Linux Device Drivers Development

regmap initialization

As we said earlier, the regmap API supports both SPI and I2C protocols. Depending on the protocol you need to support in your driver, you will have to call either regmap_init_i2c() or regmap_init_spi() in the probe function. To write a generic driver, regmap is the best choice.

The regmap API is generic and homogenous. Only the initialization changes between bus types. Other functions are the same.

It is a good practice always to initialize the regmap in the probe function, and you must always fill the regmap_config elements prior to initializing the regmap.

Whether you allocated an I2C or SPI register map, it is freed with the regmap_exit function:

void regmap_exit(struct regmap *map) 

This function simply releases ...