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 #include <asm/prom.h>
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  */
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 	 * I'm also not completely sure what kind of phases to do between
81 	 * the actual command and the data (what I am _supposed_ to do that
82 	 * is). For now, I assume writes are a single stream and reads have
83 	 * a repeat start/addr phase (but not stop in between)
84 	 */
85         case I2C_SMBUS_BLOCK_DATA:
86 		buf = data->block;
87 		len = data->block[0] + 1;
88 		break;
89 	case I2C_SMBUS_I2C_BLOCK_DATA:
90 		buf = &data->block[1];
91 		len = data->block[0];
92 		break;
93 
94         default:
95 		return -EINVAL;
96 	}
97 
98 	rc = pmac_i2c_open(bus, 0);
99 	if (rc) {
100 		dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
101 		return rc;
102 	}
103 
104 	rc = pmac_i2c_setmode(bus, mode);
105 	if (rc) {
106 		dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
107 			mode, rc);
108 		goto bail;
109 	}
110 
111 	rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
112 	if (rc) {
113 		if (rc == -ENXIO)
114 			dev_dbg(&adap->dev,
115 				"I2C transfer at 0x%02x failed, size %d, "
116 				"err %d\n", addrdir >> 1, size, rc);
117 		else
118 			dev_err(&adap->dev,
119 				"I2C transfer at 0x%02x failed, size %d, "
120 				"err %d\n", addrdir >> 1, size, rc);
121 		goto bail;
122 	}
123 
124 	if (size == I2C_SMBUS_WORD_DATA && read) {
125 		data->word = ((u16)local[1]) << 8;
126 		data->word |= local[0];
127 	}
128 
129  bail:
130 	pmac_i2c_close(bus);
131 	return rc;
132 }
133 
134 /*
135  * Generic i2c master transfer entrypoint. This driver only support single
136  * messages (for "lame i2c" transfers). Anything else should use the smbus
137  * entry point
138  */
139 static int i2c_powermac_master_xfer(	struct i2c_adapter *adap,
140 					struct i2c_msg *msgs,
141 					int num)
142 {
143 	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
144 	int			rc = 0;
145 	int			addrdir;
146 
147 	if (msgs->flags & I2C_M_TEN)
148 		return -EINVAL;
149 	addrdir = i2c_8bit_addr_from_msg(msgs);
150 
151 	rc = pmac_i2c_open(bus, 0);
152 	if (rc) {
153 		dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
154 		return rc;
155 	}
156 	rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
157 	if (rc) {
158 		dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
159 			pmac_i2c_mode_std, rc);
160 		goto bail;
161 	}
162 	rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
163 	if (rc < 0) {
164 		if (rc == -ENXIO)
165 			dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
166 				addrdir & 1 ? "read from" : "write to",
167 				addrdir >> 1, rc);
168 		else
169 			dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
170 				addrdir & 1 ? "read from" : "write to",
171 				addrdir >> 1, rc);
172 	}
173  bail:
174 	pmac_i2c_close(bus);
175 	return rc < 0 ? rc : 1;
176 }
177 
178 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
179 {
180 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
181 		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
182 		I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
183 }
184 
185 /* For now, we only handle smbus */
186 static const struct i2c_algorithm i2c_powermac_algorithm = {
187 	.smbus_xfer	= i2c_powermac_smbus_xfer,
188 	.master_xfer	= i2c_powermac_master_xfer,
189 	.functionality	= i2c_powermac_func,
190 };
191 
192 static const struct i2c_adapter_quirks i2c_powermac_quirks = {
193 	.max_num_msgs = 1,
194 };
195 
196 static int i2c_powermac_remove(struct platform_device *dev)
197 {
198 	struct i2c_adapter	*adapter = platform_get_drvdata(dev);
199 
200 	i2c_del_adapter(adapter);
201 	memset(adapter, 0, sizeof(*adapter));
202 
203 	return 0;
204 }
205 
206 static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
207 					   struct pmac_i2c_bus *bus,
208 					   struct device_node *node)
209 {
210 	u32 prop;
211 	int ret;
212 
213 	/* First check for valid "reg" */
214 	ret = of_property_read_u32(node, "reg", &prop);
215 	if (ret == 0)
216 		return (prop & 0xff) >> 1;
