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  */
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 master transfer entrypoint. This driver only support single
131  * messages (for "lame i2c" transfers). Anything else should use the smbus
132  * entry point
133  */
134 static int i2c_powermac_master_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 
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 	.master_xfer	= i2c_powermac_master_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 
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 
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 
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 	strncpy(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 
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 
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 
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 
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