registerval

Registerval, often written regval, is a term used in low-level hardware programming to denote the data written to a hardware register as part of a configuration or initialization sequence. It commonly appears in driver code, firmware boot sequences, and interfaces for configuring devices such as sensors, regulators, and controllers.

Representations vary by platform. In many driver implementations, a regval is a small structure with fields for a register address and a value to write. In other contexts, a regval is a 32-bit word where the high bits encode the register address and the low bits encode the value, or a pair of 16-bit fields separated by a mask. The exact layout depends on the bus protocol (I2C, SPI, MMIO) and the device's register map.

Usage often involves defining a sequence of regval entries that initialize the device, then applying the sequence at startup or during reconfiguration. Helpers may perform the writes in order and may support termination markers or counting the number of entries to process.

Examples of contexts: In Linux kernel development, regval-like sequences are used for device initialization through regmap or direct MMIO access, within drivers for sensors, power regulators, and other peripherals. In other ecosystems, similar concepts appear under names such as register write sequences or write-register tables.

See also: regmap, register map, I2C, SPI, device driver initialization. Note that registerval is not a universal standardized type; its exact form is platform- and API-specific.