217 
218 	/* Then check old-style "i2c-address" */
219 	ret = of_property_read_u32(node, "i2c-address", &prop);
220 	if (ret == 0)
221 		return (prop & 0xff) >> 1;
222 
223 	/* Now handle some devices with missing "reg" properties */
224 	if (of_node_name_eq(node, "cereal"))
225 		return 0x60;
226 	else if (of_node_name_eq(node, "deq"))
227 		return 0x34;
228 
229 	dev_warn(&adap->dev, "No i2c address for %pOF\n", node);
230 
231 	return 0xffffffff;
232 }
233 
234 static void i2c_powermac_create_one(struct i2c_adapter *adap,
235 					      const char *type,
236 					      u32 addr)
237 {
238 	struct i2c_board_info info = {};
239 	struct i2c_client *newdev;
240 
241 	strncpy(info.type, type, sizeof(info.type));
242 	info.addr = addr;
243 	newdev = i2c_new_client_device(adap, &info);
244 	if (IS_ERR(newdev))
245 		dev_err(&adap->dev,
246 			"i2c-powermac: Failure to register missing %s\n",
247 			type);
248 }
249 
250 static void i2c_powermac_add_missing(struct i2c_adapter *adap,
251 					       struct pmac_i2c_bus *bus,
252 					       bool found_onyx)
253 {
254 	struct device_node *busnode = pmac_i2c_get_bus_node(bus);
255 	int rc;
256 
257 	/* Check for the onyx audio codec */
258 #define ONYX_REG_CONTROL		67
259 	if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
260 		union i2c_smbus_data data;
261 
262 		rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
263 				    ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
264 				    &data);
265 		if (rc >= 0)
266 			i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
267 
268 		rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
269 				    ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
270 				    &data);
271 		if (rc >= 0)
272 			i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
273 	}
274 }
275 
276 static bool i2c_powermac_get_type(struct i2c_adapter *adap,
277 					    struct device_node *node,
278 					    u32 addr, char *type, int type_size)
279 {
280 	char tmp[16];
281 
282 	/*
283 	 * Note: we do _NOT_ want the standard i2c drivers to match with any of
284 	 * our powermac stuff unless they have been specifically modified to
285 	 * handle it on a case by case basis. For example, for thermal control,
286 	 * things like lm75 etc... shall match with their corresponding
287 	 * windfarm drivers, _NOT_ the generic ones, so we force a prefix of
288 	 * 'MAC', onto the modalias to make that happen
289 	 */
290 
291 	/* First try proper modalias */
292 	if (of_modalias_node(node, tmp, sizeof(tmp)) >= 0) {
293 		snprintf(type, type_size, "MAC,%s", tmp);
294 		return true;
295 	}
296 
297 	/* Now look for known workarounds */
298 	if (of_node_name_eq(node, "deq")) {
299 		/* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
300 		if (addr == 0x34) {
301 			snprintf(type, type_size, "MAC,tas3001");
302 			return true;
303 		} else if (addr == 0x35) {
304 			snprintf(type, type_size, "MAC,tas3004");
305 			return true;
306 		}
307 	}
308 
309 	dev_err(&adap->dev, "i2c-powermac: modalias failure on %pOF\n", node);
310 	return false;
311 }
312 
313 static void i2c_powermac_register_devices(struct i2c_adapter *adap,
314 						    struct pmac_i2c_bus *bus)
315 {
316 	struct i2c_client *newdev;
317 	struct device_node *node;
318 	bool found_onyx = false;
319 
320 	/*
321 	 * In some cases we end up with the via-pmu node itself, in this
322 	 * case we skip this function completely as the device-tree will
323 	 * not contain anything useful.
324 	 */
325 	if (of_node_name_eq(adap->dev.of_node, "via-pmu"))
326 		return;
327 
328 	for_each_child_of_node(adap->dev.of_node, node) {
329 		struct i2c_board_info info = {};
330 		u32 addr;
331 
332 		/* Get address & channel */
333 		addr = i2c_powermac_get_addr(adap, bus, node);
334 		if (addr == 0xffffffff)
335 			continue;
336 
337 		/* Multibus setup, check channel */
338 		if (!pmac_i2c_match_adapter(node, adap))
339 			continue;
340 
341 		dev_dbg(&adap->dev, "i2c-powermac: register %pOF\n", node);
342 
343 		/*
344 		 * Keep track of some device existence to handle
345 		 * workarounds later.
