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Linux/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 */
 18 
 19 #include <linux/module.h>
 20 #include <linux/kernel.h>
 21 #include <linux/types.h>
 22 #include <linux/i2c.h>
 23 #include <linux/device.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/of_irq.h>
 26 #include <asm/prom.h>
 27 #include <asm/pmac_low_i2c.h>
 28 
 29 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 30 MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
 31 MODULE_LICENSE("GPL");
 32 
 33 /*
 34  * SMBUS-type transfer entrypoint
 35  */
 36 static s32 i2c_powermac_smbus_xfer(     struct i2c_adapter*     adap,
 37                                         u16                     addr,
 38                                         unsigned short          flags,
 39                                         char                    read_write,
 40                                         u8                      command,
 41                                         int                     size,
 42                                         union i2c_smbus_data*   data)
 43 {
 44         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 45         int                     rc = 0;
 46         int                     read = (read_write == I2C_SMBUS_READ);
 47         int                     addrdir = (addr << 1) | read;
 48         int                     mode, subsize, len;
 49         u32                     subaddr;
 50         u8                      *buf;
 51         u8                      local[2];
 52 
 53         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) {
 54                 mode = pmac_i2c_mode_std;
 55                 subsize = 0;
 56                 subaddr = 0;
 57         } else {
 58                 mode = read ? pmac_i2c_mode_combined : pmac_i2c_mode_stdsub;
 59                 subsize = 1;
 60                 subaddr = command;
 61         }
 62 
 63         switch (size) {
 64         case I2C_SMBUS_QUICK:
 65                 buf = NULL;
 66                 len = 0;
 67                 break;
 68         case I2C_SMBUS_BYTE:
 69         case I2C_SMBUS_BYTE_DATA:
 70                 buf = &data->byte;
 71                 len = 1;
 72                 break;
 73         case I2C_SMBUS_WORD_DATA:
 74                 if (!read) {
 75                         local[0] = data->word & 0xff;
 76                         local[1] = (data->word >> 8) & 0xff;
 77                 }
 78                 buf = local;
 79                 len = 2;
 80                 break;
 81 
 82         /* Note that these are broken vs. the expected smbus API where
 83          * on reads, the length is actually returned from the function,
 84          * but I think the current API makes no sense and I don't want
 85          * any driver that I haven't verified for correctness to go
 86          * anywhere near a pmac i2c bus anyway ...
 87          *
 88          * I'm also not completely sure what kind of phases to do between
 89          * the actual command and the data (what I am _supposed_ to do that
 90          * is). For now, I assume writes are a single stream and reads have
 91          * a repeat start/addr phase (but not stop in between)
 92          */
 93         case I2C_SMBUS_BLOCK_DATA:
 94                 buf = data->block;
 95                 len = data->block[0] + 1;
 96                 break;
 97         case I2C_SMBUS_I2C_BLOCK_DATA:
 98                 buf = &data->block[1];
 99                 len = data->block[0];
100                 break;
101 
102         default:
103                 return -EINVAL;
104         }
105 
106         rc = pmac_i2c_open(bus, 0);
107         if (rc) {
108                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
109                 return rc;
110         }
111 
112         rc = pmac_i2c_setmode(bus, mode);
113         if (rc) {
114                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
115                         mode, rc);
116                 goto bail;
117         }
118 
119         rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
120         if (rc) {
121                 if (rc == -ENXIO)
122                         dev_dbg(&adap->dev,
123                                 "I2C transfer at 0x%02x failed, size %d, "
124                                 "err %d\n", addrdir >> 1, size, rc);
125                 else
126                         dev_err(&adap->dev,
127                                 "I2C transfer at 0x%02x failed, size %d, "
128                                 "err %d\n", addrdir >> 1, size, rc);
129                 goto bail;
130         }
131 
132         if (size == I2C_SMBUS_WORD_DATA && read) {
133                 data->word = ((u16)local[1]) << 8;
134                 data->word |= local[0];
135         }
136 
137  bail:
138         pmac_i2c_close(bus);
139         return rc;
140 }
141 
142 /*
143  * Generic i2c master transfer entrypoint. This driver only support single
144  * messages (for "lame i2c" transfers). Anything else should use the smbus
145  * entry point
146  */
147 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
148                                         struct i2c_msg *msgs,
149                                         int num)
150 {
151         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
152         int                     rc = 0;
153         int                     read;
154         int                     addrdir;
155 
156         if (num != 1) {
157                 dev_err(&adap->dev,
158                         "Multi-message I2C transactions not supported\n");
159                 return -EOPNOTSUPP;
160         }
161 
162         if (msgs->flags & I2C_M_TEN)
163                 return -EINVAL;
164         read = (msgs->flags & I2C_M_RD) != 0;
165         addrdir = (msgs->addr << 1) | read;
166 
167         rc = pmac_i2c_open(bus, 0);
168         if (rc) {
169                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
170                 return rc;
171         }
172         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
173         if (rc) {
174                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
175                         pmac_i2c_mode_std, rc);
176                 goto bail;
177         }
178         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
179         if (rc < 0) {
180                 if (rc == -ENXIO)
