# Copyright (c) 2018, I-SENSE group of ICCS # SPDX-License-Identifier: Apache-2.0 # Common fields for SPI controllers include: base.yaml bus: spi properties: clock-frequency: type: int description: | Clock frequency the SPI peripheral is being driven at, in Hz. "#address-cells": required: true const: 1 "#size-cells": required: true const: 0 cs-gpios: type: phandle-array description: | An array of chip select GPIOs to use. Each element in the array specifies a GPIO. The index in the array corresponds to the child node that the CS gpio controls. Example: spi@... { cs-gpios = <&gpio0 23 GPIO_ACTIVE_LOW>, <&gpio1 10 GPIO_ACTIVE_LOW>, ...; spi-device@0 { reg = <0>; ... }; spi-device@1 { reg = <1>; ... }; ... }; The child node "spi-device@0" specifies a SPI device with chip select controller gpio0, pin 23, and devicetree GPIO flags GPIO_ACTIVE_LOW. Similarly, "spi-device@1" has CS GPIO controller gpio1, pin 10, and flags GPIO_ACTIVE_LOW. Additional devices can be configured in the same way. If unsure about the flags cell, GPIO_ACTIVE_LOW is generally a safe choice for a typical "CSn" pin. GPIO_ACTIVE_HIGH may be used if intervening hardware inverts the signal to the peripheral device or the line itself is active high. If this property is not defined, no chip select GPIOs are set. SPI controllers with dedicated CS pins do not need to define the cs-gpios property. overrun-character: type: int description: | The overrun character (ORC) is used when all bytes from the TX buffer are sent, but the transfer continues due to RX.