regmap: reg_default_cb for flat cache defaults

Merge series from "Sheetal ." <sheetal@nvidia.com>:

This series adds a reg_default_cb callback for REGCACHE_FLAT to provide
defaults for registers not listed in reg_defaults. Defaults are loaded
eagerly during regcache init and the callback can use writeable_reg to
filter valid addresses and avoid holes.

Tegra ASoC drivers set reg_default_cb and add writeable_reg filtering for
AHUB RX holes to prevent invalid addresses from being marked valid.

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b0b9be750d93..caff2240bdab 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -359,6 +359,10 @@ typedef void (*regmap_unlock)(void *);
  * @reg_defaults: Power on reset values for registers (for use with
  *                register cache support).
  * @num_reg_defaults: Number of elements in reg_defaults.
+ * @reg_default_cb: Optional callback to return default values for registers
+ *                  not listed in reg_defaults. This is only used for
+ *                  REGCACHE_FLAT population; drivers must ensure the readable_reg/
+ *                  writeable_reg callbacks are defined to handle holes.
  *
  * @read_flag_mask: Mask to be set in the top bytes of the register when doing
  *                  a read.
@@ -449,6 +453,8 @@ struct regmap_config {
 	const struct regmap_access_table *rd_noinc_table;
 	const struct reg_default *reg_defaults;
 	unsigned int num_reg_defaults;
+	int (*reg_default_cb)(struct device *dev, unsigned int reg,
+			      unsigned int *def);
 	enum regcache_type cache_type;
 	const void *reg_defaults_raw;
 	unsigned int num_reg_defaults_raw;
@@ -1349,6 +1355,14 @@ static inline int regmap_write_bits(struct regmap *map, unsigned int reg,
 	return regmap_update_bits_base(map, reg, mask, val, NULL, false, true);
 }
 
+static inline int regmap_default_zero_cb(struct device *dev,
+					 unsigned int reg,
+					 unsigned int *def)
+{
+	*def = 0;
+	return 0;
+}
+
 int regmap_get_val_bytes(struct regmap *map);
 int regmap_get_max_register(struct regmap *map);
 int regmap_get_reg_stride(struct regmap *map);