[deliverable/linux.git] / drivers / base / regmap / regcache.c

/*
 * Register cache access API
 *
 * 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/export.h>
#include <trace/events/regmap.h>
#include <linux/bsearch.h>
#include <linux/sort.h>

#include "internal.h"

static const struct regcache_ops *cache_types[] = {
	&regcache_rbtree_ops,
	&regcache_lzo_ops,
};

static int regcache_hw_init(struct regmap *map)
{
	int i, j;
	int ret;
	int count;
	unsigned int val;
	void *tmp_buf;

	if (!map->num_reg_defaults_raw)
		return -EINVAL;

	if (!map->reg_defaults_raw) {
		dev_warn(map->dev, "No cache defaults, reading back from HW\n");
		tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
		if (!tmp_buf)
			return -EINVAL;
		ret = regmap_bulk_read(map, 0, tmp_buf,
				       map->num_reg_defaults_raw);
		if (ret < 0) {
			kfree(tmp_buf);
			return ret;
		}
		map->reg_defaults_raw = tmp_buf;
		map->cache_free = 1;
	}

	/* calculate the size of reg_defaults */
	for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++) {
		val = regcache_get_val(map->reg_defaults_raw,
				       i, map->cache_word_size);
		if (!val)
			continue;
		count++;
	}

	map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
				      GFP_KERNEL);
	if (!map->reg_defaults) {
		ret = -ENOMEM;
		goto err_free;
	}

	/* fill the reg_defaults */
	map->num_reg_defaults = count;
	for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
		val = regcache_get_val(map->reg_defaults_raw,
				       i, map->cache_word_size);
		if (!val)
			continue;
		map->reg_defaults[j].reg = i;
		map->reg_defaults[j].def = val;
		j++;
	}

	return 0;

err_free:
	if (map->cache_free)
		kfree(map->reg_defaults_raw);

	return ret;
}

int regcache_init(struct regmap *map, const struct regmap_config *config)
{
	int ret;
	int i;
	void *tmp_buf;

	if (map->cache_type == REGCACHE_NONE) {
		map->cache_bypass = true;
		return 0;
	}

	for (i = 0; i < ARRAY_SIZE(cache_types); i++)
		if (cache_types[i]->type == map->cache_type)
			break;

	if (i == ARRAY_SIZE(cache_types)) {
		dev_err(map->dev, "Could not match compress type: %d\n",
			map->cache_type);
		return -EINVAL;
	}

	map->num_reg_defaults = config->num_reg_defaults;
	map->num_reg_defaults_raw = config->num_reg_defaults_raw;
	map->reg_defaults_raw = config->reg_defaults_raw;
	map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
	map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;

	map->cache = NULL;
	map->cache_ops = cache_types[i];

	if (!map->cache_ops->read ||
	    !map->cache_ops->write ||
	    !map->cache_ops->name)
		return -EINVAL;

	/* We still need to ensure that the reg_defaults
	 * won't vanish from under us.  We'll need to make
	 * a copy of it.
	 */
	if (config->reg_defaults) {
		if (!map->num_reg_defaults)
			return -EINVAL;
		tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
				  sizeof(struct reg_default), GFP_KERNEL);
		if (!tmp_buf)
			return -ENOMEM;
		map->reg_defaults = tmp_buf;
	} else if (map->num_reg_defaults_raw) {
		/* Some devices such as PMICs don't have cache defaults,
		 * we cope with this by reading back the HW registers and
		 * crafting the cache defaults by hand.
		 */
		ret = regcache_hw_init(map);
		if (ret < 0)
			return ret;
	}

	if (!map->max_register)
		map->max_register = map->num_reg_defaults_raw;

	if (map->cache_ops->init) {
		dev_dbg(map->dev, "Initializing %s cache\n",
			map->cache_ops->name);
		ret = map->cache_ops->init(map);
		if (ret)
			goto err_free;
	}
	return 0;

err_free:
	kfree(map->reg_defaults);
	if (map->cache_free)
		kfree(map->reg_defaults_raw);

	return ret;
}

void regcache_exit(struct regmap *map)
{
	if (map->cache_type == REGCACHE_NONE)
		return;

