xref: /linux/drivers/net/phy/mdio_bus.c (revision c4101e55974cc7d835fbd2d8e01553a3f61e9e75)
1 // SPDX-License-Identifier: GPL-2.0+
2 /* MDIO Bus interface
3  *
4  * Author: Andy Fleming
5  *
6  * Copyright (c) 2004 Freescale Semiconductor, Inc.
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/delay.h>
12 #include <linux/device.h>
13 #include <linux/errno.h>
14 #include <linux/etherdevice.h>
15 #include <linux/ethtool.h>
16 #include <linux/gpio.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/micrel_phy.h>
23 #include <linux/mii.h>
24 #include <linux/mm.h>
25 #include <linux/module.h>
26 #include <linux/netdevice.h>
27 #include <linux/of_device.h>
28 #include <linux/of_gpio.h>
29 #include <linux/of_mdio.h>
30 #include <linux/phy.h>
31 #include <linux/reset.h>
32 #include <linux/skbuff.h>
33 #include <linux/slab.h>
34 #include <linux/spinlock.h>
35 #include <linux/string.h>
36 #include <linux/uaccess.h>
37 #include <linux/unistd.h>
38 
39 #define CREATE_TRACE_POINTS
40 #include <trace/events/mdio.h>
41 
42 #include "mdio-boardinfo.h"
43 
44 static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
45 {
46 	/* Deassert the optional reset signal */
47 	mdiodev->reset_gpio = gpiod_get_optional(&mdiodev->dev,
48 						 "reset", GPIOD_OUT_LOW);
49 	if (IS_ERR(mdiodev->reset_gpio))
50 		return PTR_ERR(mdiodev->reset_gpio);
51 
52 	if (mdiodev->reset_gpio)
53 		gpiod_set_consumer_name(mdiodev->reset_gpio, "PHY reset");
54 
55 	return 0;
56 }
57 
58 static int mdiobus_register_reset(struct mdio_device *mdiodev)
59 {
60 	struct reset_control *reset;
61 
62 	reset = reset_control_get_optional_exclusive(&mdiodev->dev, "phy");
63 	if (IS_ERR(reset))
64 		return PTR_ERR(reset);
65 
66 	mdiodev->reset_ctrl = reset;
67 
68 	return 0;
69 }
70 
71 int mdiobus_register_device(struct mdio_device *mdiodev)
72 {
73 	int err;
74 
75 	if (mdiodev->bus->mdio_map[mdiodev->addr])
76 		return -EBUSY;
77 
78 	if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY) {
79 		err = mdiobus_register_gpiod(mdiodev);
80 		if (err)
81 			return err;
82 
83 		err = mdiobus_register_reset(mdiodev);
84 		if (err)
85 			return err;
86 
87 		/* Assert the reset signal */
88 		mdio_device_reset(mdiodev, 1);
89 	}
90 
91 	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
92 
93 	return 0;
94 }
95 EXPORT_SYMBOL(mdiobus_register_device);
96 
97 int mdiobus_unregister_device(struct mdio_device *mdiodev)
98 {
99 	if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
100 		return -EINVAL;
101 
102 	reset_control_put(mdiodev->reset_ctrl);
103 
104 	mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
105 
106 	return 0;
107 }
108 EXPORT_SYMBOL(mdiobus_unregister_device);
109 
110 static struct mdio_device *mdiobus_find_device(struct mii_bus *bus, int addr)
111 {
112 	bool addr_valid = addr >= 0 && addr < ARRAY_SIZE(bus->mdio_map);
113 
114 	if (WARN_ONCE(!addr_valid, "addr %d out of range\n", addr))
115 		return NULL;
116 
117 	return bus->mdio_map[addr];
118 }
119 
120 struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
121 {
122 	struct mdio_device *mdiodev;
123 
124 	mdiodev = mdiobus_find_device(bus, addr);
125 	if (!mdiodev)
126 		return NULL;
127 
128 	if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
129 		return NULL;
130 
131 	return container_of(mdiodev, struct phy_device, mdio);
132 }
133 EXPORT_SYMBOL(mdiobus_get_phy);
134 
135 bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
136 {
137 	return mdiobus_find_device(bus, addr) != NULL;
138 }
139 EXPORT_SYMBOL(mdiobus_is_registered_device);
140 
141 /**
142  * mdiobus_alloc_size - allocate a mii_bus structure
143  * @size: extra amount of memory to allocate for private storage.
144  * If non-zero, then bus->priv is points to that memory.
145  *
146  * Description: called by a bus driver to allocate an mii_bus
147  * structure to fill in.
148  */
149 struct mii_bus *mdiobus_alloc_size(size_t size)
150 {
151 	struct mii_bus *bus;
152 	size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
153 	size_t alloc_size;
154 	int i;
155 
156 	/* If we alloc extra space, it should be aligned */
157 	if (size)
158 		alloc_size = aligned_size + size;
159 	else
160 		alloc_size = sizeof(*bus);
161 
162 	bus = kzalloc(alloc_size, GFP_KERNEL);
163 	if (!bus)
164 		return NULL;
165 
166 	bus->state = MDIOBUS_ALLOCATED;
167 	if (size)
168 		bus->priv = (void *)bus + aligned_size;
169 
170 	/* Initialise the interrupts to polling and 64-bit seqcounts */
171 	for (i = 0; i < PHY_MAX_ADDR; i++) {
172 		bus->irq[i] = PHY_POLL;
173 		u64_stats_init(&bus->stats[i].syncp);
174 	}
175 
176 	return bus;
177 }
178 EXPORT_SYMBOL(mdiobus_alloc_size);
179 
180 /**
181  * mdiobus_release - mii_bus device release callback
182  * @d: the target struct device that contains the mii_bus
183  *
184  * Description: called when the last reference to an mii_bus is
185  * dropped, to free the underlying memory.