181                         dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
182                                 addrdir & 1 ? "read from" : "write to",
183                                 addrdir >> 1, rc);
184                 else
185                         dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
186                                 addrdir & 1 ? "read from" : "write to",
187                                 addrdir >> 1, rc);
188         }
189  bail:
190         pmac_i2c_close(bus);
191         return rc < 0 ? rc : 1;
192 }
193 
194 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
195 {
196         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
197                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
198                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
199 }
200 
201 /* For now, we only handle smbus */
202 static const struct i2c_algorithm i2c_powermac_algorithm = {
203         .smbus_xfer     = i2c_powermac_smbus_xfer,
204         .master_xfer    = i2c_powermac_master_xfer,
205         .functionality  = i2c_powermac_func,
206 };
207 
208 
209 static int i2c_powermac_remove(struct platform_device *dev)
210 {
211         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
212 
213         i2c_del_adapter(adapter);
214         memset(adapter, 0, sizeof(*adapter));
215 
216         return 0;
217 }
218 
219 static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
220                                            struct pmac_i2c_bus *bus,
221                                            struct device_node *node)
222 {
223         const __be32 *prop;
224         int len;
225 
226         /* First check for valid "reg" */
227         prop = of_get_property(node, "reg", &len);
228         if (prop && (len >= sizeof(int)))
229                 return (be32_to_cpup(prop) & 0xff) >> 1;
230 
231         /* Then check old-style "i2c-address" */
232         prop = of_get_property(node, "i2c-address", &len);
233         if (prop && (len >= sizeof(int)))
234                 return (be32_to_cpup(prop) & 0xff) >> 1;
235 
236         /* Now handle some devices with missing "reg" properties */
237         if (!strcmp(node->name, "cereal"))
238                 return 0x60;
239         else if (!strcmp(node->name, "deq"))
240                 return 0x34;
241 
242         dev_warn(&adap->dev, "No i2c address for %s\n", node->full_name);
243 
244         return 0xffffffff;
245 }
246 
247 static void i2c_powermac_create_one(struct i2c_adapter *adap,
248                                               const char *type,
249                                               u32 addr)
250 {
251         struct i2c_board_info info = {};
252         struct i2c_client *newdev;
253 
254         strncpy(info.type, type, sizeof(info.type));
255         info.addr = addr;
256         newdev = i2c_new_device(adap, &info);
257         if (!newdev)
258                 dev_err(&adap->dev,
259                         "i2c-powermac: Failure to register missing %s\n",
260                         type);
261 }
262 
263 static void i2c_powermac_add_missing(struct i2c_adapter *adap,
264                                                struct pmac_i2c_bus *bus,
265                                                bool found_onyx)
266 {
267         struct device_node *busnode = pmac_i2c_get_bus_node(bus);
268         int rc;
269 
270         /* Check for the onyx audio codec */
271 #define ONYX_REG_CONTROL                67
272         if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
273                 union i2c_smbus_data data;
274 
275                 rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
276                                     ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
277                                     &data);
278                 if (rc >= 0)
279                         i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
280 
281                 rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
282                                     ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
283                                     &data);
284                 if (rc >= 0)
285                         i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
286         }
287 }
288 
289 static bool i2c_powermac_get_type(struct i2c_adapter *adap,
290                                             struct device_node *node,
291                                             u32 addr, char *type, int type_size)
292 {
293         char tmp[16];
294 
295         /* Note: we to _NOT_ want the standard
296          * i2c drivers to match with any of our powermac stuff
297          * unless they have been specifically modified to handle
298          * it on a case by case basis. For example, for thermal
299          * control, things like lm75 etc... shall match with their
300          * corresponding windfarm drivers, _NOT_ the generic ones,
301          * so we force a prefix of AAPL, onto the modalias to
302          * make that happen
303          */
304 
305         /* First try proper modalias */
306         if (of_modalias_node(node, tmp, sizeof(tmp)) >= 0) {
307                 snprintf(type, type_size, "MAC,%s", tmp);
308                 return true;
309         }
310 
311         /* Now look for known workarounds */
312         if (!strcmp(node->name, "deq")) {
313                 /* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
314                 if (addr == 0x34) {
315                         snprintf(type, type_size, "MAC,tas3001");
316                         return true;
317                 } else if (addr == 0x35) {
318                         snprintf(type, type_size, "MAC,tas3004");
319                         return true;
320                 }
321         }
322 
323         dev_err(&adap->dev, "i2c-powermac: modalias failure"
324                 " on %s\n", node->full_name);
325         return false;
326 }
327 
328 static void i2c_powermac_register_devices(struct i2c_adapter *adap,
329                                                     struct pmac_i2c_bus *bus)
330 {
331         struct i2c_client *newdev;
332         struct device_node *node;
333         bool found_onyx = 0;
334 
335         /*
336          * In some cases we end up with the via-pmu node itself, in this
337          * case we skip this function completely as the device-tree will
338          * not contain anything useful.
