[mirror_ubuntu-artful-kernel.git] / drivers / base / regmap / regcache-rbtree.c

/*
 * Register cache access API - rbtree caching support
 *
 * Copyright 2011 Wolfson Microelectronics plc
 *
 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/slab.h>
#include <linux/rbtree.h>

#include "internal.h"

static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
				 unsigned int value);

struct regcache_rbtree_node {
	/* the actual rbtree node holding this block */
	struct rb_node node;
	/* base register handled by this block */
	unsigned int base_reg;
	/* number of bytes needed to represent the register index */
	unsigned int word_size;
	/* block of adjacent registers */
	void *block;
	/* number of registers available in the block */
	unsigned int blklen;
} __attribute__ ((packed));

struct regcache_rbtree_ctx {
	struct rb_root root;
	struct regcache_rbtree_node *cached_rbnode;
};

static inline void regcache_rbtree_get_base_top_reg(
	struct regcache_rbtree_node *rbnode,
	unsigned int *base, unsigned int *top)
{
	*base = rbnode->base_reg;
	*top = rbnode->base_reg + rbnode->blklen - 1;
}

static unsigned int regcache_rbtree_get_register(
	struct regcache_rbtree_node *rbnode, unsigned int idx)
{
	unsigned int val;

	switch (rbnode->word_size) {
	case 1: {
		u8 *p = rbnode->block;
		val = p[idx];
		return val;
	}
	case 2: {
		u16 *p = rbnode->block;
		val = p[idx];
		return val;
	}
	default:
		BUG();
		break;
	}
	return -1;
}

static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
					 unsigned int idx, unsigned int val)
{
	switch (rbnode->word_size) {
	case 1: {
		u8 *p = rbnode->block;
		p[idx] = val;
		break;
	}
	case 2: {
		u16 *p = rbnode->block;
		p[idx] = val;
		break;
	}
	default:
		BUG();
		break;
	}
}

static struct regcache_rbtree_node *regcache_rbtree_lookup(
	struct rb_root *root, unsigned int reg)
{
	struct rb_node *node;
	struct regcache_rbtree_node *rbnode;
	unsigned int base_reg, top_reg;

	node = root->rb_node;
	while (node) {
		rbnode = container_of(node, struct regcache_rbtree_node, node);
		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
		if (reg >= base_reg && reg <= top_reg)
			return rbnode;
		else if (reg > top_reg)
			node = node->rb_right;
		else if (reg < base_reg)
			node = node->rb_left;
	}

	return NULL;
}

static int regcache_rbtree_insert(struct rb_root *root,
				  struct regcache_rbtree_node *rbnode)
{
	struct rb_node **new, *parent;
	struct regcache_rbtree_node *rbnode_tmp;
	unsigned int base_reg_tmp, top_reg_tmp;
	unsigned int base_reg;

	parent = NULL;
	new = &root->rb_node;
	while (*new) {
		rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
					  node);
		/* base and top registers of the current rbnode */
		regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
						 &top_reg_tmp);
		/* base register of the rbnode to be added */
		base_reg = rbnode->base_reg;
		parent = *new;
		/* if this register has already been inserted, just return */
		if (base_reg >= base_reg_tmp &&
		    base_reg <= top_reg_tmp)
			return 0;
		else if (base_reg > top_reg_tmp)
			new = &((*new)->rb_right);
		else if (base_reg < base_reg_tmp)
			new = &((*new)->rb_left);
	}

	/* insert the node into the rbtree */
	rb_link_node(&rbnode->node, parent, new);
	rb_insert_color(&rbnode->node, root);

	return 1;
}

static int regcache_rbtree_init(struct regmap *map)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	int i;
	int ret;

	map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
	if (!map->cache)
		return -ENOMEM;

	rbtree_ctx = map->cache;
	rbtree_ctx->root = RB_ROOT;
	rbtree_ctx->cached_rbnode = NULL;

	for (i = 0; i < map->num_reg_defaults; i++) {
		ret = regcache_rbtree_write(map,
					    map->reg_defaults[i].reg,
					    map->reg_defaults[i].def);
		if (ret)
			goto err;
	}

	return 0;

err:
	regcache_exit(map);
	return ret;
}

static int regcache_rbtree_exit(struct regmap *map)
{
	struct rb_node *next;
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct regcache_rbtree_node *rbtree_node;

