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
21MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
22MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
23MODULE_LICENSE("GPL");
24
25/*
26 * SMBUS-type transfer entrypoint
27 */
28static 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 */
139static 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
178static 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 */
186static 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
192static const struct i2c_adapter_quirks i2c_powermac_quirks = {
193	.max_num_msgs = 1,
194};
195
196static 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
206static 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
234static 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
250static 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
276static 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
313static 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
379static 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
445static 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
454module_platform_driver(i2c_powermac_driver);
455
456MODULE_ALIAS("platform:i2c-powermac");
457