1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 i2c Support for Apple SMU Controller
4
5 Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
6 <benh@kernel.crashing.org>
7
8
9 */
10
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/types.h>
14 #include <linux/i2c.h>
15 #include <linux/device.h>
16 #include <linux/platform_device.h>
17 #include <linux/of_irq.h>
18
19 #include <asm/pmac_low_i2c.h>
20
21 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
22 MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
23 MODULE_LICENSE("GPL");
24
25 /*
26 * SMBUS-type transfer entrypoint
27 */
i2c_powermac_smbus_xfer(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)28 static s32 i2c_powermac_smbus_xfer( struct i2c_adapter* adap,
29 u16 addr,
30 unsigned short flags,
31 char read_write,
32 u8 command,
33 int size,
34 union i2c_smbus_data* data)
35 {
36 struct pmac_i2c_bus *bus = i2c_get_adapdata(adap);
37 int rc = 0;
38 int read = (read_write == I2C_SMBUS_READ);
39 int addrdir = (addr << 1) | read;
40 int mode, subsize, len;
41 u32 subaddr;
42 u8 *buf;
43 u8 local[2];
44
45 if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) {
46 mode = pmac_i2c_mode_std;
47 subsize = 0;
48 subaddr = 0;
49 } else {
50 mode = read ? pmac_i2c_mode_combined : pmac_i2c_mode_stdsub;
51 subsize = 1;
52 subaddr = command;
53 }
54
55 switch (size) {
56 case I2C_SMBUS_QUICK:
57 buf = NULL;
58 len = 0;
59 break;
60 case I2C_SMBUS_BYTE:
61 case I2C_SMBUS_BYTE_DATA:
62 buf = &data->byte;
63 len = 1;
64 break;
65 case I2C_SMBUS_WORD_DATA:
66 if (!read) {
67 local[0] = data->word & 0xff;
68 local[1] = (data->word >> 8) & 0xff;
69 }
70 buf = local;
71 len = 2;
72 break;
73
74 /* Note that these are broken vs. the expected smbus API where
75 * on reads, the length is actually returned from the function,
76 * but I think the current API makes no sense and I don't want
77 * any driver that I haven't verified for correctness to go
78 * anywhere near a pmac i2c bus anyway ...
79 */
80 case I2C_SMBUS_BLOCK_DATA:
81 buf = data->block;
82 len = data->block[0] + 1;
83 break;
84 case I2C_SMBUS_I2C_BLOCK_DATA:
85 buf = &data->block[1];
86 len = data->block[0];
87 break;
88
89 default:
90 return -EINVAL;
91 }
92
93 rc = pmac_i2c_open(bus, 0);
94 if (rc) {
95 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
96 return rc;
97 }
98
99 rc = pmac_i2c_setmode(bus, mode);
100 if (rc) {
101 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
102 mode, rc);
103 goto bail;
104 }
105
106 rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
107 if (rc) {
108 if (rc == -ENXIO)
109 dev_dbg(&adap->dev,
110 "I2C transfer at 0x%02x failed, size %d, "
111 "err %d\n", addrdir >> 1, size, rc);
112 else
113 dev_err(&adap->dev,
114 "I2C transfer at 0x%02x failed, size %d, "
115 "err %d\n", addrdir >> 1, size, rc);
116 goto bail;
117 }
118
119 if (size == I2C_SMBUS_WORD_DATA && read) {
120 data->word = ((u16)local[1]) << 8;
121 data->word |= local[0];
122 }
123
124 bail:
125 pmac_i2c_close(bus);
126 return rc;
127 }
128
129 /*
130 * Generic i2c transfer entrypoint. This driver only supports single
131 * messages (for "lame i2c" transfers). Anything else should use the smbus
132 * entry point
133 */
i2c_powermac_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)134 static int i2c_powermac_xfer(struct i2c_adapter *adap,
135 struct i2c_msg *msgs,
136 int num)
137 {
138 struct pmac_i2c_bus *bus = i2c_get_adapdata(adap);
139 int rc = 0;
140 int addrdir;
141
142 if (msgs->flags & I2C_M_TEN)
143 return -EINVAL;
144 addrdir = i2c_8bit_addr_from_msg(msgs);
145
146 rc = pmac_i2c_open(bus, 0);
147 if (rc) {
148 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
149 return rc;
150 }
151 rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
152 if (rc) {
153 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
154 pmac_i2c_mode_std, rc);
155 goto bail;
156 }
157 rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
158 if (rc < 0) {
159 if (rc == -ENXIO)
160 dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
161 addrdir & 1 ? "read from" : "write to",
162 addrdir >> 1, rc);
163 else
164 dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
165 addrdir & 1 ? "read from" : "write to",
166 addrdir >> 1, rc);
167 }
168 bail:
169 pmac_i2c_close(bus);
170 return rc < 0 ? rc : 1;
171 }
172
i2c_powermac_func(struct i2c_adapter * adapter)173 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
174 {
175 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
176 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
177 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
178 }
179
