2 * Register cache access API
4 * Copyright 2011 Wolfson Microelectronics plc
6 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
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.
13 #include <linux/slab.h>
14 #include <linux/export.h>
15 #include <trace/events/regmap.h>
16 #include <linux/bsearch.h>
17 #include <linux/sort.h>
21 static const struct regcache_ops *cache_types[] = {
26 static int regcache_hw_init(struct regmap *map)
34 if (!map->num_reg_defaults_raw)
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);
42 ret = regmap_bulk_read(map, 0, tmp_buf,
43 map->num_reg_defaults_raw);
48 map->reg_defaults_raw = tmp_buf;
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);
61 map->reg_defaults = kmalloc(count * sizeof(struct reg_default),
63 if (!map->reg_defaults) {
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);
75 map->reg_defaults[j].reg = i;
76 map->reg_defaults[j].def = val;
84 kfree(map->reg_defaults_raw);
89 int regcache_init(struct regmap *map, const struct regmap_config *config)
95 if (map->cache_type == REGCACHE_NONE) {
96 map->cache_bypass = true;
100 for (i = 0; i < ARRAY_SIZE(cache_types); i++)
101 if (cache_types[i]->type == map->cache_type)
104 if (i == ARRAY_SIZE(cache_types)) {
105 dev_err(map->dev, "Could not match compress type: %d\n",
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;
113 map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
114 map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
117 map->cache_ops = cache_types[i];
119 if (!map->cache_ops->read ||
120 !map->cache_ops->write ||
121 !map->cache_ops->name)
124 /* We still need to ensure that the reg_defaults
125 * won't vanish from under us. We'll need to make
128 if (config->reg_defaults) {
129 if (!map->num_reg_defaults)
131 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
132 sizeof(struct reg_default), GFP_KERNEL);
135 map->reg_defaults = tmp_buf;
136 } else if (map->num_reg_defaults_raw) {
137 /* Some devices such as PMICs don't have cache defaults,
138 * we cope with this by reading back the HW registers and
139 * crafting the cache defaults by hand.
141 ret = regcache_hw_init(map);
146 if (!map->max_register)
147 map->max_register = map->num_reg_defaults_raw;
149 if (map->cache_ops->init) {
150 dev_dbg(map->dev, "Initializing %s cache\n",
151 map->cache_ops->name);
152 ret = map->cache_ops->init(map);
159 kfree(map->reg_defaults);
161 kfree(map->reg_defaults_raw);
166 void regcache_exit(struct regmap *map)
168 if (map->cache_type == REGCACHE_NONE)
171 BUG_ON(!map->cache_ops);
173 kfree(map->reg_defaults);
175 kfree(map->reg_defaults_raw);
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);
185 * regcache_read: Fetch the value of a given register from the cache.
187 * @map: map to configure.
188 * @reg: The register index.
189 * @value: The value to be returned.
191 * Return a negative value on failure, 0 on success.
193 int regcache_read(struct regmap *map,
194 unsigned int reg, unsigned int *value)
198 if (map->cache_type == REGCACHE_NONE)
201 BUG_ON(!map->cache_ops);
203 if (!regmap_volatile(map, reg)) {
204 ret = map->cache_ops->read(map, reg, value);
207 trace_regmap_reg_read_cache(map->dev, reg, *value);
216 * regcache_write: Set the value of a given register in the cache.
218 * @map: map to configure.
219 * @reg: The register index.
220 * @value: The new register value.
222 * Return a negative value on failure, 0 on success.
224 int regcache_write(struct regmap *map,
225 unsigned int reg, unsigned int value)
227 if (map->cache_type == REGCACHE_NONE)
230 BUG_ON(!map->cache_ops);
232 if (!regmap_writeable(map, reg))
235 if (!regmap_volatile(map, reg))
236 return map->cache_ops->write(map, reg, value);
242 * regcache_sync: Sync the register cache with the hardware.
244 * @map: map to configure.