	/* if we've already been called then just return */
	rbtree_ctx = map->cache;
	if (!rbtree_ctx)
		return 0;

	/* free up the rbtree */
	next = rb_first(&rbtree_ctx->root);
	while (next) {
		rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
		next = rb_next(&rbtree_node->node);
		rb_erase(&rbtree_node->node, &rbtree_ctx->root);
		kfree(rbtree_node->block);
		kfree(rbtree_node);
	}

	/* release the resources */
	kfree(map->cache);
	map->cache = NULL;

	return 0;
}

static int regcache_rbtree_read(struct regmap *map,
				unsigned int reg, unsigned int *value)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct regcache_rbtree_node *rbnode;
	unsigned int base_reg, top_reg;
	unsigned int reg_tmp;

	rbtree_ctx = map->cache;
	/* look up the required register in the cached rbnode */
	rbnode = rbtree_ctx->cached_rbnode;
	if (rbnode) {
		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
		if (reg >= base_reg && reg <= top_reg) {
			reg_tmp = reg - base_reg;
			*value = regcache_rbtree_get_register(rbnode, reg_tmp);
			return 0;
		}
	}
	/* if we can't locate it in the cached rbnode we'll have
	 * to traverse the rbtree looking for it.
	 */
	rbnode = regcache_rbtree_lookup(&rbtree_ctx->root, reg);
	if (rbnode) {
		reg_tmp = reg - rbnode->base_reg;
		*value = regcache_rbtree_get_register(rbnode, reg_tmp);
		rbtree_ctx->cached_rbnode = rbnode;
	} else {
		/* uninitialized registers default to 0 */
		*value = 0;
	}

	return 0;
}


static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
					   unsigned int pos, unsigned int reg,
					   unsigned int value)
{
	u8 *blk;

	blk = krealloc(rbnode->block,
		       (rbnode->blklen + 1) * rbnode->word_size, GFP_KERNEL);
	if (!blk)
		return -ENOMEM;

	/* insert the register value in the correct place in the rbnode block */
	memmove(blk + (pos + 1) * rbnode->word_size,
		blk + pos * rbnode->word_size,
		(rbnode->blklen - pos) * rbnode->word_size);

	/* update the rbnode block, its size and the base register */
	rbnode->block = blk;
	rbnode->blklen++;
	if (!pos)
		rbnode->base_reg = reg;

	regcache_rbtree_set_register(rbnode, pos, value);
	return 0;
}

static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
				 unsigned int value)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct regcache_rbtree_node *rbnode, *rbnode_tmp;
	struct rb_node *node;
	unsigned int val;
	unsigned int reg_tmp;
	unsigned int base_reg, top_reg;
	unsigned int pos;
	int i;
	int ret;