	BUG_ON(!map->cache_ops);

	kfree(map->reg_defaults);
	if (map->cache_free)
		kfree(map->reg_defaults_raw);

	if (map->cache_ops->exit) {
		dev_dbg(map->dev, "Destroying %s cache\n",
			map->cache_ops->name);
		map->cache_ops->exit(map);
	}
}

/**
 * regcache_read: Fetch the value of a given register from the cache.
 *
 * @map: map to configure.
 * @reg: The register index.
 * @value: The value to be returned.
 *
 * Return a negative value on failure, 0 on success.
 */
int regcache_read(struct regmap *map,
		  unsigned int reg, unsigned int *value)
{
	int ret;

	if (map->cache_type == REGCACHE_NONE)
		return -ENOSYS;

	BUG_ON(!map->cache_ops);

	if (!regmap_volatile(map, reg)) {
		ret = map->cache_ops->read(map, reg, value);

		if (ret == 0)
			trace_regmap_reg_read_cache(map->dev, reg, *value);

		return ret;
	}

	return -EINVAL;
}
EXPORT_SYMBOL_GPL(regcache_read);

/**
 * regcache_write: Set the value of a given register in the cache.
 *
 * @map: map to configure.
 * @reg: The register index.
 * @value: The new register value.
 *
 * Return a negative value on failure, 0 on success.
 */
int regcache_write(struct regmap *map,
		   unsigned int reg, unsigned int value)
{
	if (map->cache_type == REGCACHE_NONE)
		return 0;

	BUG_ON(!map->cache_ops);

	if (!regmap_writeable(map, reg))
		return -EIO;

	if (!regmap_volatile(map, reg))
		return map->cache_ops->write(map, reg, value);

	return 0;
}
EXPORT_SYMBOL_GPL(regcache_write);

/**
 * regcache_sync: Sync the register cache with the hardware.
 *
 * @map: map to configure.
 *
 * Any registers that should not be synced should be marked as
 * volatile.  In general drivers can choose not to use the provided
 * syncing functionality if they so require.
 *
 * Return a negative value on failure, 0 on success.
 */
int regcache_sync(struct regmap *map)
{
	int ret = 0;
	unsigned int i;
	const char *name;
	unsigned int bypass;

	BUG_ON(!map->cache_ops || !map->cache_ops->sync);

	mutex_lock(&map->lock);
	/* Remember the initial bypass state */
	bypass = map->cache_bypass;
	dev_dbg(map->dev, "Syncing %s cache\n",
		map->cache_ops->name);
	name = map->cache_ops->name;
	trace_regcache_sync(map->dev, name, "start");

	if (!map->cache_dirty)
		goto out;

	/* Apply any patch first */
	map->cache_bypass = 1;
	for (i = 0; i < map->patch_regs; i++) {
		ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
		if (ret != 0) {
			dev_err(map->dev, "Failed to write %x = %x: %d\n",
				map->patch[i].reg, map->patch[i].def, ret);
			goto out;
		}
	}
	map->cache_bypass = 0;

	ret = map->cache_ops->sync(map);

out:
	trace_regcache_sync(map->dev, name, "stop");
	/* Restore the bypass state */
	map->cache_bypass = bypass;
	mutex_unlock(&map->lock);

	return ret;
}
EXPORT_SYMBOL_GPL(regcache_sync);

/**
 * regcache_cache_only: Put a register map into cache only mode
 *
 * @map: map to configure
 * @cache_only: flag if changes should be written to the hardware
 *
 * When a register map is marked as cache only writes to the register
 * map API will only update the register cache, they will not cause
 * any hardware changes.  This is useful for allowing portions of
 * drivers to act as though the device were functioning as normal when
 * it is disabled for power saving reasons.
 */
void regcache_cache_only(struct regmap *map, bool enable)
{
	mutex_lock(&map->lock);
	WARN_ON(map->cache_bypass && enable);
	map->cache_only = enable;
	mutex_unlock(&map->lock);
}
EXPORT_SYMBOL_GPL(regcache_cache_only);

/**
 * regcache_mark_dirty: Mark the register cache as dirty
 *
 * @map: map to mark
 *
 * Mark the register cache as dirty, for example due to the device
 * having been powered down for suspend.  If the cache is not marked
 * as dirty then the cache sync will be suppressed.
 */
void regcache_mark_dirty(struct regmap *map)
{
	mutex_lock(&map->lock);
	map->cache_dirty = true;
	mutex_unlock(&map->lock);
}
EXPORT_SYMBOL_GPL(regcache_mark_dirty);