186  */
187 static void mdiobus_release(struct device *d)
188 {
189 	struct mii_bus *bus = to_mii_bus(d);
190 
191 	WARN(bus->state != MDIOBUS_RELEASED &&
192 	     /* for compatibility with error handling in drivers */
193 	     bus->state != MDIOBUS_ALLOCATED,
194 	     "%s: not in RELEASED or ALLOCATED state\n",
195 	     bus->id);
196 
197 	if (bus->state == MDIOBUS_RELEASED)
198 		fwnode_handle_put(dev_fwnode(d));
199 
200 	kfree(bus);
201 }
202 
203 struct mdio_bus_stat_attr {
204 	int addr;
205 	unsigned int field_offset;
206 };
207 
208 static u64 mdio_bus_get_stat(struct mdio_bus_stats *s, unsigned int offset)
209 {
210 	const char *p = (const char *)s + offset;
211 	unsigned int start;
212 	u64 val = 0;
213 
214 	do {
215 		start = u64_stats_fetch_begin(&s->syncp);
216 		val = u64_stats_read((const u64_stats_t *)p);
217 	} while (u64_stats_fetch_retry(&s->syncp, start));
218 
219 	return val;
220 }
221 
222 static u64 mdio_bus_get_global_stat(struct mii_bus *bus, unsigned int offset)
223 {
224 	unsigned int i;
225 	u64 val = 0;
226 
227 	for (i = 0; i < PHY_MAX_ADDR; i++)
228 		val += mdio_bus_get_stat(&bus->stats[i], offset);
229 
230 	return val;
231 }
232 
233 static ssize_t mdio_bus_stat_field_show(struct device *dev,
234 					struct device_attribute *attr,
235 					char *buf)
236 {
237 	struct mii_bus *bus = to_mii_bus(dev);
238 	struct mdio_bus_stat_attr *sattr;
239 	struct dev_ext_attribute *eattr;
240 	u64 val;
241 
242 	eattr = container_of(attr, struct dev_ext_attribute, attr);
243 	sattr = eattr->var;
244 
245 	if (sattr->addr < 0)
246 		val = mdio_bus_get_global_stat(bus, sattr->field_offset);
247 	else
248 		val = mdio_bus_get_stat(&bus->stats[sattr->addr],
249 					sattr->field_offset);
250 
251 	return sysfs_emit(buf, "%llu\n", val);
252 }
253 
254 static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
255 					       struct device_attribute *attr,
256 					       char *buf)
257 {
258 	struct mdio_device *mdiodev = to_mdio_device(dev);
259 	struct mii_bus *bus = mdiodev->bus;
260 	struct mdio_bus_stat_attr *sattr;
261 	struct dev_ext_attribute *eattr;
262 	int addr = mdiodev->addr;
263 	u64 val;
264 
265 	eattr = container_of(attr, struct dev_ext_attribute, attr);
266 	sattr = eattr->var;
267 
268 	val = mdio_bus_get_stat(&bus->stats[addr], sattr->field_offset);
269 
270 	return sysfs_emit(buf, "%llu\n", val);
271 }
272 
273 #define MDIO_BUS_STATS_ATTR_DECL(field, file)				\
274 static struct dev_ext_attribute dev_attr_mdio_bus_##field = {		\
275 	.attr = { .attr = { .name = file, .mode = 0444 },		\
276 		     .show = mdio_bus_stat_field_show,			\
277 	},								\
278 	.var = &((struct mdio_bus_stat_attr) {				\
279 		-1, offsetof(struct mdio_bus_stats, field)		\
280 	}),								\
281 };									\
282 static struct dev_ext_attribute dev_attr_mdio_bus_device_##field = {	\
283 	.attr = { .attr = { .name = file, .mode = 0444 },		\
284 		     .show = mdio_bus_device_stat_field_show,		\
285 	},								\
286 	.var = &((struct mdio_bus_stat_attr) {				\
287 		-1, offsetof(struct mdio_bus_stats, field)		\
288 	}),								\
289 };
290 
291 #define MDIO_BUS_STATS_ATTR(field)					\
292 	MDIO_BUS_STATS_ATTR_DECL(field, __stringify(field))
293 
294 MDIO_BUS_STATS_ATTR(transfers);
295 MDIO_BUS_STATS_ATTR(errors);
296 MDIO_BUS_STATS_ATTR(writes);
297 MDIO_BUS_STATS_ATTR(reads);
298 
299 #define MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr, file)		\
300 static struct dev_ext_attribute dev_attr_mdio_bus_addr_##field##_##addr = { \
301 	.attr = { .attr = { .name = file, .mode = 0444 },		\
302 		     .show = mdio_bus_stat_field_show,			\
303 	},								\
304 	.var = &((struct mdio_bus_stat_attr) {				\
305 		addr, offsetof(struct mdio_bus_stats, field)		\
306 	}),								\
307 }
308 
309 #define MDIO_BUS_STATS_ADDR_ATTR(field, addr)				\
310 	MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr,			\
311 				 __stringify(field) "_" __stringify(addr))
312 
313 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(addr)			\
314 	MDIO_BUS_STATS_ADDR_ATTR(transfers, addr);			\
315 	MDIO_BUS_STATS_ADDR_ATTR(errors, addr);				\
316 	MDIO_BUS_STATS_ADDR_ATTR(writes, addr);				\
317 	MDIO_BUS_STATS_ADDR_ATTR(reads, addr)				\
318 
319 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(0);
320 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(1);
321 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(2);
322 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(3);
323 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(4);
324 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(5);
325 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(6);
326 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(7);
327 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(8);
328 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(9);
329 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(10);
330 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(11);
331 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(12);
332 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(13);
333 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(14);
334 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(15);
335 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(16);
336 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(17);
337 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(18);
338 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(19);
339 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(20);
340 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(21);
341 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(22);
342 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(23);
343 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(24);
344 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(25);
345 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(26);
346 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(27);
347 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(28);
348 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(29);
349 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(30);
350 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(31);
351 
352 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP(addr)				\
353 	&dev_attr_mdio_bus_addr_transfers_##addr.attr.attr,		\
354 	&dev_attr_mdio_bus_addr_errors_##addr.attr.attr,		\
355 	&dev_attr_mdio_bus_addr_writes_##addr.attr.attr,		\
356 	&dev_attr_mdio_bus_addr_reads_##addr.attr.attr			\
357 
358 static struct attribute *mdio_bus_statistics_attrs[] = {
359 	&dev_attr_mdio_bus_transfers.attr.attr,
360 	&dev_attr_mdio_bus_errors.attr.attr,
361 	&dev_attr_mdio_bus_writes.attr.attr,
362 	&dev_attr_mdio_bus_reads.attr.attr,
363 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(0),
364 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(1),
365 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(2),
366 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(3),
367 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(4),
368 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(5),
369 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(6),
370 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(7),
371 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(8),
372 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(9),
373 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(10),
374 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(11),
375 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(12),
376 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(13),
377 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(14),
378 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(15),
379 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(16),
380 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(17),
381 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(18),
382 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(19),
383 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(20),
384 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(21),
385 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(22),
386 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(23),
387 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(24),
388 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(25),
389 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(26),
390 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(27),
391 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(28),
392 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(29),
393 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(30),
394 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(31),
395 	NULL,
396 };
397 
398 static const struct attribute_group mdio_bus_statistics_group = {
399 	.name	= "statistics",
400 	.attrs	= mdio_bus_statistics_attrs,
401 };
402 
403 static const struct attribute_group *mdio_bus_groups[] = {
404 	&mdio_bus_statistics_group,
405 	NULL,
406 };
407 
408 static struct class mdio_bus_class = {
409 	.name		= "mdio_bus",
410 	.dev_release	= mdiobus_release,
411 	.dev_groups	= mdio_bus_groups,
412 };
413 
414 /**
415  * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
416  * @mdio_name: The name of a mdiobus.