	rbtree_ctx = map->cache;
	/* look up the required register in the cached rbnode */
	rbnode = rbtree_ctx->cached_rbnode;
	if (rbnode) {
		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
		if (reg >= base_reg && reg <= top_reg) {
			reg_tmp = reg - base_reg;
			val = regcache_rbtree_get_register(rbnode, reg_tmp);
			if (val == value)
				return 0;
			regcache_rbtree_set_register(rbnode, reg_tmp, value);
			return 0;
		}
	}
	/* if we can't locate it in the cached rbnode we'll have
	 * to traverse the rbtree looking for it.
	 */
	rbnode = regcache_rbtree_lookup(&rbtree_ctx->root, reg);
	if (rbnode) {
		reg_tmp = reg - rbnode->base_reg;
		val = regcache_rbtree_get_register(rbnode, reg_tmp);
		if (val == value)
			return 0;
		regcache_rbtree_set_register(rbnode, reg_tmp, value);
		rbtree_ctx->cached_rbnode = rbnode;
	} else {
		/* bail out early, no need to create the rbnode yet */
		if (!value)
			return 0;
		/* look for an adjacent register to the one we are about to add */
		for (node = rb_first(&rbtree_ctx->root); node;
		     node = rb_next(node)) {
			rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
			for (i = 0; i < rbnode_tmp->blklen; i++) {
				reg_tmp = rbnode_tmp->base_reg + i;
				if (abs(reg_tmp - reg) != 1)
					continue;
				/* decide where in the block to place our register */
				if (reg_tmp + 1 == reg)
					pos = i + 1;
				else
					pos = i;
				ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
								      reg, value);
				if (ret)
					return ret;
				rbtree_ctx->cached_rbnode = rbnode_tmp;
				return 0;
			}
		}
		/* we did not manage to find a place to insert it in an existing
		 * block so create a new rbnode with a single register in its block.
		 * This block will get populated further if any other adjacent
		 * registers get modified in the future.
		 */
		rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
		if (!rbnode)
			return -ENOMEM;
		rbnode->blklen = 1;
		rbnode->base_reg = reg;
		rbnode->word_size = map->cache_word_size;
		rbnode->block = kmalloc(rbnode->blklen * rbnode->word_size,
					GFP_KERNEL);
		if (!rbnode->block) {
			kfree(rbnode);
			return -ENOMEM;
		}
		regcache_rbtree_set_register(rbnode, 0, value);
		regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
		rbtree_ctx->cached_rbnode = rbnode;
	}

	return 0;
}

static int regcache_rbtree_sync(struct regmap *map)
{
	struct regcache_rbtree_ctx *rbtree_ctx;
	struct rb_node *node;
	struct regcache_rbtree_node *rbnode;
	unsigned int regtmp;
	unsigned int val, def;
	int ret;
	int i;

	rbtree_ctx = map->cache;
	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
		rbnode = rb_entry(node, struct regcache_rbtree_node, node);
		for (i = 0; i < rbnode->blklen; i++) {
			regtmp = rbnode->base_reg + i;
			val = regcache_rbtree_get_register(rbnode, i);
			ret = regcache_lookup_reg(map, i);
			if (ret < 0)
				def = 0;
			else
				def = map->reg_defaults[ret].def;
			if (val == def)
				continue;
			map->cache_bypass = 1;
			ret = regmap_write(map, regtmp, val);
			map->cache_bypass = 0;
			if (ret)
				return ret;
			dev_dbg(map->dev, "Synced register %#x, value %#x\n",
				regtmp, val);
		}
	}