/**
 * regcache_cache_bypass: Put a register map into cache bypass mode
 *
 * @map: map to configure
 * @cache_bypass: flag if changes should not be written to the hardware
 *
 * When a register map is marked with the cache bypass option, writes
 * to the register map API will only update the hardware and not the
 * the cache directly.  This is useful when syncing the cache back to
 * the hardware.
 */
void regcache_cache_bypass(struct regmap *map, bool enable)
{
	mutex_lock(&map->lock);
	WARN_ON(map->cache_only && enable);
	map->cache_bypass = enable;
	mutex_unlock(&map->lock);
}
EXPORT_SYMBOL_GPL(regcache_cache_bypass);

bool regcache_set_val(void *base, unsigned int idx,
		      unsigned int val, unsigned int word_size)
{
	switch (word_size) {
	case 1: {
		u8 *cache = base;
		if (cache[idx] == val)
			return true;
		cache[idx] = val;
		break;
	}
	case 2: {
		u16 *cache = base;
		if (cache[idx] == val)
			return true;
		cache[idx] = val;
		break;
	}
	default:
		BUG();
	}
	/* unreachable */
	return false;
}

unsigned int regcache_get_val(const void *base, unsigned int idx,
			      unsigned int word_size)
{
	if (!base)
		return -EINVAL;

	switch (word_size) {
	case 1: {
		const u8 *cache = base;
		return cache[idx];
	}
	case 2: {
		const u16 *cache = base;
		return cache[idx];
	}
	default:
		BUG();
	}
	/* unreachable */
	return -1;
}

static int regcache_default_cmp(const void *a, const void *b)
{
	const struct reg_default *_a = a;
	const struct reg_default *_b = b;

	return _a->reg - _b->reg;
}

int regcache_lookup_reg(struct regmap *map, unsigned int reg)
{
	struct reg_default key;
	struct reg_default *r;

	key.reg = reg;
	key.def = 0;

	r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
		    sizeof(struct reg_default), regcache_default_cmp);

