regmap: Introduce regmap_get_max_register

This patch introduces regmap_get_max_register() function which would be
used by the infrastructures like nvmem framework built on top of
regmap.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap.c

@@ -2613,6 +2613,18 @@ int regmap_get_val_bytes(struct regmap *map)
 }
 EXPORT_SYMBOL_GPL(regmap_get_val_bytes);
 
+/**
+ * regmap_get_max_register(): Report the max register value
+ *
+ * Report the max register value, mainly intended to for use by
+ * generic infrastructure built on top of regmap.
+ */
+int regmap_get_max_register(struct regmap *map)
+{
+	return map->max_register ? map->max_register : -EINVAL;
+}
+EXPORT_SYMBOL_GPL(regmap_get_max_register);
+
 int regmap_parse_val(struct regmap *map, const void *buf,
 			unsigned int *val)
 {

include/linux/regmap.h

@@ -433,6 +433,7 @@ int regmap_update_bits_check_async(struct regmap *map, unsigned int reg,
 				   unsigned int mask, unsigned int val,
 				   bool *change);
 int regmap_get_val_bytes(struct regmap *map);
+int regmap_get_max_register(struct regmap *map);
 int regmap_async_complete(struct regmap *map);
 bool regmap_can_raw_write(struct regmap *map);
 
@@ -676,6 +677,12 @@ static inline int regmap_get_val_bytes(struct regmap *map)
 	return -EINVAL;
 }
 
+static inline int regmap_get_max_register(struct regmap *map)
+{
+	WARN_ONCE(1, "regmap API is disabled");
+	return -EINVAL;
+}
+
 static inline int regcache_sync(struct regmap *map)
 {
 	WARN_ONCE(1, "regmap API is disabled");