doc/guides/dts/macros.bnf

; An RFC 7405 ABNF grammar for devicetree macros.
;
; This does *not* cover macros pulled out of DT via Kconfig,
; like CONFIG_SRAM_BASE_ADDRESS, etc. It only describes the
; ones that start with DT_ and are directly generated, not
; defined in a dts_fixup.h file.

; --------------------------------------------------------------------
; dt-macro: the top level nonterminal for a devicetree macro
;
; A dt-macro starts with uppercase "DT_", and is one of:
;
; - a <node-macro>, generated for a particular node
; - some <other-macro>, a catch-all for other types of macros
dt-macro = node-macro / other-macro

; --------------------------------------------------------------------
; node-macro: a macro related to a node

; A macro about a property value
node-macro =  property-macro
; EXISTS macro: node exists in the devicetree
node-macro =/ %s"DT_N" path-id %s"_EXISTS"
; Bus macros: the plain BUS is a way to access a node's bus controller.
; The additional dt-name suffix is added to match that node's bus type;
; the dt-name in this case is something like "spi" or "i2c".
node-macro =/ %s"DT_N" path-id %s"_BUS" ["_" dt-name]
; The reg property is special and has its own macros.
node-macro =/ %s"DT_N" path-id %s"_REG_NUM"
node-macro =/ %s"DT_N" path-id %s"_REG_IDX_" DIGIT "_EXISTS"
node-macro =/ %s"DT_N" path-id %s"_REG_IDX_" DIGIT
              %s"_VAL_" ( %s"ADDRESS" / %s"SIZE")
node-macro =/ %s"DT_N" path-id %s"_REG_NAME_" dt-name
              %s"_VAL_" ( %s"ADDRESS" / %s"SIZE")
; The interrupts property is also special.
node-macro =/ %s"DT_N" path-id %s"_IRQ_NUM"
node-macro =/ %s"DT_N" path-id %s"_IRQ_IDX_" DIGIT "_EXISTS"
node-macro =/ %s"DT_N" path-id %s"_IRQ_IDX_" DIGIT
              %s"_VAL_" dt-name [ %s"_EXISTS" ]
node-macro =/ %s"DT_N" path-id %s"_IRQ_NAME_" dt-name
              %s"_VAL_" dt-name [ %s"_EXISTS" ]
; Subnodes of the fixed-partitions compatible get macros which contain
; a unique ordinal value for each partition
node-macro =/ %s"DT_N" path-id %s"_PARTITION_ID" DIGIT
; Macros are generated for each of a node's compatibles;
; dt-name in this case is something like "vnd_device".
node-macro =/ %s"DT_N" path-id %s"_COMPAT_MATCHES_" dt-name
; Every non-root node gets one of these macros, which expands to the node
; identifier for that node's parent in the devicetree.
node-macro =/ %s"DT_N" path-id %s"_PARENT"
; These are used internally by DT_FOREACH_CHILD, which iterates over
; each child node.
node-macro =/ %s"DT_N" path-id %s"_FOREACH_CHILD"
; These are used internally by DT_FOREACH_CHILD_STATUS_OKAY, which iterates
; over each child node with status "okay".
node-macro =/ %s"DT_N" path-id %s"_FOREACH_CHILD_STATUS_OKAY"
; The node's status macro; dt-name in this case is something like "okay"
; or "disabled".
node-macro =/ %s"DT_N" path-id %s"_STATUS_" dt-name
; The node's dependency ordinal. This is a non-negative integer
; value that is used to represent dependency information.
node-macro =/ %s"DT_N" path-id %s"_ORD"
; The node's path, as a string literal
node-macro =/ %s"DT_N" path-id %s"_PATH"
; The node's name@unit-addr, as a string literal
node-macro =/ %s"DT_N" path-id %s"_FULL_NAME"
; The dependency ordinals of a node's requirements (direct dependencies).
node-macro =/ %s"DT_N" path-id %s"_REQUIRES_ORDS"
; The dependency ordinals of a node supports (reverse direct dependencies).
node-macro =/ %s"DT_N" path-id %s"_SUPPORTS_ORDS"

; --------------------------------------------------------------------
; property-macro: a macro related to a node property
;
; These combine a node identifier with a "lowercase-and-underscores form"
; property name. The value expands to something related to the property's
; value.
;
; The optional prop-suf suffix is when there's some specialized
; subvalue that deserves its own macro, like the macros for an array
; property's individual elements
;
; The "plain vanilla" macro for a property's value, with no prop-suf,
; looks like this:
;
;   DT_N_<node path>_P_<property name>
;
; Components:
;
; - path-id: node's devicetree path converted to a C token
; - prop-id: node's property name converted to a C token
; - prop-suf: an optional property-specific suffix
property-macro =  %s"DT_N" path-id %s"_P_" prop-id [prop-suf]

; --------------------------------------------------------------------
; path-id: a node's path-based macro identifier
;
; This in "lowercase-and-underscores" form. I.e. it is
; the node's devicetree path converted to a C token by changing:
;
; - each slash (/) to _S_
; - all letters to lowercase
; - non-alphanumerics characters to underscores
;
; For example, the leaf node "bar-BAZ" in this devicetree:
;
;   / {
;           foo@123 {
;                   bar-BAZ {};
;           };
;   };
;
; has path-id "_S_foo_123_S_bar_baz".
path-id = 1*( %s"_S_" dt-name )