	return 0;
}

struct regcache_ops regcache_rbtree_ops = {
	.type = REGCACHE_RBTREE,
	.name = "rbtree",
	.init = regcache_rbtree_init,
	.exit = regcache_rbtree_exit,
	.read = regcache_rbtree_read,
	.write = regcache_rbtree_write,
	.sync = regcache_rbtree_sync
};
Commit	Line	Data
28644c80 DP	1	/*
	2	* Register cache access API - rbtree caching support
	3	*
	4	* Copyright 2011 Wolfson Microelectronics plc
	5	*
	6	* Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/slab.h>
	14	#include <linux/rbtree.h>
	15
	16	#include "internal.h"
	17
	18	static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
	19	unsigned int value);
	20
	21	struct regcache_rbtree_node {
	22	/* the actual rbtree node holding this block */
	23	struct rb_node node;
	24	/* base register handled by this block */
	25	unsigned int base_reg;
	26	/* number of bytes needed to represent the register index */
	27	unsigned int word_size;
	28	/* block of adjacent registers */
	29	void *block;
	30	/* number of registers available in the block */
	31	unsigned int blklen;
	32	} __attribute__ ((packed));
	33
	34	struct regcache_rbtree_ctx {
	35	struct rb_root root;
	36	struct regcache_rbtree_node *cached_rbnode;
	37	};
	38
	39	static inline void regcache_rbtree_get_base_top_reg(
	40	struct regcache_rbtree_node *rbnode,
	41	unsigned int base, unsigned int top)
	42	{
	43	*base = rbnode->base_reg;
	44	*top = rbnode->base_reg + rbnode->blklen - 1;
	45	}
	46
	47	static unsigned int regcache_rbtree_get_register(
	48	struct regcache_rbtree_node *rbnode, unsigned int idx)
	49	{
	50	unsigned int val;
	51
	52	switch (rbnode->word_size) {
	53	case 1: {
	54	u8 *p = rbnode->block;
	55	val = p[idx];
	56	return val;
	57	}
	58	case 2: {
	59	u16 *p = rbnode->block;
	60	val = p[idx];
	61	return val;
	62	}
	63	default:
	64	BUG();
65	break;
66	}
67	return -1;
68	}
69
70	static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
71	unsigned int idx, unsigned int val)
72	{
73	switch (rbnode->word_size) {
74	case 1: {
75	u8 *p = rbnode->block;
76	p[idx] = val;
77	break;
78	}
79	case 2: {
80	u16 *p = rbnode->block;
81	p[idx] = val;
82	break;
83	}
84	default:
85	BUG();
86	break;
87	}
88	}
89
90	static struct regcache_rbtree_node *regcache_rbtree_lookup(
91	struct rb_root *root, unsigned int reg)
92	{
93	struct rb_node *node;
94	struct regcache_rbtree_node *rbnode;
95	unsigned int base_reg, top_reg;
96
97	node = root->rb_node;
98	while (node) {
99	rbnode = container_of(node, struct regcache_rbtree_node, node);
100	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
101	if (reg >= base_reg && reg <= top_reg)
102	return rbnode;
103	else if (reg > top_reg)
104	node = node->rb_right;
105	else if (reg < base_reg)
106	node = node->rb_left;
107	}
108
109	return NULL;
110	}
111
112	static int regcache_rbtree_insert(struct rb_root *root,
113	struct regcache_rbtree_node *rbnode)
114	{
115	struct rb_node *new, parent;
116	struct regcache_rbtree_node *rbnode_tmp;
117	unsigned int base_reg_tmp, top_reg_tmp;
118	unsigned int base_reg;
119
120	parent = NULL;
121	new = &root->rb_node;
122	while (*new) {
123	rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
124	node);
125	/* base and top registers of the current rbnode */
126	regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
127	&top_reg_tmp);
128	/* base register of the rbnode to be added */
129	base_reg = rbnode->base_reg;
130	parent = *new;
131	/* if this register has already been inserted, just return */
132	if (base_reg >= base_reg_tmp &&
133	base_reg <= top_reg_tmp)
134	return 0;
135	else if (base_reg > top_reg_tmp)
136	new = &((*new)->rb_right);
137	else if (base_reg < base_reg_tmp)