	if (r)
		return r - map->reg_defaults;
	else
		return -ENOENT;
}
Commit	Line	Data
9fabe24e DP	1	/*
	2	* Register cache access API
	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>
1b6bc32f	14	#include <linux/export.h>
9fabe24e	15	#include <trace/events/regmap.h>
f094fea6	16	#include <linux/bsearch.h>
c08604b8	17	#include <linux/sort.h>
9fabe24e DP	18
	19	#include "internal.h"
	20
	21	static const struct regcache_ops *cache_types[] = {
28644c80	22	&regcache_rbtree_ops,
2cbbb579	23	&regcache_lzo_ops,
9fabe24e DP	24	};
	25
	26	static int regcache_hw_init(struct regmap *map)
	27	{
	28	int i, j;
	29	int ret;
	30	int count;
	31	unsigned int val;
	32	void *tmp_buf;
	33
	34	if (!map->num_reg_defaults_raw)
	35	return -EINVAL;
	36
	37	if (!map->reg_defaults_raw) {
	38	dev_warn(map->dev, "No cache defaults, reading back from HW\n");
	39	tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
	40	if (!tmp_buf)
	41	return -EINVAL;
	42	ret = regmap_bulk_read(map, 0, tmp_buf,
	43	map->num_reg_defaults_raw);
	44	if (ret < 0) {
	45	kfree(tmp_buf);
	46	return ret;
	47	}
	48	map->reg_defaults_raw = tmp_buf;
	49	map->cache_free = 1;
	50	}
	51
	52	/* calculate the size of reg_defaults */
	53	for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++) {
	54	val = regcache_get_val(map->reg_defaults_raw,
	55	i, map->cache_word_size);
	56	if (!val)
	57	continue;
	58	count++;
	59	}
	60
	61	map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
	62	GFP_KERNEL);
021cd616 LPC	63	if (!map->reg_defaults) {
	64	ret = -ENOMEM;
	65	goto err_free;
	66	}
9fabe24e DP	67
	68	/* fill the reg_defaults */
	69	map->num_reg_defaults = count;
	70	for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
	71	val = regcache_get_val(map->reg_defaults_raw,
	72	i, map->cache_word_size);
	73	if (!val)
	74	continue;
	75	map->reg_defaults[j].reg = i;
	76	map->reg_defaults[j].def = val;
	77	j++;
	78	}
	79
	80	return 0;
021cd616 LPC	81
	82	err_free:
	83	if (map->cache_free)
	84	kfree(map->reg_defaults_raw);
	85
	86	return ret;
9fabe24e DP	87	}
9fabe24e DP	88
e5e3b8ab	89	int regcache_init(struct regmap map, const struct regmap_config config)
9fabe24e DP	90	{
	91	int ret;
	92	int i;
	93	void *tmp_buf;
	94
e7a6db30 MB	95	if (map->cache_type == REGCACHE_NONE) {
e7a6db30 MB	96	map->cache_bypass = true;
9fabe24e	97	return 0;
e7a6db30	98	}
9fabe24e DP	99
	100	for (i = 0; i < ARRAY_SIZE(cache_types); i++)
	101	if (cache_types[i]->type == map->cache_type)
	102	break;
	103
	104	if (i == ARRAY_SIZE(cache_types)) {
	105	dev_err(map->dev, "Could not match compress type: %d\n",
	106	map->cache_type);
	107	return -EINVAL;
	108	}
	109
e5e3b8ab LPC	110	map->num_reg_defaults = config->num_reg_defaults;
	111	map->num_reg_defaults_raw = config->num_reg_defaults_raw;
	112	map->reg_defaults_raw = config->reg_defaults_raw;
064d4db1 LPC	113	map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
064d4db1 LPC	114	map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
e5e3b8ab	115
9fabe24e DP	116	map->cache = NULL;
	117	map->cache_ops = cache_types[i];
	118
	119	if (!map->cache_ops->read \|\|
	120	!map->cache_ops->write \|\|
	121	!map->cache_ops->name)
	122	return -EINVAL;
	123
	124	/* We still need to ensure that the reg_defaults
	125	* won't vanish from under us. We'll need to make
	126	* a copy of it.
	127	*/
720e4616	128	if (config->reg_defaults) {
9fabe24e DP	129	if (!map->num_reg_defaults)
9fabe24e DP	130	return -EINVAL;
720e4616	131	tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
9fabe24e DP	132	sizeof(struct reg_default), GFP_KERNEL);
	133	if (!tmp_buf)
	134	return -ENOMEM;
	135	map->reg_defaults = tmp_buf;
8528bdd4	136	} else if (map->num_reg_defaults_raw) {
5fcd2560	137	/* Some devices such as PMICs don't have cache defaults,
9fabe24e DP	138	* we cope with this by reading back the HW registers and
	139	* crafting the cache defaults by hand.
	140	*/
	141	ret = regcache_hw_init(map);
	142	if (ret < 0)
	143	return ret;