; ----------------------------------------------------------------------
; prop-id: a property identifier
;
; A property name converted to a C token by changing:
;
; - all letters to lowercase
; - non-alphanumeric characters to underscores
;
; Example node:
;
;   chosen {
;       zephyr,console = &uart1;
;       WHY,AM_I_SHOUTING = "unclear";
;   };
;
; The 'zephyr,console' property has prop-id 'zephyr_console'.
; 'WHY,AM_I_SHOUTING' has prop-id 'why_am_i_shouting'.
prop-id = dt-name

; ----------------------------------------------------------------------
; prop-suf: a property-specific macro suffix
;
; Extra macros are generated for properties:
;
; - that are special to the specification ("reg", "interrupts", etc.)
; - with array types (uint8-array, phandle-array, etc.)
; - with "enum:" in their bindings
; - that have zephyr device API specific macros for phandle-arrays
; - related to phandle specifier names ("foo-names")
;
; Here are some examples:
;
; - _EXISTS: property, index or name existence flag
; - _SIZE: logical property length
; - _IDX_<i>: values of individual array elements
; - _IDX_<DIGIT>_VAL_<dt-name>: values of individual specifier
;   cells within a phandle array
; - _ADDR_<i>: for reg properties, the i-th register block address
; - _LEN_<i>: for reg properties, the i-th register block length
;
; The different cases are not exhaustively documented here to avoid
; this file going stale. Please see devicetree.h if you need to know
; the details.
prop-suf = 1*( "_" gen-name ["_" dt-name] )

; --------------------------------------------------------------------
; other-macro: grab bag for everything that isn't a node-macro.

; See examples below.
other-macro =  %s"DT_N_" alternate-id
; Total count of enabled instances of a compatible.
other-macro =/ %s"DT_N_INST_" dt-name %s"_NUM_OKAY"
; These are used internally by DT_INST_FOREACH, which iterates over
; each enabled instance of a compatible.
other-macro =/ %s"DT_FOREACH_OKAY_INST_" dt-name
; E.g.: #define DT_CHOSEN_zephyr_flash
other-macro =/ %s"DT_CHOSEN_" dt-name
; Declares that a compatible has at least one node on a bus.
; Example:
;
;   #define DT_COMPAT_vnd_dev_BUS_spi 1
other-macro =/ %s"DT_COMPAT_" dt-name %s"_BUS_" dt-name
; Declares that a compatible has at least one status "okay" node.
; Example:
;
;   #define DT_COMPAT_HAS_OKAY_vnd_dev 1
other-macro =/ %s"DT_COMPAT_HAS_OKAY_" dt-name
; Currently used to allow mapping a lowercase-and-underscores "label"
; property to a fixed-partitions node. See the flash map API docs
; for an example.
other-macro =/ %s"DT_COMPAT_" dt-name %s"_LABEL_" dt-name

; --------------------------------------------------------------------
; alternate-id: another way to specify a node besides a path-id
;
; Example devicetree:
;
;   / {
;           aliases {
;                   dev = &dev_1;
;           };
;
;           soc {
;               dev_1: device@123 {
;                   compatible = "vnd,device";
;               };
;           };
;   };
;
; Node device@123 has these alternate-id values:
;
; - ALIAS_dev
; - NODELABEL_dev_1
; - INST_0_vnd_device
;
; The full alternate-id macros are:
;
;   #define DT_N_INST_0_vnd_device     DT_N_S_soc_S_device_123
;   #define DT_N_ALIAS_dev             DT_N_S_soc_S_device_123
;   #define DT_N_NODELABEL_dev_1       DT_N_S_soc_S_device_123
;
; These mainly exist to allow pasting an alternate-id macro onto a
; "_P_<prop-id>" to access node properties given a node's alias, etc.
;
; Notice that "inst"-type IDs have a leading instance identifier,
; which is generated by the devicetree scripts. The other types of
; alternate-id begin immediately with names taken from the devicetree.
alternate-id =  ( %s"ALIAS" / %s"NODELABEL" ) dt-name
alternate-id =/ %s"INST_" 1*DIGIT "_" dt-name

; --------------------------------------------------------------------
; miscellaneous helper definitions

; A dt-name is one or more:
; - lowercase ASCII letters (a-z)
; - numbers (0-9)
; - underscores ("_")
;
; They are the result of converting names or combinations of names
; from devicetree to a valid component of a C identifier by
; lowercasing letters (in practice, this is a no-op) and converting
; non-alphanumeric characters to underscores.
;
; You'll see these referred to as "lowercase-and-underscores" forms of
; various devicetree identifiers throughout the documentation.
dt-name = 1*( lower / DIGIT / "_" )

; gen-name is used as a stand-in for a component of a generated macro
; name which does not come from devicetree (dt-name covers that case).
;
; - uppercase ASCII letters (a-z)
; - numbers (0-9)
; - underscores ("_")
gen-name = upper 1*( upper / DIGIT / "_" )

; "lowercase ASCII letter" turns out to be pretty annoying to specify
; in RFC-7405 syntax.
;
; This is just ASCII letters a (0x61) through z (0x7a).
lower = %x61-7A

; "uppercase ASCII letter" in RFC-7405 syntax
upper = %x41-5A