132         return rc;
 133 }
 134
 135 /*
 136  * Generic i2c master transfer entrypoint. This driver only support single
 137  * messages (for "lame i2c" transfers). Anything else should use the smbus
 138  * entry point
 139  */
 140 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
 141                                         struct i2c_msg *msgs,
 142                                         int num)
 143 {
 144         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 145         int                     rc = 0;
 146         int                     read;
 147         int                     addrdir;
 148
 149         if (msgs->flags & I2C_M_TEN)
 150                 return -EINVAL;
 151         read = (msgs->flags & I2C_M_RD) != 0;
 152         addrdir = (msgs->addr << 1) | read;
 153         if (msgs->flags & I2C_M_REV_DIR_ADDR)
 154                 addrdir ^= 1;
 155
 156         rc = pmac_i2c_open(bus, 0);
 157         if (rc)
 158                 return rc;
 159         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 160         if (rc)
 161                 goto bail;
 162         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 163  bail:
 164         pmac_i2c_close(bus);
 165         return rc < 0 ? rc : 1;
 166 }
 167
 168 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 169 {
 170         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 171                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 172                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 173 }
 174
 175 /* For now, we only handle smbus */
 176 static const struct i2c_algorithm i2c_powermac_algorithm = {
 177         .smbus_xfer     = i2c_powermac_smbus_xfer,
 178         .master_xfer    = i2c_powermac_master_xfer,
 179         .functionality  = i2c_powermac_func,
 180 };
 181
 182
 183 static int i2c_powermac_remove(struct platform_device *dev)
 184 {
 185         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
 186         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adapter);
 187         int                     rc;
 188
 189         rc = i2c_del_adapter(adapter);
 190         pmac_i2c_detach_adapter(bus, adapter);
 191         i2c_set_adapdata(adapter, NULL);
 192         /* We aren't that prepared to deal with this... */
 193         if (rc)
 194                 printk("i2c-powermac.c: Failed to remove bus %s !\n",
 195                        adapter->name);
 196         platform_set_drvdata(dev, NULL);
 197         kfree(adapter);
 198
 199         return 0;
 200 }
 201
 202
 203 static int __devexit i2c_powermac_probe(struct platform_device *dev)
 204 {
 205         struct pmac_i2c_bus *bus = dev->dev.platform_data;
 206         struct device_node *parent = NULL;
 207         struct i2c_adapter *adapter;
 208         char name[32];
 209         const char *basename;
 210         int rc;
 211
 212         if (bus == NULL)
 213                 return -EINVAL;
 214
 215         /* Ok, now we need to make up a name for the interface that will
 216          * match what we used to do in the past, that is basically the
 217          * controller's parent device node for keywest. PMU didn't have a
 218          * naming convention and SMU has a different one
 219          */
 220         switch(pmac_i2c_get_type(bus)) {
 221         case pmac_i2c_bus_keywest:
 222                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 223                 if (parent == NULL)
 224                         return -EINVAL;
 225                 basename = parent->name;
 226                 break;
 227         case pmac_i2c_bus_pmu:
 228                 basename = "pmu";
 229                 break;
 230         case pmac_i2c_bus_smu:
 231                 /* This is not what we used to do but I'm fixing drivers at
 232                  * the same time as this change
 233                  */
 234                 basename = "smu";
 235                 break;
 236         default:
 237                 return -EINVAL;
 238         }
 239         snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
 240         of_node_put(parent);
 241
 242         adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 243         if (adapter == NULL) {
 244                 printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
 245                 return -ENOMEM;
 246         }
 247         platform_set_drvdata(dev, adapter);
 248         strcpy(adapter->name, name);
 249         adapter->algo = &i2c_powermac_algorithm;
 250         i2c_set_adapdata(adapter, bus);
 251         adapter->dev.parent = &dev->dev;
 252         pmac_i2c_attach_adapter(bus, adapter);
 253         rc = i2c_add_adapter(adapter);
 254         if (rc) {
 255                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 256                        "failed\n", name);
 257                 i2c_set_adapdata(adapter, NULL);
 258                 pmac_i2c_detach_adapter(bus, adapter);
 259         }
 260
 261         printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
 262         return rc;
 263 }
 264
 265
 266 /* work with hotplug and coldplug */
 267 MODULE_ALIAS("platform:i2c-powermac");
 268
 269 static struct platform_driver i2c_powermac_driver = {
 270         .probe = i2c_powermac_probe,
 271         .remove = __devexit_p(i2c_powermac_remove),
 272         .driver = {
 273                 .name = "i2c-powermac",
 274                 .bus = &platform_bus_type,
 275         },
 276 };
 277
 278 static int __init i2c_powermac_init(void)
 279 {
 280         platform_driver_register(&i2c_powermac_driver);
 281         return 0;
 282 }
 283
 284
 285 static void __exit i2c_powermac_cleanup(void)
 286 {
 287         platform_driver_unregister(&i2c_powermac_driver);
 288 }
 289
 290 module_init(i2c_powermac_init);
 291 module_exit(i2c_powermac_cleanup);