The regmap API is quite simple. There are only a few structures to know. The two most important structures of this API are struct regmap_config, which represents the configuration of the regmap, and struct regmap, which is the regmap instance itself. All of the regmap data structures are defined in include/linux/regmap.h.
Programming with the regmap API
regmap_config structure
struct regmap_config stores the configuration of the regmap during the driver's lifetime. What you set here affects read/write operations. It is the most important structure in the regmap API. The source looks like this:
struct regmap_config { const char *name; int reg_bits; int reg_stride; int pad_bits; int val_bits;...