417  *
418  * Returns a reference to the mii_bus, or NULL if none found.  The
419  * embedded struct device will have its reference count incremented,
420  * and this must be put_deviced'ed once the bus is finished with.
421  */
422 struct mii_bus *mdio_find_bus(const char *mdio_name)
423 {
424 	struct device *d;
425 
426 	d = class_find_device_by_name(&mdio_bus_class, mdio_name);
427 	return d ? to_mii_bus(d) : NULL;
428 }
429 EXPORT_SYMBOL(mdio_find_bus);
430 
431 #if IS_ENABLED(CONFIG_OF_MDIO)
432 /**
433  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
434  * @mdio_bus_np: Pointer to the mii_bus.
435  *
436  * Returns a reference to the mii_bus, or NULL if none found.  The
437  * embedded struct device will have its reference count incremented,
438  * and this must be put once the bus is finished with.
439  *
440  * Because the association of a device_node and mii_bus is made via
441  * of_mdiobus_register(), the mii_bus cannot be found before it is
442  * registered with of_mdiobus_register().
443  *
444  */
445 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
446 {
447 	struct device *d;
448 
449 	if (!mdio_bus_np)
450 		return NULL;
451 
452 	d = class_find_device_by_of_node(&mdio_bus_class, mdio_bus_np);
453 	return d ? to_mii_bus(d) : NULL;
454 }
455 EXPORT_SYMBOL(of_mdio_find_bus);
456 
457 /* Walk the list of subnodes of a mdio bus and look for a node that
458  * matches the mdio device's address with its 'reg' property. If
459  * found, set the of_node pointer for the mdio device. This allows
460  * auto-probed phy devices to be supplied with information passed in
461  * via DT.
462  */
463 static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
464 				    struct mdio_device *mdiodev)
465 {
466 	struct device *dev = &mdiodev->dev;
467 	struct device_node *child;
468 
469 	if (dev->of_node || !bus->dev.of_node)
470 		return;
471 
472 	for_each_available_child_of_node(bus->dev.of_node, child) {
473 		int addr;
474 
475 		addr = of_mdio_parse_addr(dev, child);
476 		if (addr < 0)
477 			continue;
478 
479 		if (addr == mdiodev->addr) {
480 			device_set_node(dev, of_fwnode_handle(child));
481 			/* The refcount on "child" is passed to the mdio
482 			 * device. Do _not_ use of_node_put(child) here.
483 			 */
484 			return;
485 		}
486 	}
487 }
488 #else /* !IS_ENABLED(CONFIG_OF_MDIO) */
489 static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
490 					   struct mdio_device *mdiodev)
491 {
492 }
493 #endif
494 
495 /**
496  * mdiobus_create_device - create a full MDIO device given
497  * a mdio_board_info structure
498  * @bus: MDIO bus to create the devices on
499  * @bi: mdio_board_info structure describing the devices
500  *
501  * Returns 0 on success or < 0 on error.
502  */
503 static int mdiobus_create_device(struct mii_bus *bus,
504 				 struct mdio_board_info *bi)
505 {
506 	struct mdio_device *mdiodev;
507 	int ret = 0;
508 
509 	mdiodev = mdio_device_create(bus, bi->mdio_addr);
510 	if (IS_ERR(mdiodev))
511 		return -ENODEV;
512 
513 	strscpy(mdiodev->modalias, bi->modalias,
514 		sizeof(mdiodev->modalias));
515 	mdiodev->bus_match = mdio_device_bus_match;
516 	mdiodev->dev.platform_data = (void *)bi->platform_data;
517 
518 	ret = mdio_device_register(mdiodev);
519 	if (ret)
520 		mdio_device_free(mdiodev);
521 
522 	return ret;
523 }
524 
525 static struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr, bool c45)
526 {
527 	struct phy_device *phydev = ERR_PTR(-ENODEV);
528 	int err;
529 
530 	phydev = get_phy_device(bus, addr, c45);
531 	if (IS_ERR(phydev))
532 		return phydev;
533 
534 	/* For DT, see if the auto-probed phy has a corresponding child
535 	 * in the bus node, and set the of_node pointer in this case.
536 	 */
537 	of_mdiobus_link_mdiodev(bus, &phydev->mdio);
538 
539 	err = phy_device_register(phydev);
540 	if (err) {
541 		phy_device_free(phydev);
542 		return ERR_PTR(-ENODEV);
543 	}
544 
545 	return phydev;
546 }
547 
548 /**
549  * mdiobus_scan_c22 - scan one address on a bus for C22 MDIO devices.