138	new = &((*new)->rb_left);
139	}
140
141	/* insert the node into the rbtree */
142	rb_link_node(&rbnode->node, parent, new);
143	rb_insert_color(&rbnode->node, root);
144
145	return 1;
146	}
147
148	static int regcache_rbtree_init(struct regmap *map)
149	{
150	struct regcache_rbtree_ctx *rbtree_ctx;
151	int i;
152	int ret;
153
154	map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
155	if (!map->cache)
156	return -ENOMEM;
157
158	rbtree_ctx = map->cache;
159	rbtree_ctx->root = RB_ROOT;
160	rbtree_ctx->cached_rbnode = NULL;
161
162	for (i = 0; i < map->num_reg_defaults; i++) {
163	ret = regcache_rbtree_write(map,
164	map->reg_defaults[i].reg,
165	map->reg_defaults[i].def);
166	if (ret)
167	goto err;
168	}
169
170	return 0;
171
172	err:
173	regcache_exit(map);
174	return ret;
175	}
176
177	static int regcache_rbtree_exit(struct regmap *map)
178	{
179	struct rb_node *next;
180	struct regcache_rbtree_ctx *rbtree_ctx;
181	struct regcache_rbtree_node *rbtree_node;
182
183	/* if we've already been called then just return */
184	rbtree_ctx = map->cache;
185	if (!rbtree_ctx)
186	return 0;
187
188	/* free up the rbtree */
189	next = rb_first(&rbtree_ctx->root);
190	while (next) {
191	rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
192	next = rb_next(&rbtree_node->node);
193	rb_erase(&rbtree_node->node, &rbtree_ctx->root);
194	kfree(rbtree_node->block);
195	kfree(rbtree_node);
196	}
197
198	/* release the resources */
199	kfree(map->cache);
200	map->cache = NULL;
201
202	return 0;
203	}
204
205	static int regcache_rbtree_read(struct regmap *map,
206	unsigned int reg, unsigned int *value)
207	{
208	struct regcache_rbtree_ctx *rbtree_ctx;
209	struct regcache_rbtree_node *rbnode;
210	unsigned int base_reg, top_reg;
211	unsigned int reg_tmp;
212
213	rbtree_ctx = map->cache;
214	/* look up the required register in the cached rbnode */
215	rbnode = rbtree_ctx->cached_rbnode;
216	if (rbnode) {
217	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
218	if (reg >= base_reg && reg <= top_reg) {
219	reg_tmp = reg - base_reg;
220	*value = regcache_rbtree_get_register(rbnode, reg_tmp);
221	return 0;
222	}
223	}
224	/* if we can't locate it in the cached rbnode we'll have
225	* to traverse the rbtree looking for it.
226	*/
227	rbnode = regcache_rbtree_lookup(&rbtree_ctx->root, reg);
228	if (rbnode) {
229	reg_tmp = reg - rbnode->base_reg;
230	*value = regcache_rbtree_get_register(rbnode, reg_tmp);
231	rbtree_ctx->cached_rbnode = rbnode;
232	} else {
233	/* uninitialized registers default to 0 */
234	*value = 0;
235	}
236
237	return 0;
238	}
239
240
241	static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
242	unsigned int pos, unsigned int reg,
243	unsigned int value)
244	{
245	u8 *blk;
246
247	blk = krealloc(rbnode->block,
248	(rbnode->blklen + 1) * rbnode->word_size, GFP_KERNEL);
249	if (!blk)
250	return -ENOMEM;
251
252	/* insert the register value in the correct place in the rbnode block */
253	memmove(blk + (pos + 1) * rbnode->word_size,
254	blk + pos * rbnode->word_size,
255	(rbnode->blklen - pos) * rbnode->word_size);
256
257	/* update the rbnode block, its size and the base register */
258	rbnode->block = blk;
259	rbnode->blklen++;
260	if (!pos)
261	rbnode->base_reg = reg;
262
263	regcache_rbtree_set_register(rbnode, pos, value);
264	return 0;
265	}
266
267	static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
268	unsigned int value)
269	{
270	struct regcache_rbtree_ctx *rbtree_ctx;
271	struct regcache_rbtree_node rbnode, rbnode_tmp;
272	struct rb_node *node;
273	unsigned int val;
274	unsigned int reg_tmp;
275	unsigned int base_reg, top_reg;
276	unsigned int pos;
