From 4d4cfd1656b5f6c88eae51c40741a695b108b006 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 23 Feb 2012 20:53:37 +0000 Subject: 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 --- drivers/base/regmap/regcache.c | 45 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'drivers/base') diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c index aec5a74..b35f875 100644 --- a/drivers/base/regmap/regcache.c +++ b/drivers/base/regmap/regcache.c @@ -299,6 +299,51 @@ out: 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 -- cgit v1.1