339          */
340         if (!strcmp(adap->dev.of_node->name, "via-pmu"))
341                 return;
342 
343         for_each_child_of_node(adap->dev.of_node, node) {
344                 struct i2c_board_info info = {};
345                 u32 addr;
346 
347                 /* Get address & channel */
348                 addr = i2c_powermac_get_addr(adap, bus, node);
349                 if (addr == 0xffffffff)
350                         continue;
351 
352                 /* Multibus setup, check channel */
353                 if (!pmac_i2c_match_adapter(node, adap))
354                         continue;
355 
356                 dev_dbg(&adap->dev, "i2c-powermac: register %s\n",
357                         node->full_name);
358 
359                 /*
360                  * Keep track of some device existence to handle
361                  * workarounds later.
362                  */
363                 if (of_device_is_compatible(node, "pcm3052"))
364                         found_onyx = true;
365 
366                 /* Make up a modalias */
367                 if (!i2c_powermac_get_type(adap, node, addr,
368                                            info.type, sizeof(info.type))) {
369                         continue;
370                 }
371 
372                 /* Fill out the rest of the info structure */
373                 info.addr = addr;
374                 info.irq = irq_of_parse_and_map(node, 0);
375                 info.of_node = of_node_get(node);
376 
377                 newdev = i2c_new_device(adap, &info);
378                 if (!newdev) {
379                         dev_err(&adap->dev, "i2c-powermac: Failure to register"
380                                 " %s\n", node->full_name);
381                         of_node_put(node);
382                         /* We do not dispose of the interrupt mapping on
383                          * purpose. It's not necessary (interrupt cannot be
384                          * re-used) and somebody else might have grabbed it
385                          * via direct DT lookup so let's not bother
386                          */
387                         continue;
388                 }
389         }
390 
391         /* Additional workarounds */
392         i2c_powermac_add_missing(adap, bus, found_onyx);
393 }
394 
395 static int i2c_powermac_probe(struct platform_device *dev)
396 {
397         struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
398         struct device_node *parent = NULL;
399         struct i2c_adapter *adapter;
400         const char *basename;
401         int rc;
402 
403         if (bus == NULL)
404                 return -EINVAL;
405         adapter = pmac_i2c_get_adapter(bus);
406 
407         /* Ok, now we need to make up a name for the interface that will
408          * match what we used to do in the past, that is basically the
409          * controller's parent device node for keywest. PMU didn't have a
410          * naming convention and SMU has a different one
411          */
412         switch(pmac_i2c_get_type(bus)) {
413         case pmac_i2c_bus_keywest:
414                 parent = of_get_parent(pmac_i2c_get_controller(bus));
415                 if (parent == NULL)
416                         return -EINVAL;
417                 basename = parent->name;
418                 break;
419         case pmac_i2c_bus_pmu:
420                 basename = "pmu";
421                 break;
422         case pmac_i2c_bus_smu:
423                 /* This is not what we used to do but I'm fixing drivers at
424                  * the same time as this change
425                  */
426                 basename = "smu";
427                 break;
428         default:
429                 return -EINVAL;
430         }
431         snprintf(adapter->name, sizeof(adapter->name), "%s %d", basename,
432                  pmac_i2c_get_channel(bus));
433         of_node_put(parent);
434 
435         platform_set_drvdata(dev, adapter);
436         adapter->algo = &i2c_powermac_algorithm;
437         i2c_set_adapdata(adapter, bus);
438         adapter->dev.parent = &dev->dev;
439 
440         /* Clear of_node to skip automatic registration of i2c child nodes */
441         adapter->dev.of_node = NULL;
442         rc = i2c_add_adapter(adapter);
443         if (rc) {
444                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
445                        "failed\n", adapter->name);
446                 memset(adapter, 0, sizeof(*adapter));
447                 return rc;
448         }
449 
450         printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
451 
452         /* Use custom child registration due to Apple device-tree funkyness */
453         adapter->dev.of_node = dev->dev.of_node;
454         i2c_powermac_register_devices(adapter, bus);
455 
456         return 0;
457 }
458 
459 static struct platform_driver i2c_powermac_driver = {
460         .probe = i2c_powermac_probe,
461         .remove = i2c_powermac_remove,
462         .driver = {
463                 .name = "i2c-powermac",
464                 .bus = &platform_bus_type,
465         },
466 };
467 
468 module_platform_driver(i2c_powermac_driver);
469 
470 MODULE_ALIAS("platform:i2c-powermac");
471 

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