|.. SPDX-License-Identifier: GPL-2.0
|DOs and DON'Ts for designing and writing Devicetree bindings
|This is a list of common review feedback items focused on binding design. With
|every rule, there are exceptions and bindings have many gray areas.
|For guidelines related to patches, see
|- DO attempt to make bindings complete even if a driver doesn't support some
| features. For example, if a device has an interrupt, then include the
| 'interrupts' property even if the driver is only polled mode.
|- DON'T refer to Linux or "device driver" in bindings. Bindings should be
| based on what the hardware has, not what an OS and driver currently support.
|- DO use node names matching the class of the device. Many standard names are
| defined in the DT Spec. If there isn't one, consider adding it.
|- DO check that the example matches the documentation especially after making
| review changes.
|- DON'T create nodes just for the sake of instantiating drivers. Multi-function
| devices only need child nodes when the child nodes have their own DT
| resources. A single node can be multiple providers (e.g. clocks and resets).
|- DON'T use 'syscon' alone without a specific compatible string. A 'syscon'
| hardware block should have a compatible string unique enough to infer the
| register layout of the entire block (at a minimum).
|- DO make 'compatible' properties specific. DON'T use wildcards in compatible
| strings. DO use fallback compatibles when devices are the same as or a subset
| of prior implementations. DO add new compatibles in case there are new
| features or bugs.
|- DO use a vendor prefix on device-specific property names. Consider if
| properties could be common among devices of the same class. Check other
| existing bindings for similar devices.
|- DON'T redefine common properties. Just reference the definition and define
| constraints specific to the device.
|- DO use common property unit suffixes for properties with scientific units.
| Recommended suffixes are listed at
|- DO define properties in terms of constraints. How many entries? What are
| possible values? What is the order?
|Board/SoC .dts Files
|- DO put all MMIO devices under a bus node and not at the top-level.
|- DO use non-empty 'ranges' to limit the size of child buses/devices. 64-bit
| platforms don't need all devices to have 64-bit address and size.