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			addrdir;
154 
155 	if (msgs->flags & I2C_M_TEN)
156 		return -EINVAL;
157 	addrdir = i2c_8bit_addr_from_msg(msgs);
158 
159 	rc = pmac_i2c_open(bus, 0);
160 	if (rc) {
161 		dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
162 		return rc;
163 	}
164 	rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
165 	if (rc) {
166 		dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
167 			pmac_i2c_mode_std, rc);
168 		goto bail;
169 	}
170 	rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
171 	if (rc < 0) {
172 		if (rc == -ENXIO)
173 			dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
174 				addrdir & 1 ? "read from" : "write to",
175 				addrdir >> 1, rc);
176 		else
177 			dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
178 				addrdir & 1 ? "read from" : "write to",
179 				addrdir >> 1, rc);
180 	}
181  bail:
182 	pmac_i2c_close(bus);
183 	return rc < 0 ? rc : 1;
184 }
185 
186 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
187 {
188 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
189 		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
190 		I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
191 }
192 
193 /* For now, we only handle smbus */
194 static const struct i2c_algorithm i2c_powermac_algorithm = {
195 	.smbus_xfer	= i2c_powermac_smbus_xfer,
196 	.master_xfer	= i2c_powermac_master_xfer,
197 	.functionality	= i2c_powermac_func,
198 };
199 
200 static const struct i2c_adapter_quirks i2c_powermac_quirks = {
201 	.max_num_msgs = 1,
202 };
203 
204 static int i2c_powermac_remove(struct platform_device *dev)
205 {
206 	struct i2c_adapter	*adapter = platform_get_drvdata(dev);
207 
208 	i2c_del_adapter(adapter);
209 	memset(adapter, 0, sizeof(*adapter));
210 
211 	return 0;
212 }
213 
214 static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
215 					   struct pmac_i2c_bus *bus,
216 					   struct device_node *node)
217 {
218 	const __be32 *prop;
219 	int len;
220 
221 	/* First check for valid "reg" */
222 	prop = of_get_property(node, "reg", &len);
223 	if (prop && (len >= sizeof(int)))
224 		return (be32_to_cpup(prop) & 0xff) >> 1;
225 
226 	/* Then check old-style "i2c-address" */
227 	prop = of_get_property(node, "i2c-address", &len);
228 	if (prop && (len >= sizeof(int)))
229 		return (be32_to_cpup(prop) & 0xff) >> 1;
230 
231 	/* Now handle some devices with missing "reg" properties */
232 	if (!strcmp(node->name, "cereal"))
233 		return 0x60;
234 	else if (!strcmp(node->name, "deq"))
235 		return 0x34;
236 
237 	dev_warn(&adap->dev, "No i2c address for %pOF\n", node);
238 
239 	return 0xffffffff;
240 }
241 
242 static void i2c_powermac_create_one(struct i2c_adapter *adap,
243 					      const char *type,
244 					      u32 addr)
245 {
246 	struct i2c_board_info info = {};
247 	struct i2c_client *newdev;
248 
249 	strncpy(info.type, type, sizeof(info.type));
250 	info.addr = addr;
251 	newdev = i2c_new_device(adap, &info);
252 	if (!newdev)
253 		dev_err(&adap->dev,
254 			"i2c-powermac: Failure to register missing %s\n",
255 			type);
256 }
257 
258 static void i2c_powermac_add_missing(struct i2c_adapter *adap,
259 					       struct pmac_i2c_bus *bus,
260 					       bool found_onyx)
261 {
262 	struct device_node *busnode = pmac_i2c_get_bus_node(bus);
263 	int rc;
264 
265 	/* Check for the onyx audio codec */
266 #define ONYX_REG_CONTROL		67
267 	if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
268 		union i2c_smbus_data data;
269 
270 		rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
271 				    ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
272 				    &data);
273 		if (rc >= 0)
274 			i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
275 
276 		rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
277 				    ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
278 				    &data);
279 		if (rc >= 0)
280 			i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
281 	}
282 }
283 
284 static bool i2c_powermac_get_type(struct i2c_adapter *adap,
285 					    struct device_node *node,
286 					    u32 addr, char *type, int type_size)
287 {
288 	char tmp[16];
289 
290 	/* Note: we to _NOT_ want the standard
291 	 * i2c drivers to match with any of our powermac stuff
292 	 * unless they have been specifically modified to handle
293 	 * it on a case by case basis. For example, for thermal
294 	 * control, things like lm75 etc... shall match with their
295 	 * corresponding windfarm drivers, _NOT_ the generic ones,
296 	 * so we force a prefix of AAPL, onto the modalias to
297 	 * make that happen
298 	 */
299 
300 	/* First try proper modalias */
301 	if (of_modalias_node(node, tmp, sizeof(tmp)) >= 0) {
302 		snprintf(type, type_size, "MAC,%s", tmp);
303 		return true;
304 	}
305 
306 	/* Now look for known workarounds */
307 	if (!strcmp(node->name, "deq")) {
308 		/* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
309 		if (addr == 0x34) {
310 			snprintf(type, type_size, "MAC,tas3001");
311 			return true;
312 		} else if (addr == 0x35) {
313 			snprintf(type, type_size, "MAC,tas3004");
314 			return true;
315 		}
316 	}
317 
318 	dev_err(&adap->dev, "i2c-powermac: modalias failure on %pOF\n", node);
319 	return false;
320 }
321 
322 static void i2c_powermac_register_devices(struct i2c_adapter *adap,
323 						    struct pmac_i2c_bus *bus)
324 {
325 	struct i2c_client *newdev;
326 	struct device_node *node;
327 	bool found_onyx = 0;
328 
329 	/*
330 	 * In some cases we end up with the via-pmu node itself, in this
331 	 * case we skip this function completely as the device-tree will
332 	 * not contain anything useful.