346 		 */
347 		if (of_device_is_compatible(node, "pcm3052"))
348 			found_onyx = true;
349 
350 		/* Make up a modalias */
351 		if (!i2c_powermac_get_type(adap, node, addr,
352 					   info.type, sizeof(info.type))) {
353 			continue;
354 		}
355 
356 		/* Fill out the rest of the info structure */
357 		info.addr = addr;
358 		info.irq = irq_of_parse_and_map(node, 0);
359 		info.of_node = of_node_get(node);
360 
361 		newdev = i2c_new_client_device(adap, &info);
362 		if (IS_ERR(newdev)) {
363 			dev_err(&adap->dev, "i2c-powermac: Failure to register"
364 				" %pOF\n", node);
365 			of_node_put(node);
366 			/* We do not dispose of the interrupt mapping on
367 			 * purpose. It's not necessary (interrupt cannot be
368 			 * re-used) and somebody else might have grabbed it
369 			 * via direct DT lookup so let's not bother
370 			 */
371 			continue;
372 		}
373 	}
374 
375 	/* Additional workarounds */
376 	i2c_powermac_add_missing(adap, bus, found_onyx);
377 }
378 
379 static int i2c_powermac_probe(struct platform_device *dev)
380 {
381 	struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
382 	struct device_node *parent;
383 	struct i2c_adapter *adapter;
384 	int rc;
385 
386 	if (bus == NULL)
387 		return -EINVAL;
388 	adapter = pmac_i2c_get_adapter(bus);
389 
390 	/* Ok, now we need to make up a name for the interface that will
391 	 * match what we used to do in the past, that is basically the
392 	 * controller's parent device node for keywest. PMU didn't have a
393 	 * naming convention and SMU has a different one
394 	 */
395 	switch(pmac_i2c_get_type(bus)) {
396 	case pmac_i2c_bus_keywest:
397 		parent = of_get_parent(pmac_i2c_get_controller(bus));
398 		if (parent == NULL)
399 			return -EINVAL;
400 		snprintf(adapter->name, sizeof(adapter->name), "%pOFn %d",
401 			 parent,
402 			 pmac_i2c_get_channel(bus));
403 		of_node_put(parent);
404 		break;
405 	case pmac_i2c_bus_pmu:
406 		snprintf(adapter->name, sizeof(adapter->name), "pmu %d",
407 			 pmac_i2c_get_channel(bus));
408 		break;
409 	case pmac_i2c_bus_smu:
410 		/* This is not what we used to do but I'm fixing drivers at
411 		 * the same time as this change
412 		 */
413 		snprintf(adapter->name, sizeof(adapter->name), "smu %d",
414 			 pmac_i2c_get_channel(bus));
415 		break;
416 	default:
417 		return -EINVAL;
418 	}
419 
420 	platform_set_drvdata(dev, adapter);
421 	adapter->algo = &i2c_powermac_algorithm;
422 	adapter->quirks = &i2c_powermac_quirks;
423 	i2c_set_adapdata(adapter, bus);
424 	adapter->dev.parent = &dev->dev;
425 
426 	/* Clear of_node to skip automatic registration of i2c child nodes */
427 	adapter->dev.of_node = NULL;
428 	rc = i2c_add_adapter(adapter);
429 	if (rc) {
430 		printk(KERN_ERR "i2c-powermac: Adapter %s registration "
431 		       "failed\n", adapter->name);
432 		memset(adapter, 0, sizeof(*adapter));
433 		return rc;
434 	}
435 
436 	printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
437 
438 	/* Use custom child registration due to Apple device-tree funkyness */
439 	adapter->dev.of_node = dev->dev.of_node;
440 	i2c_powermac_register_devices(adapter, bus);
441 
442 	return 0;
443 }
444 
445 static struct platform_driver i2c_powermac_driver = {
446 	.probe = i2c_powermac_probe,
447 	.remove = i2c_powermac_remove,
448 	.driver = {
449 		.name = "i2c-powermac",
450 		.bus = &platform_bus_type,
451 	},
452 };
453 
454 module_platform_driver(i2c_powermac_driver);
455 
456 MODULE_ALIAS("platform:i2c-powermac");
457