regmap: Allow drivers to sync only part of the register cache

Provide a regcache_sync_region() operation which allows drivers to write only part of the cache back to the hardware. This is intended for use in cases like power domains or DSP memories where part of the device register map may be reset without fully resetting the device. Fully supporting these devices is likely to require additional work to make specific regions of the register map cache only while they are in reset, but this is enough for most devices. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Allow drivers to sync only part of the register cache
Provide a regcache_sync_region() operation which allows drivers to write only part of the cache back to the hardware. This is intended for use in cases like power domains or DSP memories where part of the device register map may be reset without fully resetting the device. Fully supporting these devices is likely to require additional work to make specific regions of the register map cache only while they are in reset, but this is enough for most devices. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Mark Brown
1 parent ac8d91c801
Showing 2 changed files with 47 additions and 0 deletions Side-by-side Diff
drivers/base/regmap/regcache.c
include/linux/regmap.h
@@ -299,6 +299,51 @@
 EXPORT_SYMBOL_GPL(regcache_sync);
  
 /**
+ * regcache_sync_region: Sync part  of the register cache with the hardware.
+ *
+ * @map: map to sync.
+ * @min: first register to sync
+ * @max: last register to sync
+ *
+ * Write all non-default register values in the specified region to
+ * the hardware.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_sync_region(struct regmap *map, unsigned int min,
+			 unsigned int max)
+{
+	int ret = 0;
+	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;
+
+	name = map->cache_ops->name;
+	dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
+
+	trace_regcache_sync(map->dev, name, "start region");
+
+	if (!map->cache_dirty)
+		goto out;
+
+	ret = map->cache_ops->sync(map, min, max);
+
+out:
+	trace_regcache_sync(map->dev, name, "stop region");
+	/* Restore the bypass state */
+	map->cache_bypass = bypass;
+	mutex_unlock(&map->lock);
+
+	return ret;
+}
+
+/**
  * regcache_cache_only: Put a register map into cache only mode
  *
  * @map: map to configure
@@ -145,6 +145,8 @@
 			     bool *change);
  
 int regcache_sync(struct regmap *map);
+int regcache_sync_region(struct regmap *map, unsigned int min,
+			 unsigned int max);
 void regcache_cache_only(struct regmap *map, bool enable);
 void regcache_cache_bypass(struct regmap *map, bool enable);
 void regcache_mark_dirty(struct regmap *map);
...	...	@@ -299,6 +299,51 @@
299	299	EXPORT_SYMBOL_GPL(regcache_sync);
300	300
301	301	/**
	302	+ * regcache_sync_region: Sync part of the register cache with the hardware.
	303	+ *
	304	+ * @map: map to sync.
	305	+ * @min: first register to sync
	306	+ * @max: last register to sync
	307	+ *
	308	+ * Write all non-default register values in the specified region to
	309	+ * the hardware.
	310	+ *
	311	+ * Return a negative value on failure, 0 on success.
	312	+ */
	313	+int regcache_sync_region(struct regmap *map, unsigned int min,
	314	+ unsigned int max)
	315	+{
	316	+ int ret = 0;
	317	+ const char *name;
	318	+ unsigned int bypass;
	319	+
	320	+ BUG_ON(!map->cache_ops \|\| !map->cache_ops->sync);
	321	+
	322	+ mutex_lock(&map->lock);
	323	+
	324	+ /* Remember the initial bypass state */
	325	+ bypass = map->cache_bypass;
	326	+
	327	+ name = map->cache_ops->name;
	328	+ dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
	329	+
	330	+ trace_regcache_sync(map->dev, name, "start region");
	331	+
	332	+ if (!map->cache_dirty)
	333	+ goto out;
	334	+
	335	+ ret = map->cache_ops->sync(map, min, max);
	336	+
	337	+out:
	338	+ trace_regcache_sync(map->dev, name, "stop region");
	339	+ /* Restore the bypass state */
	340	+ map->cache_bypass = bypass;
	341	+ mutex_unlock(&map->lock);
	342	+
	343	+ return ret;
	344	+}
	345	+
	346	+/**
302	347	* regcache_cache_only: Put a register map into cache only mode
303	348	*
304	349	* @map: map to configure
...	...	@@ -145,6 +145,8 @@
145	145	bool *change);
146	146
147	147	int regcache_sync(struct regmap *map);
	148	+int regcache_sync_region(struct regmap *map, unsigned int min,
	149	+ unsigned int max);
148	150	void regcache_cache_only(struct regmap *map, bool enable);
149	151	void regcache_cache_bypass(struct regmap *map, bool enable);
150	152	void regcache_mark_dirty(struct regmap *map);