550  * @bus: mii_bus to scan
551  * @addr: address on bus to scan
552  *
553  * This function scans one address on the MDIO bus, looking for
554  * devices which can be identified using a vendor/product ID in
555  * registers 2 and 3. Not all MDIO devices have such registers, but
556  * PHY devices typically do. Hence this function assumes anything
557  * found is a PHY, or can be treated as a PHY. Other MDIO devices,
558  * such as switches, will probably not be found during the scan.
559  */
560 struct phy_device *mdiobus_scan_c22(struct mii_bus *bus, int addr)
561 {
562 	return mdiobus_scan(bus, addr, false);
563 }
564 EXPORT_SYMBOL(mdiobus_scan_c22);
565 
566 /**
567  * mdiobus_scan_c45 - scan one address on a bus for C45 MDIO devices.
568  * @bus: mii_bus to scan
569  * @addr: address on bus to scan
570  *
571  * This function scans one address on the MDIO bus, looking for
572  * devices which can be identified using a vendor/product ID in
573  * registers 2 and 3. Not all MDIO devices have such registers, but
574  * PHY devices typically do. Hence this function assumes anything
575  * found is a PHY, or can be treated as a PHY. Other MDIO devices,
576  * such as switches, will probably not be found during the scan.
577  */
578 static struct phy_device *mdiobus_scan_c45(struct mii_bus *bus, int addr)
579 {
580 	return mdiobus_scan(bus, addr, true);
581 }
582 
583 static int mdiobus_scan_bus_c22(struct mii_bus *bus)
584 {
585 	int i;
586 
587 	for (i = 0; i < PHY_MAX_ADDR; i++) {
588 		if ((bus->phy_mask & BIT(i)) == 0) {
589 			struct phy_device *phydev;
590 
591 			phydev = mdiobus_scan_c22(bus, i);
592 			if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV))
593 				return PTR_ERR(phydev);
594 		}
595 	}
596 	return 0;
597 }
598 
599 static int mdiobus_scan_bus_c45(struct mii_bus *bus)
600 {
601 	int i;
602 
603 	for (i = 0; i < PHY_MAX_ADDR; i++) {
604 		if ((bus->phy_mask & BIT(i)) == 0) {
605 			struct phy_device *phydev;
606 
607 			/* Don't scan C45 if we already have a C22 device */
608 			if (bus->mdio_map[i])
609 				continue;
610 
611 			phydev = mdiobus_scan_c45(bus, i);
612 			if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV))
613 				return PTR_ERR(phydev);
614 		}
615 	}
616 	return 0;
617 }
618 
619 /* There are some C22 PHYs which do bad things when where is a C45
620  * transaction on the bus, like accepting a read themselves, and
621  * stomping over the true devices reply, to performing a write to
622  * themselves which was intended for another device. Now that C22
623  * devices have been found, see if any of them are bad for C45, and if we
624  * should skip the C45 scan.
625  */
626 static bool mdiobus_prevent_c45_scan(struct mii_bus *bus)
627 {
628 	int i;
629 
630 	for (i = 0; i < PHY_MAX_ADDR; i++) {
631 		struct phy_device *phydev;
632 		u32 oui;
633 
634 		phydev = mdiobus_get_phy(bus, i);
635 		if (!phydev)
636 			continue;
637 		oui = phydev->phy_id >> 10;
638 
639 		if (oui == MICREL_OUI)
640 			return true;
641 	}
642 	return false;
643 }
644 
645 /**
646  * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
647  * @bus: target mii_bus
648  * @owner: module containing bus accessor functions
649  *
650  * Description: Called by a bus driver to bring up all the PHYs
651  *   on a given bus, and attach them to the bus. Drivers should use
652  *   mdiobus_register() rather than __mdiobus_register() unless they
653  *   need to pass a specific owner module. MDIO devices which are not
654  *   PHYs will not be brought up by this function. They are expected
655  *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
656  *
657  * Returns 0 on success or < 0 on error.
658  */
659 int __mdiobus_register(struct mii_bus *bus, struct module *owner)
660 {
661 	struct mdio_device *mdiodev;
662 	struct gpio_desc *gpiod;
663 	bool prevent_c45_scan;
664 	int i, err;
665 
666 	if (!bus || !bus->name)
667 		return -EINVAL;
668 
669 	/* An access method always needs both read and write operations */
670 	if (!!bus->read != !!bus->write || !!bus->read_c45 != !!bus->write_c45)
671 		return -EINVAL;
672 
673 	/* At least one method is mandatory */
674 	if (!bus->read && !bus->read_c45)
675 		return -EINVAL;
676 
677 	if (bus->parent && bus->parent->of_node)
678 		bus->parent->of_node->fwnode.flags |=
679 					FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;
680 
681 	WARN(bus->state != MDIOBUS_ALLOCATED &&
682 	     bus->state != MDIOBUS_UNREGISTERED,
683 	     "%s: not in ALLOCATED or UNREGISTERED state\n", bus->id);
684 
685 	bus->owner = owner;
686 	bus->dev.parent = bus->parent;
687 	bus->dev.class = &mdio_bus_class;
688 	bus->dev.groups = NULL;
689 	dev_set_name(&bus->dev, "%s", bus->id);
690 
691 	/* If the bus state is allocated, we're registering a fresh bus
692 	 * that may have a fwnode associated with it. Grab a reference
693 	 * to the fwnode. This will be dropped when the bus is released.
694 	 * If the bus was set to unregistered, it means that the bus was
695 	 * previously registered, and we've already grabbed a reference.