	144	}
	145
	146	if (!map->max_register)
	147	map->max_register = map->num_reg_defaults_raw;
	148
	149	if (map->cache_ops->init) {
	150	dev_dbg(map->dev, "Initializing %s cache\n",
	151	map->cache_ops->name);
bd061c78 LPC	152	ret = map->cache_ops->init(map);
	153	if (ret)
	154	goto err_free;
9fabe24e DP	155	}
9fabe24e DP	156	return 0;
bd061c78 LPC	157
	158	err_free:
	159	kfree(map->reg_defaults);
	160	if (map->cache_free)
	161	kfree(map->reg_defaults_raw);
	162
	163	return ret;
9fabe24e DP	164	}
	165
	166	void regcache_exit(struct regmap *map)
	167	{
	168	if (map->cache_type == REGCACHE_NONE)
	169	return;
	170
	171	BUG_ON(!map->cache_ops);
	172
	173	kfree(map->reg_defaults);
	174	if (map->cache_free)
	175	kfree(map->reg_defaults_raw);
	176
	177	if (map->cache_ops->exit) {
	178	dev_dbg(map->dev, "Destroying %s cache\n",
	179	map->cache_ops->name);
	180	map->cache_ops->exit(map);
	181	}
	182	}
	183
	184	/**
	185	* regcache_read: Fetch the value of a given register from the cache.
	186	*
	187	* @map: map to configure.
	188	* @reg: The register index.
	189	* @value: The value to be returned.
	190	*
	191	* Return a negative value on failure, 0 on success.
	192	*/
	193	int regcache_read(struct regmap *map,
	194	unsigned int reg, unsigned int *value)
	195	{
bc7ee556 MB	196	int ret;
bc7ee556 MB	197
9fabe24e DP	198	if (map->cache_type == REGCACHE_NONE)
	199	return -ENOSYS;
	200
	201	BUG_ON(!map->cache_ops);
	202
bc7ee556 MB	203	if (!regmap_volatile(map, reg)) {
	204	ret = map->cache_ops->read(map, reg, value);
	205
	206	if (ret == 0)
	207	trace_regmap_reg_read_cache(map->dev, reg, *value);
	208
	209	return ret;
	210	}
9fabe24e DP	211
	212	return -EINVAL;
	213	}
	214	EXPORT_SYMBOL_GPL(regcache_read);
	215
	216	/**
	217	* regcache_write: Set the value of a given register in the cache.
	218	*
	219	* @map: map to configure.
	220	* @reg: The register index.
	221	* @value: The new register value.
	222	*
	223	* Return a negative value on failure, 0 on success.
	224	*/
	225	int regcache_write(struct regmap *map,
	226	unsigned int reg, unsigned int value)
	227	{
	228	if (map->cache_type == REGCACHE_NONE)
	229	return 0;
	230
	231	BUG_ON(!map->cache_ops);
	232
	233	if (!regmap_writeable(map, reg))
	234	return -EIO;
	235
	236	if (!regmap_volatile(map, reg))
	237	return map->cache_ops->write(map, reg, value);
	238
	239	return 0;
	240	}
	241	EXPORT_SYMBOL_GPL(regcache_write);
	242
	243	/**
	244	* regcache_sync: Sync the register cache with the hardware.
	245	*
	246	* @map: map to configure.
	247	*
	248	* Any registers that should not be synced should be marked as
	249	* volatile. In general drivers can choose not to use the provided
	250	* syncing functionality if they so require.
	251	*
	252	* Return a negative value on failure, 0 on success.
	253	*/
	254	int regcache_sync(struct regmap *map)
	255	{
954757d7	256	int ret = 0;
954757d7	257	unsigned int i;
59360089	258	const char *name;
beb1a10f	259	unsigned int bypass;
59360089	260
c3ec2328	261	BUG_ON(!map->cache_ops \|\| !map->cache_ops->sync);
9fabe24e	262
13753a90	263	mutex_lock(&map->lock);
beb1a10f DP	264	/* Remember the initial bypass state */
beb1a10f DP	265	bypass = map->cache_bypass;
954757d7 DP	266	dev_dbg(map->dev, "Syncing %s cache\n",
	267	map->cache_ops->name);
	268	name = map->cache_ops->name;
	269	trace_regcache_sync(map->dev, name, "start");
22f0d90a	270
d9db7627 MB	271	if (!map->cache_dirty)
	272	goto out;
	273
22f0d90a	274	/* Apply any patch first */
8a892d69	275	map->cache_bypass = 1;
22f0d90a MB	276	for (i = 0; i < map->patch_regs; i++) {
	277	ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
	278	if (ret != 0) {
	279	dev_err(map->dev, "Failed to write %x = %x: %d\n",
	280	map->patch[i].reg, map->patch[i].def, ret);
	281	goto out;
	282	}
	283	}
8a892d69	284	map->cache_bypass = 0;
22f0d90a	285
c3ec2328	286	ret = map->cache_ops->sync(map);
954757d7	287
954757d7 DP	288	out:
954757d7 DP	289	trace_regcache_sync(map->dev, name, "stop");