277	int i;
278	int ret;
279
280	rbtree_ctx = map->cache;
281	/* look up the required register in the cached rbnode */
282	rbnode = rbtree_ctx->cached_rbnode;
283	if (rbnode) {
284	regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
285	if (reg >= base_reg && reg <= top_reg) {
286	reg_tmp = reg - base_reg;
287	val = regcache_rbtree_get_register(rbnode, reg_tmp);
288	if (val == value)
289	return 0;
290	regcache_rbtree_set_register(rbnode, reg_tmp, value);
291	return 0;
292	}
293	}
294	/* if we can't locate it in the cached rbnode we'll have
295	* to traverse the rbtree looking for it.
296	*/
297	rbnode = regcache_rbtree_lookup(&rbtree_ctx->root, reg);
298	if (rbnode) {
299	reg_tmp = reg - rbnode->base_reg;
300	val = regcache_rbtree_get_register(rbnode, reg_tmp);
301	if (val == value)
302	return 0;
303	regcache_rbtree_set_register(rbnode, reg_tmp, value);
304	rbtree_ctx->cached_rbnode = rbnode;
305	} else {
306	/* bail out early, no need to create the rbnode yet */
307	if (!value)
308	return 0;
309	/* look for an adjacent register to the one we are about to add */
310	for (node = rb_first(&rbtree_ctx->root); node;
311	node = rb_next(node)) {
312	rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
313	for (i = 0; i < rbnode_tmp->blklen; i++) {
314	reg_tmp = rbnode_tmp->base_reg + i;
315	if (abs(reg_tmp - reg) != 1)
316	continue;
317	/* decide where in the block to place our register */
318	if (reg_tmp + 1 == reg)
319	pos = i + 1;
320	else
321	pos = i;
322	ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
323	reg, value);
324	if (ret)
325	return ret;
326	rbtree_ctx->cached_rbnode = rbnode_tmp;
327	return 0;
328	}
329	}
330	/* we did not manage to find a place to insert it in an existing
331	* block so create a new rbnode with a single register in its block.
332	* This block will get populated further if any other adjacent
333	* registers get modified in the future.
334	*/
335	rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
336	if (!rbnode)
337	return -ENOMEM;
338	rbnode->blklen = 1;
339	rbnode->base_reg = reg;
340	rbnode->word_size = map->cache_word_size;
341	rbnode->block = kmalloc(rbnode->blklen * rbnode->word_size,
342	GFP_KERNEL);
343	if (!rbnode->block) {
344	kfree(rbnode);
345	return -ENOMEM;
346	}
347	regcache_rbtree_set_register(rbnode, 0, value);
348	regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
349	rbtree_ctx->cached_rbnode = rbnode;
350	}
351
352	return 0;
353	}
354
355	static int regcache_rbtree_sync(struct regmap *map)
356	{
357	struct regcache_rbtree_ctx *rbtree_ctx;
358	struct rb_node *node;
359	struct regcache_rbtree_node *rbnode;
360	unsigned int regtmp;
361	unsigned int val, def;
362	int ret;
363	int i;
364
365	rbtree_ctx = map->cache;
366	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
367	rbnode = rb_entry(node, struct regcache_rbtree_node, node);
368	for (i = 0; i < rbnode->blklen; i++) {
369	regtmp = rbnode->base_reg + i;
370	val = regcache_rbtree_get_register(rbnode, i);
371	ret = regcache_lookup_reg(map, i);
372	if (ret < 0)
373	def = 0;
374	else
375	def = map->reg_defaults[ret].def;
376	if (val == def)
377	continue;
378	map->cache_bypass = 1;
379	ret = regmap_write(map, regtmp, val);
380	map->cache_bypass = 0;
381	if (ret)
382	return ret;
383	dev_dbg(map->dev, "Synced register %#x, value %#x\n",
384	regtmp, val);
385	}
386	}
387
388	return 0;
389	}
390
391	struct regcache_ops regcache_rbtree_ops = {
392	.type = REGCACHE_RBTREE,
393	.name = "rbtree",
394	.init = regcache_rbtree_init,
395	.exit = regcache_rbtree_exit,
396	.read = regcache_rbtree_read,
397	.write = regcache_rbtree_write,
398	.sync = regcache_rbtree_sync
399	};