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 lenght 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                                    read ? data->block : &data->block[1],
 125                                    data->block[0]);
 126                 break;
 127
 128         default:
 129                 rc = -EINVAL;
 130         }
 131  bail:
 132         pmac_i2c_close(bus);
 133         return rc;
 134 }
 135
 136 /*
 137  * Generic i2c master transfer entrypoint. This driver only support single
 138  * messages (for "lame i2c" transfers). Anything else should use the smbus
 139  * entry point
 140  */
 141 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
 142                                         struct i2c_msg *msgs,
 143                                         int num)
 144 {
 145         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 146         int                     rc = 0;
 147         int                     read;
 148         int                     addrdir;
 149
 150         if (msgs->flags & I2C_M_TEN)
 151                 return -EINVAL;
 152         read = (msgs->flags & I2C_M_RD) != 0;
 153         addrdir = (msgs->addr << 1) | read;
 154         if (msgs->flags & I2C_M_REV_DIR_ADDR)
 155                 addrdir ^= 1;
 156
 157         rc = pmac_i2c_open(bus, 0);
 158         if (rc)
 159                 return rc;
 160         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 161         if (rc)
 162                 goto bail;
 163         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 164  bail:
 165         pmac_i2c_close(bus);
 166         return rc < 0 ? rc : 1;
 167 }
 168
 169 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 170 {
 171         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 172                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 173                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 174 }
 175
 176 /* For now, we only handle smbus */
 177 static const struct i2c_algorithm i2c_powermac_algorithm = {
 178         .smbus_xfer     = i2c_powermac_smbus_xfer,
 179         .master_xfer    = i2c_powermac_master_xfer,
 180         .functionality  = i2c_powermac_func,
 181 };
 182
 183
 184 static int i2c_powermac_remove(struct platform_device *dev)
 185 {
 186         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
 187         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adapter);
 188         int                     rc;
 189
 190         rc = i2c_del_adapter(adapter);
 191         pmac_i2c_detach_adapter(bus, adapter);
 192         i2c_set_adapdata(adapter, NULL);
 193         /* We aren't that prepared to deal with this... */
 194         if (rc)
 195                 printk("i2c-powermac.c: Failed to remove bus %s !\n",
 196                        adapter->name);
 197         platform_set_drvdata(dev, NULL);
 198         kfree(adapter);
 199
 200         return 0;
 201 }
 202
 203
 204 static int __devexit i2c_powermac_probe(struct platform_device *dev)
 205 {
 206         struct pmac_i2c_bus *bus = dev->dev.platform_data;
 207         struct device_node *parent = NULL;
 208         struct i2c_adapter *adapter;
 209         char name[32];
 210         const char *basename;
 211         int rc;
 212
 213         if (bus == NULL)
 214                 return -EINVAL;
 215
 216         /* Ok, now we need to make up a name for the interface that will
 217          * match what we used to do in the past, that is basically the
 218          * controller's parent device node for keywest. PMU didn't have a
 219          * naming convention and SMU has a different one
 220          */
 221         switch(pmac_i2c_get_type(bus)) {
 222         case pmac_i2c_bus_keywest:
 223                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 224                 if (parent == NULL)
 225                         return -EINVAL;
 226                 basename = parent->name;
 227                 break;
 228         case pmac_i2c_bus_pmu:
 229                 basename = "pmu";
 230                 break;
 231         case pmac_i2c_bus_smu:
 232                 /* This is not what we used to do but I'm fixing drivers at
 233                  * the same time as this change
 234                  */
 235                 basename = "smu";
 236                 break;
 237         default:
 238                 return -EINVAL;
 239         }
 240         snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
 241         of_node_put(parent);
 242
 243         adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 244         if (adapter == NULL) {
 245                 printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
 246                 return -ENOMEM;
 247         }
 248         platform_set_drvdata(dev, adapter);
 249         strcpy(adapter->name, name);
 250         adapter->algo = &i2c_powermac_algorithm;
 251         i2c_set_adapdata(adapter, bus);
 252         adapter->dev.parent = &dev->dev;
 253         pmac_i2c_attach_adapter(bus, adapter);
 254         rc = i2c_add_adapter(adapter);
 255         if (rc) {
 256                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 257                        "failed\n", name);
 258                 i2c_set_adapdata(adapter, NULL);
 259                 pmac_i2c_detach_adapter(bus, adapter);
 260         }
 261
 262         printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
 263         return rc;
 264 }
 265
 266
 267 static struct platform_driver i2c_powermac_driver = {
 268         .probe = i2c_powermac_probe,
 269         .remove = __devexit_p(i2c_powermac_remove),
 270         .driver = {
 271                 .name = "i2c-powermac",
 272                 .bus = &platform_bus_type,
 273         },
 274 };
 275
 276 static int __init i2c_powermac_init(void)
 277 {
 278         platform_driver_register(&i2c_powermac_driver);
 279         return 0;
 280 }
 281
 282
 283 static void __exit i2c_powermac_cleanup(void)
 284 {
 285         platform_driver_unregister(&i2c_powermac_driver);
 286 }
 287
 288 module_init(i2c_powermac_init);
 289 module_exit(i2c_powermac_cleanup);