696 	 */
697 	if (bus->state == MDIOBUS_ALLOCATED)
698 		fwnode_handle_get(dev_fwnode(&bus->dev));
699 
700 	/* We need to set state to MDIOBUS_UNREGISTERED to correctly release
701 	 * the device in mdiobus_free()
702 	 *
703 	 * State will be updated later in this function in case of success
704 	 */
705 	bus->state = MDIOBUS_UNREGISTERED;
706 
707 	err = device_register(&bus->dev);
708 	if (err) {
709 		pr_err("mii_bus %s failed to register\n", bus->id);
710 		return -EINVAL;
711 	}
712 
713 	mutex_init(&bus->mdio_lock);
714 	mutex_init(&bus->shared_lock);
715 
716 	/* assert bus level PHY GPIO reset */
717 	gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH);
718 	if (IS_ERR(gpiod)) {
719 		err = dev_err_probe(&bus->dev, PTR_ERR(gpiod),
720 				    "mii_bus %s couldn't get reset GPIO\n",
721 				    bus->id);
722 		device_del(&bus->dev);
723 		return err;
724 	} else	if (gpiod) {
725 		bus->reset_gpiod = gpiod;
726 		fsleep(bus->reset_delay_us);
727 		gpiod_set_value_cansleep(gpiod, 0);
728 		if (bus->reset_post_delay_us > 0)
729 			fsleep(bus->reset_post_delay_us);
730 	}
731 
732 	if (bus->reset) {
733 		err = bus->reset(bus);
734 		if (err)
735 			goto error_reset_gpiod;
736 	}
737 
738 	if (bus->read) {
739 		err = mdiobus_scan_bus_c22(bus);
740 		if (err)
741 			goto error;
742 	}
743 
744 	prevent_c45_scan = mdiobus_prevent_c45_scan(bus);
745 
746 	if (!prevent_c45_scan && bus->read_c45) {
747 		err = mdiobus_scan_bus_c45(bus);
748 		if (err)
749 			goto error;
750 	}
751 
752 	mdiobus_setup_mdiodev_from_board_info(bus, mdiobus_create_device);
753 
754 	bus->state = MDIOBUS_REGISTERED;
755 	dev_dbg(&bus->dev, "probed\n");
756 	return 0;
757 
758 error:
759 	for (i = 0; i < PHY_MAX_ADDR; i++) {
760 		mdiodev = bus->mdio_map[i];
761 		if (!mdiodev)
762 			continue;
763 
764 		mdiodev->device_remove(mdiodev);
765 		mdiodev->device_free(mdiodev);
766 	}
767 error_reset_gpiod:
768 	/* Put PHYs in RESET to save power */
769 	if (bus->reset_gpiod)
770 		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
771 
772 	device_del(&bus->dev);
773 	return err;
774 }
775 EXPORT_SYMBOL(__mdiobus_register);
776 
777 void mdiobus_unregister(struct mii_bus *bus)
778 {
779 	struct mdio_device *mdiodev;
780 	int i;
781 
782 	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
783 		return;
784 	bus->state = MDIOBUS_UNREGISTERED;
785 
786 	for (i = 0; i < PHY_MAX_ADDR; i++) {
787 		mdiodev = bus->mdio_map[i];
788 		if (!mdiodev)
789 			continue;
790 
791 		if (mdiodev->reset_gpio)
792 			gpiod_put(mdiodev->reset_gpio);
793 
794 		mdiodev->device_remove(mdiodev);
795 		mdiodev->device_free(mdiodev);
796 	}
797 
798 	/* Put PHYs in RESET to save power */
799 	if (bus->reset_gpiod)
800 		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
801 
802 	device_del(&bus->dev);
803 }
804 EXPORT_SYMBOL(mdiobus_unregister);
805 
806 /**
807  * mdiobus_free - free a struct mii_bus
808  * @bus: mii_bus to free
809  *
810  * This function releases the reference to the underlying device
811  * object in the mii_bus.  If this is the last reference, the mii_bus
812  * will be freed.
813  */
814 void mdiobus_free(struct mii_bus *bus)
815 {
816 	/* For compatibility with error handling in drivers. */
817 	if (bus->state == MDIOBUS_ALLOCATED) {
818 		kfree(bus);
819 		return;
820 	}
821 
822 	WARN(bus->state != MDIOBUS_UNREGISTERED,
823 	     "%s: not in UNREGISTERED state\n", bus->id);
824 	bus->state = MDIOBUS_RELEASED;
825 
826 	put_device(&bus->dev);
827 }
828 EXPORT_SYMBOL(mdiobus_free);
829 
830 static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
831 {
832 	preempt_disable();
833 	u64_stats_update_begin(&stats->syncp);
834 
835 	u64_stats_inc(&stats->transfers);
836 	if (ret < 0) {
837 		u64_stats_inc(&stats->errors);
838 		goto out;
839 	}
840 
841 	if (op)
842 		u64_stats_inc(&stats->reads);
843 	else
844 		u64_stats_inc(&stats->writes);
845 out:
846 	u64_stats_update_end(&stats->syncp);
847 	preempt_enable();
848 }
849 
850 /**
851  * __mdiobus_read - Unlocked version of the mdiobus_read function
852  * @bus: the mii_bus struct
853  * @addr: the phy address
854  * @regnum: register number to read
855  *
856  * Read a MDIO bus register. Caller must hold the mdio bus lock.
857  *
858  * NOTE: MUST NOT be called from interrupt context.
859  */
860 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
861 {
862 	int retval;
863 
864 	lockdep_assert_held_once(&bus->mdio_lock);
865 
866 	if (bus->read)
867 		retval = bus->read(bus, addr, regnum);
868 	else
869 		retval = -EOPNOTSUPP;
870 
871 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
872 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
873 
874 	return retval;
875 }
876 EXPORT_SYMBOL(__mdiobus_read);
877 
878 /**
879  * __mdiobus_write - Unlocked version of the mdiobus_write function
880  * @bus: the mii_bus struct
881  * @addr: the phy address
882  * @regnum: register number to write
883  * @val: value to write to @regnum
884  *
885  * Write a MDIO bus register. Caller must hold the mdio bus lock.
886  *
887  * NOTE: MUST NOT be called from interrupt context.
