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/completion.h>
  29 #include <linux/device.h>
  30 #include <linux/platform_device.h>
  31 #include <asm/prom.h>
  32 #include <asm/pmac_low_i2c.h>
  33
  34 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  35 MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
  36 MODULE_LICENSE("GPL");
  37
  38 /*
  39  * SMBUS-type transfer entrypoint
  40  */
  41 static s32 i2c_powermac_smbus_xfer(     struct i2c_adapter*     adap,
  42                                         u16                     addr,
  43                                         unsigned short          flags,
  44                                         char                    read_write,
  45                                         u8                      command,
  46                                         int                     size,
  47                                         union i2c_smbus_data*   data)
  48 {
  49         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
  50         int                     rc = 0;
  51         int                     read = (read_write == I2C_SMBUS_READ);
  52         int                     addrdir = (addr << 1) | read;
  53         u8                      local[2];
  54
  55         rc = pmac_i2c_open(bus, 0);
  56         if (rc)
  57                 return rc;
  58
  59         switch (size) {
  60         case I2C_SMBUS_QUICK:
  61                 rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  62                 if (rc)
  63                         goto bail;
  64                 rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
  65                 break;
  66         case I2C_SMBUS_BYTE:
  67                 rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  68                 if (rc)
  69                         goto bail;
  70                 rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
  71                 break;
  72         case I2C_SMBUS_BYTE_DATA:
  73                 rc = pmac_i2c_setmode(bus, read ?
  74                                       pmac_i2c_mode_combined :
  75                                       pmac_i2c_mode_stdsub);
  76                 if (rc)
  77                         goto bail;
  78                 rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
  79                 break;
  80         case I2C_SMBUS_WORD_DATA:
  81                 rc = pmac_i2c_setmode(bus, read ?
  82                                       pmac_i2c_mode_combined :
  83                                       pmac_i2c_mode_stdsub);
  84                 if (rc)
  85                         goto bail;
  86                 if (!read) {
  87                         local[0] = data->word & 0xff;
  88                         local[1] = (data->word >> 8) & 0xff;
  89                 }
  90                 rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
  91                 if (rc == 0 && read) {
  92                         data->word = ((u16)local[1]) << 8;
  93                         data->word |= local[0];
  94                 }
  95                 break;
  96
  97         /* Note that these are broken vs. the expected smbus API where
  98          * on reads, the lenght is actually returned from the function,
  99          * but I think the current API makes no sense and I don't want
 100          * any driver that I haven't verified for correctness to go
 101          * anywhere near a pmac i2c bus anyway ...
 102          *
 103          * I'm also not completely sure what kind of phases to do between
 104          * the actual command and the data (what I am _supposed_ to do that
 105          * is). For now, I assume writes are a single stream and reads have
 106          * a repeat start/addr phase (but not stop in between)
 107          */
 108         case I2C_SMBUS_BLOCK_DATA:
 109                 rc = pmac_i2c_setmode(bus, read ?
 110                                       pmac_i2c_mode_combined :
 111                                       pmac_i2c_mode_stdsub);
 112                 if (rc)
 113                         goto bail;
 114                 rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
 115                                    data->block[0] + 1);
 116
 117                 break;
 118         case I2C_SMBUS_I2C_BLOCK_DATA:
 119                 rc = pmac_i2c_setmode(bus, read ?