180 /* For now, we only handle smbus */
181 static const struct i2c_algorithm i2c_powermac_algorithm = {
182 .smbus_xfer = i2c_powermac_smbus_xfer,
183 .xfer = i2c_powermac_xfer,
184 .functionality = i2c_powermac_func,
185 };
186
187 static const struct i2c_adapter_quirks i2c_powermac_quirks = {
188 .max_num_msgs = 1,
189 };
190
i2c_powermac_remove(struct platform_device * dev)191 static void i2c_powermac_remove(struct platform_device *dev)
192 {
193 struct i2c_adapter *adapter = platform_get_drvdata(dev);
194
195 i2c_del_adapter(adapter);
196 memset(adapter, 0, sizeof(*adapter));
197 }
198
i2c_powermac_get_addr(struct i2c_adapter * adap,struct pmac_i2c_bus * bus,struct device_node * node)199 static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
200 struct pmac_i2c_bus *bus,
201 struct device_node *node)
202 {
203 u32 prop;
204 int ret;
205
206 /* First check for valid "reg" */
207 ret = of_property_read_u32(node, "reg", &prop);
208 if (ret == 0)
209 return (prop & 0xff) >> 1;
210
211 /* Then check old-style "i2c-address" */
212 ret = of_property_read_u32(node, "i2c-address", &prop);
213 if (ret == 0)
214 return (prop & 0xff) >> 1;
215
216 /* Now handle some devices with missing "reg" properties */
217 if (of_node_name_eq(node, "cereal"))
218 return 0x60;
219 else if (of_node_name_eq(node, "deq"))
220 return 0x34;
221
222 dev_warn(&adap->dev, "No i2c address for %pOF\n", node);
223
224 return 0xffffffff;
225 }
226
i2c_powermac_create_one(struct i2c_adapter * adap,const char * type,u32 addr)227 static void i2c_powermac_create_one(struct i2c_adapter *adap,
228 const char *type,
229 u32 addr)
230 {
231 struct i2c_board_info info = {};
232 struct i2c_client *newdev;
233
234 strscpy(info.type, type, sizeof(info.type));
235 info.addr = addr;
236 newdev = i2c_new_client_device(adap, &info);
237 if (IS_ERR(newdev))
238 dev_err(&adap->dev,
239 "i2c-powermac: Failure to register missing %s\n",
240 type);
241 }
242
i2c_powermac_add_missing(struct i2c_adapter * adap,struct pmac_i2c_bus * bus,bool found_onyx)243 static void i2c_powermac_add_missing(struct i2c_adapter *adap,
244 struct pmac_i2c_bus *bus,
245 bool found_onyx)
246 {
247 struct device_node *busnode = pmac_i2c_get_bus_node(bus);
248 int rc;
249
250 /* Check for the onyx audio codec */
251 #define ONYX_REG_CONTROL 67
252 if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
253 union i2c_smbus_data data;
254
255 rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
256 ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
257 &data);
258 if (rc >= 0)
259 i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
260
261 rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
262 ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
263 &data);
264 if (rc >= 0)
265 i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
266 }
267 }
268
i2c_powermac_get_type(struct i2c_adapter * adap,struct device_node * node,u32 addr,char * type,int type_size)269 static bool i2c_powermac_get_type(struct i2c_adapter *adap,
270 struct device_node *node,
271 u32 addr, char *type, int type_size)
272 {
273 char tmp[16];
274
275 /*
276 * Note: we do _NOT_ want the standard i2c drivers to match with any of
277 * our powermac stuff unless they have been specifically modified to
278 * handle it on a case by case basis. For example, for thermal control,
279 * things like lm75 etc... shall match with their corresponding
280 * windfarm drivers, _NOT_ the generic ones, so we force a prefix of
281 * 'MAC', onto the modalias to make that happen
282 */
283
284 /* First try proper modalias */
285 if (of_alias_from_compatible(node, tmp, sizeof(tmp)) >= 0) {
286 snprintf(type, type_size, "MAC,%s", tmp);
287 return true;
288 }
289
290 /* Now look for known workarounds */
291 if (of_node_name_eq(node, "deq")) {
292 /* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
293 if (addr == 0x34) {
294 snprintf(type, type_size, "MAC,tas3001");
295 return true;
296 } else if (addr == 0x35) {
297 snprintf(type, type_size, "MAC,tas3004");
298 return true;
299 }
300 }
301
302 dev_err(&adap->dev, "i2c-powermac: modalias failure on %pOF\n", node);
303 return false;
304 }
305
i2c_powermac_register_devices(struct i2c_adapter * adap,struct pmac_i2c_bus * bus)306 static void i2c_powermac_register_devices(struct i2c_adapter *adap,
307 struct pmac_i2c_bus *bus)
308 {
309 struct i2c_client *newdev;
310 struct device_node *node;
311 bool found_onyx = false;
312
313 /*
314 * In some cases we end up with the via-pmu node itself, in this
315 * case we skip this function completely as the device-tree will
316 * not contain anything useful.