333 	 */
334 	if (!strcmp(adap->dev.of_node->name, "via-pmu"))
335 		return;
336 
337 	for_each_child_of_node(adap->dev.of_node, node) {
338 		struct i2c_board_info info = {};
339 		u32 addr;
340 
341 		/* Get address & channel */
342 		addr = i2c_powermac_get_addr(adap, bus, node);
343 		if (addr == 0xffffffff)
344 			continue;
345 
346 		/* Multibus setup, check channel */
347 		if (!pmac_i2c_match_adapter(node, adap))
348 			continue;
349 
350 		dev_dbg(&adap->dev, "i2c-powermac: register %pOF\n", node);
351 
352 		/*
353 		 * Keep track of some device existence to handle
354 		 * workarounds later.
355 		 */
356 		if (of_device_is_compatible(node, "pcm3052"))
357 			found_onyx = true;
358 
359 		/* Make up a modalias */
360 		if (!i2c_powermac_get_type(adap, node, addr,
361 					   info.type, sizeof(info.type))) {
362 			continue;
363 		}
364 
365 		/* Fill out the rest of the info structure */
366 		info.addr = addr;
367 		info.irq = irq_of_parse_and_map(node, 0);
368 		info.of_node = of_node_get(node);
369 
370 		newdev = i2c_new_device(adap, &info);
371 		if (!newdev) {
372 			dev_err(&adap->dev, "i2c-powermac: Failure to register"
373 				" %pOF\n", node);
374 			of_node_put(node);
375 			/* We do not dispose of the interrupt mapping on
376 			 * purpose. It's not necessary (interrupt cannot be
377 			 * re-used) and somebody else might have grabbed it
378 			 * via direct DT lookup so let's not bother
379 			 */
380 			continue;
381 		}
382 	}
383 
384 	/* Additional workarounds */
385 	i2c_powermac_add_missing(adap, bus, found_onyx);
386 }
387 
388 static int i2c_powermac_probe(struct platform_device *dev)
389 {
390 	struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
391 	struct device_node *parent = NULL;
392 	struct i2c_adapter *adapter;
393 	const char *basename;
394 	int rc;
395 
396 	if (bus == NULL)
397 		return -EINVAL;
398 	adapter = pmac_i2c_get_adapter(bus);
399 
400 	/* Ok, now we need to make up a name for the interface that will
401 	 * match what we used to do in the past, that is basically the
402 	 * controller's parent device node for keywest. PMU didn't have a
403 	 * naming convention and SMU has a different one
404 	 */
405 	switch(pmac_i2c_get_type(bus)) {
406 	case pmac_i2c_bus_keywest:
407 		parent = of_get_parent(pmac_i2c_get_controller(bus));
408 		if (parent == NULL)
409 			return -EINVAL;
410 		basename = parent->name;
411 		break;
412 	case pmac_i2c_bus_pmu:
413 		basename = "pmu";
414 		break;
415 	case pmac_i2c_bus_smu:
416 		/* This is not what we used to do but I'm fixing drivers at
417 		 * the same time as this change
418 		 */
419 		basename = "smu";
420 		break;
421 	default:
422 		return -EINVAL;
423 	}
424 	snprintf(adapter->name, sizeof(adapter->name), "%s %d", basename,
425 		 pmac_i2c_get_channel(bus));
426 	of_node_put(parent);
427 
428 	platform_set_drvdata(dev, adapter);
429 	adapter->algo = &i2c_powermac_algorithm;
430 	adapter->quirks = &i2c_powermac_quirks;
431 	i2c_set_adapdata(adapter, bus);
432 	adapter->dev.parent = &dev->dev;
433 
434 	/* Clear of_node to skip automatic registration of i2c child nodes */
435 	adapter->dev.of_node = NULL;
436 	rc = i2c_add_adapter(adapter);
437 	if (rc) {
438 		printk(KERN_ERR "i2c-powermac: Adapter %s registration "
439 		       "failed\n", adapter->name);
440 		memset(adapter, 0, sizeof(*adapter));
441 		return rc;
442 	}
443 
444 	printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
445 
446 	/* Use custom child registration due to Apple device-tree funkyness */
447 	adapter->dev.of_node = dev->dev.of_node;
448 	i2c_powermac_register_devices(adapter, bus);
449 
450 	return 0;
451 }
452 
453 static struct platform_driver i2c_powermac_driver = {
454 	.probe = i2c_powermac_probe,
455 	.remove = i2c_powermac_remove,
456 	.driver = {
457 		.name = "i2c-powermac",
458 		.bus = &platform_bus_type,
459 	},
460 };
461 
462 module_platform_driver(i2c_powermac_driver);
463 
464 MODULE_ALIAS("platform:i2c-powermac");
465