regmap: Add support for discarding parts of the register cache
Allow drivers to discard parts of the register cache, for example if part
of the hardware has been reset.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index c130536..b33a4ff 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -148,6 +148,7 @@
int (*read)(struct regmap *map, unsigned int reg, unsigned int *value);
int (*write)(struct regmap *map, unsigned int reg, unsigned int value);
int (*sync)(struct regmap *map, unsigned int min, unsigned int max);
+ int (*drop)(struct regmap *map, unsigned int min, unsigned int max);
};
bool regmap_writeable(struct regmap *map, unsigned int reg);
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 75923f2..8a0ab5f 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -359,6 +359,43 @@
EXPORT_SYMBOL_GPL(regcache_sync_region);
/**
+ * regcache_drop_region: Discard part of the register cache
+ *
+ * @map: map to operate on
+ * @min: first register to discard
+ * @max: last register to discard
+ *
+ * Discard part of the register cache.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_drop_region(struct regmap *map, unsigned int min,
+ unsigned int max)
+{
+ unsigned int reg;
+ int ret = 0;
+
+ if (!map->cache_present && !(map->cache_ops && map->cache_ops->drop))
+ return -EINVAL;
+
+ map->lock(map);
+
+ trace_regcache_drop_region(map->dev, min, max);
+
+ if (map->cache_present)
+ for (reg = min; reg < max + 1; reg++)
+ clear_bit(reg, map->cache_present);
+
+ if (map->cache_ops && map->cache_ops->drop)
+ ret = map->cache_ops->drop(map, min, max);
+
+ map->unlock(map);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(regcache_drop_region);
+
+/**
* regcache_cache_only: Put a register map into cache only mode
*
* @map: map to configure