317 */
318 if (of_node_name_eq(adap->dev.of_node, "via-pmu"))
319 return;
320
321 for_each_child_of_node(adap->dev.of_node, node) {
322 struct i2c_board_info info = {};
323 u32 addr;
324
325 /* Get address & channel */
326 addr = i2c_powermac_get_addr(adap, bus, node);
327 if (addr == 0xffffffff)
328 continue;
329
330 /* Multibus setup, check channel */
331 if (!pmac_i2c_match_adapter(node, adap))
332 continue;
333
334 dev_dbg(&adap->dev, "i2c-powermac: register %pOF\n", node);
335
336 /*
337 * Keep track of some device existence to handle
338 * workarounds later.
339 */
340 if (of_device_is_compatible(node, "pcm3052"))
341 found_onyx = true;
342
343 /* Make up a modalias */
344 if (!i2c_powermac_get_type(adap, node, addr,
345 info.type, sizeof(info.type))) {
346 continue;
347 }
348
349 /* Fill out the rest of the info structure */
350 info.addr = addr;
351 info.irq = irq_of_parse_and_map(node, 0);
352 info.of_node = of_node_get(node);
353
354 newdev = i2c_new_client_device(adap, &info);
355 if (IS_ERR(newdev)) {
356 dev_err(&adap->dev, "i2c-powermac: Failure to register"
357 " %pOF\n", node);
358 of_node_put(node);
359 /* We do not dispose of the interrupt mapping on
360 * purpose. It's not necessary (interrupt cannot be
361 * re-used) and somebody else might have grabbed it
362 * via direct DT lookup so let's not bother
363 */
364 continue;
365 }
366 }
367
368 /* Additional workarounds */
369 i2c_powermac_add_missing(adap, bus, found_onyx);
370 }
371
i2c_powermac_probe(struct platform_device * dev)372 static int i2c_powermac_probe(struct platform_device *dev)
373 {
374 struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
375 struct device_node *parent;
376 struct i2c_adapter *adapter;
377 int rc;
378
379 if (bus == NULL)
380 return -EINVAL;
381 adapter = pmac_i2c_get_adapter(bus);
382
383 /* Ok, now we need to make up a name for the interface that will
384 * match what we used to do in the past, that is basically the
385 * controller's parent device node for keywest. PMU didn't have a
386 * naming convention and SMU has a different one
387 */
388 switch(pmac_i2c_get_type(bus)) {
389 case pmac_i2c_bus_keywest:
390 parent = of_get_parent(pmac_i2c_get_controller(bus));
391 if (parent == NULL)
392 return -EINVAL;
393 snprintf(adapter->name, sizeof(adapter->name), "%pOFn %d",
394 parent,
395 pmac_i2c_get_channel(bus));
396 of_node_put(parent);
397 break;
398 case pmac_i2c_bus_pmu:
399 snprintf(adapter->name, sizeof(adapter->name), "pmu %d",
400 pmac_i2c_get_channel(bus));
401 break;
402 case pmac_i2c_bus_smu:
403 /* This is not what we used to do but I'm fixing drivers at
404 * the same time as this change
405 */
406 snprintf(adapter->name, sizeof(adapter->name), "smu %d",
407 pmac_i2c_get_channel(bus));
408 break;
409 default:
410 return -EINVAL;
411 }
412
413 platform_set_drvdata(dev, adapter);
414 adapter->algo = &i2c_powermac_algorithm;
415 adapter->quirks = &i2c_powermac_quirks;
416 i2c_set_adapdata(adapter, bus);
417 adapter->dev.parent = &dev->dev;
418
419 /* Clear of_node to skip automatic registration of i2c child nodes */
420 adapter->dev.of_node = NULL;
421 rc = i2c_add_adapter(adapter);
422 if (rc) {
423 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
424 "failed\n", adapter->name);
425 memset(adapter, 0, sizeof(*adapter));
426 return rc;
427 }
428
429 printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
430
431 /* Use custom child registration due to Apple device-tree funkyness */
432 adapter->dev.of_node = dev->dev.of_node;
433 i2c_powermac_register_devices(adapter, bus);
434
435 return 0;
436 }
437
438 static struct platform_driver i2c_powermac_driver = {
439 .probe = i2c_powermac_probe,
440 .remove_new = i2c_powermac_remove,
441 .driver = {
442 .name = "i2c-powermac",
443 .bus = &platform_bus_type,
444 },
445 };
446
447 module_platform_driver(i2c_powermac_driver);
448
449 MODULE_ALIAS("platform:i2c-powermac");
450