888  */
889 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
890 {
891 	int err;
892 
893 	lockdep_assert_held_once(&bus->mdio_lock);
894 
895 	if (bus->write)
896 		err = bus->write(bus, addr, regnum, val);
897 	else
898 		err = -EOPNOTSUPP;
899 
900 	trace_mdio_access(bus, 0, addr, regnum, val, err);
901 	mdiobus_stats_acct(&bus->stats[addr], false, err);
902 
903 	return err;
904 }
905 EXPORT_SYMBOL(__mdiobus_write);
906 
907 /**
908  * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
909  * @bus: the mii_bus struct
910  * @addr: the phy address
911  * @regnum: register number to modify
912  * @mask: bit mask of bits to clear
913  * @set: bit mask of bits to set
914  *
915  * Read, modify, and if any change, write the register value back to the
916  * device. Any error returns a negative number.
917  *
918  * NOTE: MUST NOT be called from interrupt context.
919  */
920 int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
921 			     u16 mask, u16 set)
922 {
923 	int new, ret;
924 
925 	ret = __mdiobus_read(bus, addr, regnum);
926 	if (ret < 0)
927 		return ret;
928 
929 	new = (ret & ~mask) | set;
930 	if (new == ret)
931 		return 0;
932 
933 	ret = __mdiobus_write(bus, addr, regnum, new);
934 
935 	return ret < 0 ? ret : 1;
936 }
937 EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
938 
939 /**
940  * __mdiobus_c45_read - Unlocked version of the mdiobus_c45_read function
941  * @bus: the mii_bus struct
942  * @addr: the phy address
943  * @devad: device address to read
944  * @regnum: register number to read
945  *
946  * Read a MDIO bus register. Caller must hold the mdio bus lock.
947  *
948  * NOTE: MUST NOT be called from interrupt context.
949  */
950 int __mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
951 {
952 	int retval;
953 
954 	lockdep_assert_held_once(&bus->mdio_lock);
955 
956 	if (bus->read_c45)
957 		retval = bus->read_c45(bus, addr, devad, regnum);
958 	else
959 		retval = -EOPNOTSUPP;
960 
961 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
962 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
963 
964 	return retval;
965 }
966 EXPORT_SYMBOL(__mdiobus_c45_read);
967 
968 /**
969  * __mdiobus_c45_write - Unlocked version of the mdiobus_write function
970  * @bus: the mii_bus struct
971  * @addr: the phy address
972  * @devad: device address to read
973  * @regnum: register number to write
974  * @val: value to write to @regnum
975  *
976  * Write a MDIO bus register. Caller must hold the mdio bus lock.
977  *
978  * NOTE: MUST NOT be called from interrupt context.
979  */
980 int __mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
981 			u16 val)
982 {
983 	int err;
984 
985 	lockdep_assert_held_once(&bus->mdio_lock);
986 
987 	if (bus->write_c45)
988 		err = bus->write_c45(bus, addr, devad, regnum, val);
989 	else
990 		err = -EOPNOTSUPP;
991 
992 	trace_mdio_access(bus, 0, addr, regnum, val, err);
993 	mdiobus_stats_acct(&bus->stats[addr], false, err);
994 
995 	return err;
996 }
997 EXPORT_SYMBOL(__mdiobus_c45_write);
998 
999 /**
1000  * __mdiobus_c45_modify_changed - Unlocked version of the mdiobus_modify function
1001  * @bus: the mii_bus struct
1002  * @addr: the phy address
1003  * @devad: device address to read
1004  * @regnum: register number to modify
1005  * @mask: bit mask of bits to clear
1006  * @set: bit mask of bits to set
1007  *
1008  * Read, modify, and if any change, write the register value back to the
1009  * device. Any error returns a negative number.
1010  *
1011  * NOTE: MUST NOT be called from interrupt context.
1012  */
1013 static int __mdiobus_c45_modify_changed(struct mii_bus *bus, int addr,
1014 					int devad, u32 regnum, u16 mask,
1015 					u16 set)
1016 {
1017 	int new, ret;
1018 
1019 	ret = __mdiobus_c45_read(bus, addr, devad, regnum);
1020 	if (ret < 0)
1021 		return ret;
1022 
1023 	new = (ret & ~mask) | set;
1024 	if (new == ret)
1025 		return 0;
1026 
1027 	ret = __mdiobus_c45_write(bus, addr, devad, regnum, new);
1028 
1029 	return ret < 0 ? ret : 1;
1030 }
1031 
1032 /**
1033  * mdiobus_read_nested - Nested version of the mdiobus_read function
1034  * @bus: the mii_bus struct
1035  * @addr: the phy address
1036  * @regnum: register number to read
1037  *
1038  * In case of nested MDIO bus access avoid lockdep false positives by
1039  * using mutex_lock_nested().
1040  *
1041  * NOTE: MUST NOT be called from interrupt context,
1042  * because the bus read/write functions may wait for an interrupt
1043  * to conclude the operation.
1044  */
1045 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
1046 {
1047 	int retval;
1048 
1049 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
1050 	retval = __mdiobus_read(bus, addr, regnum);
1051 	mutex_unlock(&bus->mdio_lock);
1052 
1053 	return retval;
1054 }
1055 EXPORT_SYMBOL(mdiobus_read_nested);
1056 
1057 /**
1058  * mdiobus_read - Convenience function for reading a given MII mgmt register
1059  * @bus: the mii_bus struct
1060  * @addr: the phy address
1061  * @regnum: register number to read
1062  *
1063  * NOTE: MUST NOT be called from interrupt context,
1064  * because the bus read/write functions may wait for an interrupt
1065  * to conclude the operation.
1066  */
1067 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
1068 {
1069 	int retval;
1070 
1071 	mutex_lock(&bus->mdio_lock);
1072 	retval = __mdiobus_read(bus, addr, regnum);
1073 	mutex_unlock(&bus->mdio_lock);
1074 
1075 	return retval;
1076 }
1077 EXPORT_SYMBOL(mdiobus_read);
1078 
1079 /**
1080  * mdiobus_c45_read - Convenience function for reading a given MII mgmt register
1081  * @bus: the mii_bus struct
1082  * @addr: the phy address
1083  * @devad: device address to read
1084  * @regnum: register number to read
1085  *
1086  * NOTE: MUST NOT be called from interrupt context,
1087  * because the bus read/write functions may wait for an interrupt
1088  * to conclude the operation.
