Buses - Qualcomm Dragonwing Documentation

A bus facilitates data transfer among various system components. You can use the DT properties to configure the Qualcomm Universal Peripheral (QUP) v3 serial interface device nodes. QUP v3 supports interintegrated circuit (I²C), serial peripheral interface (SPI), and universal asynchronous receiver-transmitter (UART) serial engines. The DT properties include the active and sleep settings for these serial engines. For more information about QUP v3 and its peripheral interfaces, see Overview of peripheral interfaces. You can apply the serial engine protocol and active configurations when the firmware loads onto the serial engine. You can configure the following Linux host files:

boot_images/boot/Settings/Soc/<chipset>/Core/Buses/qup_common/<chipset>-qupv3-pinctrl.dtsi
boot_images/boot/Settings/Soc/<chipset>/Core/Buses/qup_common/<chipset>-qupv3.dtsi

In &top_qup{k}_se{n}, k represents the QUP number and n represents the serial engine number. The table lists the DT properties:

Table: Bus DT properties

Property name	Property description	Data type	Possible values/value range	Device behavior
`status = "disabled";`	Status control to enable/disable serial interfaces supported for QUP v3 serial engine (I²C/SPI/UART) protocols.	String	Okay Disabled	Enables or disables the serial engine.
`&top_qup{k}_se{n}_i2c_active`	GPIOs active settings for I²C serial engines.	UINT32-array	Reference to a node label.	Sets active GPIO configurations for the I²C protocol.
`&top_qup{k}_se{n}_i2c_sleep`	GPIOs sleep settings for I²C.	UINT32-array	Reference to a node label.	Sets sleep GPIO configurations for the I²C protocol.
`&top_qup{k}_se{n}_spi_active`	GPIOs active settings for SPI.	UINT32-array	Reference to a node label.	Sets active GPIO configurations for the SPI protocol.
`&top_qup{k}_se{n}_spi_sleep`	GPIOs sleep settings for SPI.	UINT32-array	Reference to a node label.	Sets sleep GPIO configurations for the SPI protocol.
`&top_qup{k}_se{n}_uart_active`	GPIOs active settings for UART.	UINT32-array	Reference to a node label.	Sets active GPIO configurations for the UART protocol.
`&top_qup{k}_se{n}_uart_sleep`	GPIOs sleep settings for UART.	UINT32-array	Reference to a node label.	Sets sleep GPIO configurations for the UART protocol.

Sample configuration

TOP_QUP_0{}
/*TOP_QUP_0_SE_0 Instance */
TOP_QUP_0_SE_0
status = "disabled"; /* status to enable/disable SE0 Node */
pinctrl-0  = <&top_qup0_se0_i2c_active>;
pinctrl-1  = <&top_qup0_se0_i2c_sleep>;
pinctrl-2  = <&top_qup0_se0_spi_active>;
pinctrl-3  = <&top_qup0_se0_spi_sleep>;
pinctrl-4  = <&top_qup0_se0_uart_active>;
pinctrl-5  = <&top_qup0_se0_uart_sleep>;

​Sample configuration

Sample configuration