beb1a10f DP	290	/* Restore the bypass state */
beb1a10f DP	291	map->cache_bypass = bypass;
13753a90	292	mutex_unlock(&map->lock);
954757d7 DP	293
954757d7 DP	294	return ret;
9fabe24e DP	295	}
	296	EXPORT_SYMBOL_GPL(regcache_sync);
	297
92afb286 MB	298	/**
	299	* regcache_cache_only: Put a register map into cache only mode
	300	*
	301	* @map: map to configure
	302	* @cache_only: flag if changes should be written to the hardware
	303	*
	304	* When a register map is marked as cache only writes to the register
	305	* map API will only update the register cache, they will not cause
	306	* any hardware changes. This is useful for allowing portions of
	307	* drivers to act as though the device were functioning as normal when
	308	* it is disabled for power saving reasons.
	309	*/
	310	void regcache_cache_only(struct regmap *map, bool enable)
	311	{
2cd148f1	312	mutex_lock(&map->lock);
ac77a765	313	WARN_ON(map->cache_bypass && enable);
92afb286	314	map->cache_only = enable;
2cd148f1	315	mutex_unlock(&map->lock);
92afb286 MB	316	}
	317	EXPORT_SYMBOL_GPL(regcache_cache_only);
	318
8ae0d7e8 MB	319	/**
	320	* regcache_mark_dirty: Mark the register cache as dirty
	321	*
	322	* @map: map to mark
	323	*
	324	* Mark the register cache as dirty, for example due to the device
	325	* having been powered down for suspend. If the cache is not marked
	326	* as dirty then the cache sync will be suppressed.
	327	*/
	328	void regcache_mark_dirty(struct regmap *map)
	329	{
	330	mutex_lock(&map->lock);
	331	map->cache_dirty = true;
	332	mutex_unlock(&map->lock);
	333	}
	334	EXPORT_SYMBOL_GPL(regcache_mark_dirty);
	335
6eb0f5e0 DP	336	/**
	337	* regcache_cache_bypass: Put a register map into cache bypass mode
	338	*
	339	* @map: map to configure
0eef6b04	340	* @cache_bypass: flag if changes should not be written to the hardware
6eb0f5e0 DP	341	*
	342	* When a register map is marked with the cache bypass option, writes
	343	* to the register map API will only update the hardware and not the
	344	* the cache directly. This is useful when syncing the cache back to
	345	* the hardware.
	346	*/
	347	void regcache_cache_bypass(struct regmap *map, bool enable)
	348	{
	349	mutex_lock(&map->lock);
ac77a765	350	WARN_ON(map->cache_only && enable);
6eb0f5e0 DP	351	map->cache_bypass = enable;
	352	mutex_unlock(&map->lock);
	353	}
	354	EXPORT_SYMBOL_GPL(regcache_cache_bypass);
	355
9fabe24e DP	356	bool regcache_set_val(void *base, unsigned int idx,
	357	unsigned int val, unsigned int word_size)
	358	{
	359	switch (word_size) {
	360	case 1: {
	361	u8 *cache = base;
	362	if (cache[idx] == val)
	363	return true;
	364	cache[idx] = val;
	365	break;
	366	}
	367	case 2: {
	368	u16 *cache = base;
	369	if (cache[idx] == val)
	370	return true;
	371	cache[idx] = val;
	372	break;
	373	}
	374	default:
	375	BUG();
	376	}
	377	/* unreachable */
	378	return false;
	379	}
	380
	381	unsigned int regcache_get_val(const void *base, unsigned int idx,
	382	unsigned int word_size)
	383	{
	384	if (!base)
	385	return -EINVAL;
	386
	387	switch (word_size) {
	388	case 1: {
	389	const u8 *cache = base;
	390	return cache[idx];
	391	}
	392	case 2: {
	393	const u16 *cache = base;
	394	return cache[idx];
	395	}
	396	default:
	397	BUG();
	398	}
	399	/* unreachable */
	400	return -1;
	401	}
	402
f094fea6	403	static int regcache_default_cmp(const void a, const void b)
c08604b8 DP	404	{
	405	const struct reg_default *_a = a;
	406	const struct reg_default *_b = b;
	407
	408	return _a->reg - _b->reg;
	409	}
	410
f094fea6 MB	411	int regcache_lookup_reg(struct regmap *map, unsigned int reg)
	412	{
	413	struct reg_default key;
	414	struct reg_default *r;
	415
	416	key.reg = reg;
	417	key.def = 0;
	418
	419	r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
	420	sizeof(struct reg_default), regcache_default_cmp);
	421
	422	if (r)
	423	return r - map->reg_defaults;
	424	else
6e6ace00	425	return -ENOENT;
f094fea6	426	}