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
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        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 */
134static 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
173static 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 */
181static 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
187static const struct i2c_adapter_quirks i2c_powermac_quirks = {
188	.max_num_msgs = 1,
189};
190
191static 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
199static 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
227static 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
243static 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
269static 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
306static 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
372static 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
438static 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
447module_platform_driver(i2c_powermac_driver);
448
449MODULE_ALIAS("platform:i2c-powermac");
450