1089  */
1090 int mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
1091 {
1092 	int retval;
1093 
1094 	mutex_lock(&bus->mdio_lock);
1095 	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
1096 	mutex_unlock(&bus->mdio_lock);
1097 
1098 	return retval;
1099 }
1100 EXPORT_SYMBOL(mdiobus_c45_read);
1101 
1102 /**
1103  * mdiobus_c45_read_nested - Nested version of the mdiobus_c45_read function
1104  * @bus: the mii_bus struct
1105  * @addr: the phy address
1106  * @devad: device address to read
1107  * @regnum: register number to read
1108  *
1109  * In case of nested MDIO bus access avoid lockdep false positives by
1110  * using mutex_lock_nested().
1111  *
1112  * NOTE: MUST NOT be called from interrupt context,
1113  * because the bus read/write functions may wait for an interrupt
1114  * to conclude the operation.
1115  */
1116 int mdiobus_c45_read_nested(struct mii_bus *bus, int addr, int devad,
1117 			    u32 regnum)
1118 {
1119 	int retval;
1120 
1121 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
1122 	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
1123 	mutex_unlock(&bus->mdio_lock);
1124 
1125 	return retval;
1126 }
1127 EXPORT_SYMBOL(mdiobus_c45_read_nested);
1128 
1129 /**
1130  * mdiobus_write_nested - Nested version of the mdiobus_write function
1131  * @bus: the mii_bus struct
1132  * @addr: the phy address
1133  * @regnum: register number to write
1134  * @val: value to write to @regnum
1135  *
1136  * In case of nested MDIO bus access avoid lockdep false positives by
1137  * using mutex_lock_nested().
1138  *
1139  * NOTE: MUST NOT be called from interrupt context,
1140  * because the bus read/write functions may wait for an interrupt
1141  * to conclude the operation.
1142  */
1143 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
1144 {
1145 	int err;
1146 
1147 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
1148 	err = __mdiobus_write(bus, addr, regnum, val);
1149 	mutex_unlock(&bus->mdio_lock);
1150 
1151 	return err;
1152 }
1153 EXPORT_SYMBOL(mdiobus_write_nested);
1154 
1155 /**
1156  * mdiobus_write - Convenience function for writing a given MII mgmt register
1157  * @bus: the mii_bus struct
1158  * @addr: the phy address
1159  * @regnum: register number to write
1160  * @val: value to write to @regnum
1161  *
1162  * NOTE: MUST NOT be called from interrupt context,
1163  * because the bus read/write functions may wait for an interrupt
1164  * to conclude the operation.
1165  */
1166 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
1167 {
1168 	int err;
1169 
1170 	mutex_lock(&bus->mdio_lock);
1171 	err = __mdiobus_write(bus, addr, regnum, val);
1172 	mutex_unlock(&bus->mdio_lock);
1173 
1174 	return err;
1175 }
1176 EXPORT_SYMBOL(mdiobus_write);
1177 
1178 /**
1179  * mdiobus_c45_write - Convenience function for writing a given MII mgmt register
1180  * @bus: the mii_bus struct
1181  * @addr: the phy address
1182  * @devad: device address to read
1183  * @regnum: register number to write
1184  * @val: value to write to @regnum
1185  *
1186  * NOTE: MUST NOT be called from interrupt context,
1187  * because the bus read/write functions may wait for an interrupt
1188  * to conclude the operation.
1189  */
1190 int mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
1191 		      u16 val)
1192 {
1193 	int err;
1194 
1195 	mutex_lock(&bus->mdio_lock);
1196 	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
1197 	mutex_unlock(&bus->mdio_lock);
1198 
1199 	return err;
1200 }
1201 EXPORT_SYMBOL(mdiobus_c45_write);
1202 
1203 /**
1204  * mdiobus_c45_write_nested - Nested version of the mdiobus_c45_write function
1205  * @bus: the mii_bus struct
1206  * @addr: the phy address
1207  * @devad: device address to read
1208  * @regnum: register number to write
1209  * @val: value to write to @regnum
1210  *
1211  * In case of nested MDIO bus access avoid lockdep false positives by
1212  * using mutex_lock_nested().
1213  *
1214  * NOTE: MUST NOT be called from interrupt context,
1215  * because the bus read/write functions may wait for an interrupt
1216  * to conclude the operation.