246 * Any registers that should not be synced should be marked as
247 * volatile. In general drivers can choose not to use the provided
248 * syncing functionality if they so require.
250 * Return a negative value on failure, 0 on success.
252 int regcache_sync(struct regmap *map)
260 BUG_ON(!map->cache_ops);
262 mutex_lock(&map->lock);
263 /* Remember the initial bypass state */
264 bypass = map->cache_bypass;
265 dev_dbg(map->dev, "Syncing %s cache\n",
266 map->cache_ops->name);
267 name = map->cache_ops->name;
268 trace_regcache_sync(map->dev, name, "start");
269 if (!map->cache_dirty)
271 if (map->cache_ops->sync) {
272 ret = map->cache_ops->sync(map);
274 for (i = 0; i < map->num_reg_defaults; i++) {
275 ret = regcache_read(map, i, &val);
278 map->cache_bypass = 1;
279 ret = _regmap_write(map, i, val);
280 map->cache_bypass = 0;
283 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
284 map->reg_defaults[i].reg,
285 map->reg_defaults[i].def);
290 trace_regcache_sync(map->dev, name, "stop");
291 /* Restore the bypass state */
292 map->cache_bypass = bypass;
293 mutex_unlock(&map->lock);
297 EXPORT_SYMBOL_GPL(regcache_sync);
300 * regcache_cache_only: Put a register map into cache only mode
302 * @map: map to configure
303 * @cache_only: flag if changes should be written to the hardware
305 * When a register map is marked as cache only writes to the register
306 * map API will only update the register cache, they will not cause
307 * any hardware changes. This is useful for allowing portions of
308 * drivers to act as though the device were functioning as normal when
309 * it is disabled for power saving reasons.
311 void regcache_cache_only(struct regmap *map, bool enable)
313 mutex_lock(&map->lock);
314 WARN_ON(map->cache_bypass && enable);
315 map->cache_only = enable;
316 trace_regmap_cache_only(map->dev, enable);
317 mutex_unlock(&map->lock);
319 EXPORT_SYMBOL_GPL(regcache_cache_only);
322 * regcache_mark_dirty: Mark the register cache as dirty
326 * Mark the register cache as dirty, for example due to the device
327 * having been powered down for suspend. If the cache is not marked
328 * as dirty then the cache sync will be suppressed.
330 void regcache_mark_dirty(struct regmap *map)
332 mutex_lock(&map->lock);
333 map->cache_dirty = true;
334 mutex_unlock(&map->lock);
336 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
339 * regcache_cache_bypass: Put a register map into cache bypass mode
341 * @map: map to configure
342 * @cache_bypass: flag if changes should not be written to the hardware
344 * When a register map is marked with the cache bypass option, writes
345 * to the register map API will only update the hardware and not the
346 * the cache directly. This is useful when syncing the cache back to
349 void regcache_cache_bypass(struct regmap *map, bool enable)
351 mutex_lock(&map->lock);
352 WARN_ON(map->cache_only && enable);
353 map->cache_bypass = enable;
354 trace_regmap_cache_bypass(map->dev, enable);
355 mutex_unlock(&map->lock);
357 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
359 bool regcache_set_val(void *base, unsigned int idx,
360 unsigned int val, unsigned int word_size)
365 if (cache[idx] == val)
372 if (cache[idx] == val)
379 if (cache[idx] == val)
390 unsigned int regcache_get_val(const void *base, unsigned int idx,
391 unsigned int word_size)
398 const u8 *cache = base;
402 const u16 *cache = base;
406 const u32 *cache = base;
416 static int regcache_default_cmp(const void *a, const void *b)
418 const struct reg_default *_a = a;
419 const struct reg_default *_b = b;
421 return _a->reg - _b->reg;
424 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
426 struct reg_default key;
427 struct reg_default *r;
432 r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
433 sizeof(struct reg_default), regcache_default_cmp);
436 return r - map->reg_defaults;