 120                                       pmac_i2c_mode_combined :
 121                                       pmac_i2c_mode_stdsub);
 122                 if (rc)
 123                         goto bail;
 124                 rc = pmac_i2c_xfer(bus, addrdir, 1, command,
 125                                    read ? data->block : &data->block[1],
 126                                    data->block[0]);
 127                 break;
 128
 129         default:
 130                 rc = -EINVAL;
 131         }
 132  bail:
 133         pmac_i2c_close(bus);
 134         return rc;
 135 }
 136
 137 /*
 138  * Generic i2c master transfer entrypoint. This driver only support single
 139  * messages (for "lame i2c" transfers). Anything else should use the smbus
 140  * entry point
 141  */
 142 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
 143                                         struct i2c_msg *msgs,
 144                                         int num)
 145 {
 146         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 147         int                     rc = 0;
 148         int                     read;
 149         int                     addrdir;
 150
 151         if (num != 1)
 152                 return -EINVAL;
 153         if (msgs->flags & I2C_M_TEN)
 154                 return -EINVAL;
 155         read = (msgs->flags & I2C_M_RD) != 0;
 156         addrdir = (msgs->addr << 1) | read;
 157         if (msgs->flags & I2C_M_REV_DIR_ADDR)
 158                 addrdir ^= 1;
 159
 160         rc = pmac_i2c_open(bus, 0);
 161         if (rc)
 162                 return rc;
 163         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 164         if (rc)
 165                 goto bail;
 166         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 167  bail:
 168         pmac_i2c_close(bus);
 169         return rc < 0 ? rc : msgs->len;
 170 }
 171
 172 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 173 {
 174         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 175                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 176                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 177 }
 178
 179 /* For now, we only handle smbus */
 180 static struct i2c_algorithm i2c_powermac_algorithm = {
 181         .smbus_xfer     = i2c_powermac_smbus_xfer,
 182         .master_xfer    = i2c_powermac_master_xfer,
 183         .functionality  = i2c_powermac_func,
 184 };
 185
 186
 187 static int i2c_powermac_remove(struct device *dev)
 188 {
 189         struct i2c_adapter      *adapter = dev_get_drvdata(dev);
 190         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adapter);
 191         int                     rc;
 192
 193         rc = i2c_del_adapter(adapter);
 194         pmac_i2c_detach_adapter(bus, adapter);
 195         i2c_set_adapdata(adapter, NULL);
 196         /* We aren't that prepared to deal with this... */
 197         if (rc)
 198                 printk("i2c-powermac.c: Failed to remove bus %s !\n",
 199                        adapter->name);
 200         dev_set_drvdata(dev, NULL);
 201         kfree(adapter);
 202
 203         return 0;
 204 }
 205
 206
 207 static int i2c_powermac_probe(struct device *dev)
 208 {
 209         struct pmac_i2c_bus *bus = dev->platform_data;
 210         struct device_node *parent = NULL;
 211         struct i2c_adapter *adapter;
 212         char name[32];
 213         const char *basename;
 214         int rc;
 215
 216         if (bus == NULL)
 217                 return -EINVAL;
 218
 219         /* Ok, now we need to make up a name for the interface that will
 220          * match what we used to do in the past, that is basically the
 221          * controller's parent device node for keywest. PMU didn't have a
 222          * naming convention and SMU has a different one
 223          */
 224         switch(pmac_i2c_get_type(bus)) {
 225         case pmac_i2c_bus_keywest:
 226                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 227                 if (parent == NULL)
 228                         return -EINVAL;
 229                 basename = parent->name;
 230                 break;
 231         case pmac_i2c_bus_pmu:
 232                 basename = "pmu";
 233                 break;
 234         case pmac_i2c_bus_smu:
 235                 /* This is not what we used to do but I'm fixing drivers at
 236                  * the same time as this change
 237                  */
 238                 basename = "smu";
 239                 break;
 240         default:
 241                 return -EINVAL;
 242         }
 243         snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
 244         of_node_put(parent);
 245
 246         adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 247         if (adapter == NULL) {
 248                 printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
 249                 return -ENOMEM;
 250         }
 251         dev_set_drvdata(dev, adapter);
 252         strcpy(adapter->name, name);
 253         adapter->algo = &i2c_powermac_algorithm;
 254         i2c_set_adapdata(adapter, bus);
 255         adapter->dev.parent = dev;
 256         pmac_i2c_attach_adapter(bus, adapter);
 257         rc = i2c_add_adapter(adapter);
 258         if (rc) {
 259                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 260                        "failed\n", name);
 261                 i2c_set_adapdata(adapter, NULL);
 262                 pmac_i2c_detach_adapter(bus, adapter);
 263         }
 264
 265         printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
 266         return rc;
 267 }
 268
 269
 270 static struct device_driver i2c_powermac_driver = {
 271         .name = "i2c-powermac",
 272         .bus = &platform_bus_type,
 273         .probe = i2c_powermac_probe,
 274         .remove = i2c_powermac_remove,
 275 };
 276
 277 static int __init i2c_powermac_init(void)
 278 {
 279         driver_register(&i2c_powermac_driver);
 280         return 0;
 281 }
 282
 283
 284 static void __exit i2c_powermac_cleanup(void)
 285 {
 286         driver_unregister(&i2c_powermac_driver);
 287 }
 288
 289 module_init(i2c_powermac_init);
 290 module_exit(i2c_powermac_cleanup);