1217  */
1218 int mdiobus_c45_write_nested(struct mii_bus *bus, int addr, int devad,
1219 			     u32 regnum, u16 val)
1220 {
1221 	int err;
1222 
1223 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
1224 	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
1225 	mutex_unlock(&bus->mdio_lock);
1226 
1227 	return err;
1228 }
1229 EXPORT_SYMBOL(mdiobus_c45_write_nested);
1230 
1231 /*
1232  * __mdiobus_modify - Convenience function for modifying a given mdio device
1233  *	register
1234  * @bus: the mii_bus struct
1235  * @addr: the phy address
1236  * @regnum: register number to write
1237  * @mask: bit mask of bits to clear
1238  * @set: bit mask of bits to set
1239  */
1240 int __mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask,
1241 		     u16 set)
1242 {
1243 	int err;
1244 
1245 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
1246 
1247 	return err < 0 ? err : 0;
1248 }
1249 EXPORT_SYMBOL_GPL(__mdiobus_modify);
1250 
1251 /**
1252  * mdiobus_modify - Convenience function for modifying a given mdio device
1253  *	register
1254  * @bus: the mii_bus struct
1255  * @addr: the phy address
1256  * @regnum: register number to write
1257  * @mask: bit mask of bits to clear
1258  * @set: bit mask of bits to set
1259  */
1260 int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
1261 {
1262 	int err;
1263 
1264 	mutex_lock(&bus->mdio_lock);
1265 	err = __mdiobus_modify(bus, addr, regnum, mask, set);
1266 	mutex_unlock(&bus->mdio_lock);
1267 
1268 	return err;
1269 }
1270 EXPORT_SYMBOL_GPL(mdiobus_modify);
1271 
1272 /**
1273  * mdiobus_c45_modify - Convenience function for modifying a given mdio device
1274  *	register
1275  * @bus: the mii_bus struct
1276  * @addr: the phy address
1277  * @devad: device address to read
1278  * @regnum: register number to write
1279  * @mask: bit mask of bits to clear
1280  * @set: bit mask of bits to set
1281  */
1282 int mdiobus_c45_modify(struct mii_bus *bus, int addr, int devad, u32 regnum,
1283 		       u16 mask, u16 set)
1284 {
1285 	int err;
1286 
1287 	mutex_lock(&bus->mdio_lock);
1288 	err = __mdiobus_c45_modify_changed(bus, addr, devad, regnum,
1289 					   mask, set);
1290 	mutex_unlock(&bus->mdio_lock);
1291 
1292 	return err < 0 ? err : 0;
1293 }
1294 EXPORT_SYMBOL_GPL(mdiobus_c45_modify);
1295 
1296 /**
1297  * mdiobus_modify_changed - Convenience function for modifying a given mdio
1298  *	device register and returning if it changed
1299  * @bus: the mii_bus struct
1300  * @addr: the phy address
1301  * @regnum: register number to write
1302  * @mask: bit mask of bits to clear
1303  * @set: bit mask of bits to set
1304  */
1305 int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
1306 			   u16 mask, u16 set)
1307 {
1308 	int err;
1309 
1310 	mutex_lock(&bus->mdio_lock);
1311 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
1312 	mutex_unlock(&bus->mdio_lock);
1313 
1314 	return err;
1315 }
1316 EXPORT_SYMBOL_GPL(mdiobus_modify_changed);
1317 
1318 /**
1319  * mdiobus_c45_modify_changed - Convenience function for modifying a given mdio
1320  *	device register and returning if it changed
1321  * @bus: the mii_bus struct
1322  * @addr: the phy address
1323  * @devad: device address to read
1324  * @regnum: register number to write
1325  * @mask: bit mask of bits to clear
1326  * @set: bit mask of bits to set
1327  */
1328 int mdiobus_c45_modify_changed(struct mii_bus *bus, int addr, int devad,
1329 			       u32 regnum, u16 mask, u16 set)
1330 {
1331 	int err;
1332 
1333 	mutex_lock(&bus->mdio_lock);
1334 	err = __mdiobus_c45_modify_changed(bus, addr, devad, regnum, mask, set);
1335 	mutex_unlock(&bus->mdio_lock);
1336 
1337 	return err;
1338 }
1339 EXPORT_SYMBOL_GPL(mdiobus_c45_modify_changed);
1340 
1341 /**
1342  * mdio_bus_match - determine if given MDIO driver supports the given
1343  *		    MDIO device
1344  * @dev: target MDIO device
1345  * @drv: given MDIO driver
1346  *
1347  * Description: Given a MDIO device, and a MDIO driver, return 1 if
1348  *   the driver supports the device.  Otherwise, return 0. This may
1349  *   require calling the devices own match function, since different classes
1350  *   of MDIO devices have different match criteria.
1351  */
1352 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
1353 {
1354 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
1355 	struct mdio_device *mdio = to_mdio_device(dev);
1356 
1357 	/* Both the driver and device must type-match */
1358 	if (!(mdiodrv->mdiodrv.flags & MDIO_DEVICE_IS_PHY) !=
1359 	    !(mdio->flags & MDIO_DEVICE_FLAG_PHY))
1360 		return 0;
1361 
1362 	if (of_driver_match_device(dev, drv))
1363 		return 1;
1364 
1365 	if (mdio->bus_match)
1366 		return mdio->bus_match(dev, drv);
1367 
1368 	return 0;
1369 }
1370 
1371 static int mdio_uevent(const struct device *dev, struct kobj_uevent_env *env)
1372 {
1373 	int rc;
1374 
1375 	/* Some devices have extra OF data and an OF-style MODALIAS */
1376 	rc = of_device_uevent_modalias(dev, env);
1377 	if (rc != -ENODEV)
1378 		return rc;
1379 
1380 	return 0;
1381 }
1382 
1383 static struct attribute *mdio_bus_device_statistics_attrs[] = {
1384 	&dev_attr_mdio_bus_device_transfers.attr.attr,
1385 	&dev_attr_mdio_bus_device_errors.attr.attr,
1386 	&dev_attr_mdio_bus_device_writes.attr.attr,
1387 	&dev_attr_mdio_bus_device_reads.attr.attr,
1388 	NULL,
1389 };
1390 
1391 static const struct attribute_group mdio_bus_device_statistics_group = {
1392 	.name	= "statistics",
1393 	.attrs	= mdio_bus_device_statistics_attrs,
1394 };
1395 
1396 static const struct attribute_group *mdio_bus_dev_groups[] = {
1397 	&mdio_bus_device_statistics_group,
1398 	NULL,
1399 };
1400 
1401 struct bus_type mdio_bus_type = {
1402 	.name		= "mdio_bus",
1403 	.dev_groups	= mdio_bus_dev_groups,
1404 	.match		= mdio_bus_match,
1405 	.uevent		= mdio_uevent,
1406 };
1407 EXPORT_SYMBOL(mdio_bus_type);
1408 
1409 int __init mdio_bus_init(void)
1410 {
1411 	int ret;
1412 
1413 	ret = class_register(&mdio_bus_class);
1414 	if (!ret) {
1415 		ret = bus_register(&mdio_bus_type);
1416 		if (ret)
1417 			class_unregister(&mdio_bus_class);
1418 	}
1419 
1420 	return ret;
1421 }
1422 
1423 #if IS_ENABLED(CONFIG_PHYLIB)
1424 void mdio_bus_exit(void)
1425 {
1426 	class_unregister(&mdio_bus_class);
1427 	bus_unregister(&mdio_bus_type);
1428 }
1429 EXPORT_SYMBOL_GPL(mdio_bus_exit);
1430 #else
1431 module_init(mdio_bus_init);
1432 /* no module_exit, intentional */
1433 MODULE_LICENSE("GPL");
1434 MODULE_DESCRIPTION("MDIO bus/device layer");
1435 #endif
1436