Some device drivers cannot use instance numbers. Option 2: create devices using node labels ¶ Semicolon or function definition to support multiple devices. It does not append a semicolon to the end of theĮxpansion of CREATE_MY_DEVICE, so the macro’s expansion must end in a * Call the device creation macro for each instance: */ DT_INST_FOREACH_STATUS_OKAY ( CREATE_MY_DEVICE )ĭT_INST_FOREACH_STATUS_OKAY expands to code which callsĬREATE_MY_DEVICE once for each enabled node with the compatible determinedīy DT_DRV_COMPAT. For example, if your driver’s compatible is "vnd,my-device" inĭevicetree, you would define DT_DRV_COMPAT to vnd_my_device in your Lowercase-and-underscores version of the compatible that the device driver To use instance-based APIs, begin by defining DT_DRV_COMPAT to the They only work when devicetree nodes for your driver’s compatible are allĮquivalent, and you do not need to be able to distinguish between them. Use this option, which uses Instance-based APIs, if possible. * my_driver.c */ #include /* Define data (RAM) and configuration (ROM) structures: */ struct my_dev_data Option 1: create devices using instance numbers ¶ They assume you’ve already implemented theĭevice-specific configuration and data structures and API functions, like this: This allows users to configure the driverĮxamples for how to do this follow. This allows the driver’s users to Get a struct device from a devicetree node inĮach device’s initial configuration should use values from devicetree Struct device: using instance numbers, and using node labels.Įach struct device‘s name should be set to its devicetree node’s There are two options for instantiating each To find status = "okay" nodes with the desired compatible, and instantiateĪ struct device for each one. See Find a devicetree binding for more advice on locating existing bindings.Īfter writing your binding, your driver C file can then use the devicetree API A skeletal binding to get startedĭescription : compatible : "foo-company,bar-device" include : base.yaml Use existing bindingsįrom similar drivers as a starting point. Writing a devicetree-aware driver begins by defining a devicetree binding for the devices supported by the driver. Struct device for each status = "okay" devicetree node with a “Devicetree-aware” device drivers should create a Write device drivers using devicetree APIs ¶ My_spi_device and my_i2c_device compatibles, you should now be able toĮnable the driver via Kconfig and get the struct deviceįor your newly added bus node, then use it with that driver API. Set its properties according to its bindingĪssuming you have a suitable device driver associated with the ![]() Other bus devices can be configured similarly:Ĭreate the device as a subnode of the parent bus * Configure other I2C device properties as needed. * Find your device's DT binding for details. * Configure other SPI device properties as needed. * If present, it must match the node's unit address. * reg is the chip select number, if needed ![]() The build system prints all the devicetree overlays itįinds in the configuration phase, like this: The DTC_OVERLAY_FILE value is stored in the CMake cache and used Using Shields will also add devicetree overlay files. Otherwise, if app.overlay exists, it will be used. overlay exists, it will be used, and the build If one or more files have been found in the previous steps, the build system This file will be used in addition to boards/.overlay If the current board has multiple revisionsĪnd boards/_.overlay exists, it will be used. If the file boards/.overlay exists, it will be used. These steps, looking for files in your application source directory to use If you don’t set DTC_OVERLAY_FILE, the build system will follow You can set DTC_OVERLAY_FILE to contain exactly the files you want If DTC_OVERLAY_FILE specifies multipleįiles, they are included in that order by the C preprocessor. Variable DTC_OVERLAY_FILE contains a space- or semicolon-separated Set devicetree overlays ¶ĭevicetree overlays are explained in Introduction to devicetree. See Check for missing bindings for troubleshooting. ![]() * * Devicetree node: * * * Binding (compatible = soc-nv-flash): * $ZEPHYR_BASE/dts/bindings/mtd/soc-nv-flash.yaml * */
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