nordic,nrf-gpio-forwarder

Vendor: Nordic Semiconductor

Description

This is an abstract device responsible for forwarding pins between cores.

In nRF53 family of SoCs, GPIO pins must be explicitly forwarded by
the application core to the network core if the latter should drive them.
The purpose of this abstract device is to represent all GPIO pins that the
nRF53 application core should forward to the nRF53 network core.

Once the control over selected GPIO pins is forwarded to it, the network
core is responsible for configuring the pins and driving them as needed.

Here is an example of how a nrf-gpio-forwarder can be used with a nRF5340
combined with a nRF21540 Front-End module. Consider the following node
present in DTS file targeted for the nRF5340 network core, which defines
the details of the nRF21540 Front-End module's interface:

nrf_radio_fem: nrf21540 {
  compatible = "nordic,nrf21540-fem";
  tx-en-gpios = <&gpio0 30 GPIO_ACTIVE_HIGH>;
  rx-en-gpios = <&gpio1 11 GPIO_ACTIVE_HIGH>;
  pdn-gpios   = <&gpio1 10 GPIO_ACTIVE_HIGH>;
  mode-gpios  = <&gpio1 12 GPIO_ACTIVE_HIGH>;
};

Since the nRF21540 Front-End module should be controlled by the nRF5340
network core, all the GPIO pins used to control it must be forwarded by
the nRF5340 application core to the network core. Consider the following
nrf-gpio-forwarder node defined in DTS file targeted for the nRF5340
application core:

gpio_fwd: nrf-gpio-forwarder {
  compatible = "nordic,nrf-gpio-forwarder";
  nrf21540-gpio-if {
    gpios = <&gpio0 30 0>, <&gpio1 11 0>, <&gpio1 10 0>, <&gpio1 12 0>;
  };
};

In the above example, the nrf-gpio-forwarder node is configured to forward
control over the following GPIO pins to the network core:

  - P0.30 (matching `tx-en-gpios`)
  - P1.11 (matching `rx-en-gpios`)
  - P1.10 (matching `pdn-gpios`)
  - P1.12 (matching `mode-gpios`)

Please note that the GPIO flags provided for child nodes of the forwarder
are ignored. In order to configure the GPIOs passed to the forwarder, their
GPIO flags must be set in the matching node that these GPIOs are forwarded
to. In the above example, the GPIO flags must be set in the nrf21540 node.
They are set to 0 in the nrf-gpio-forwarder node as they are ignored anyway.

Child nodes for the forwarder can be defined independently by multiple DTS
files. They are merged into a single node with multiple child nodes when
processing devicetree for an application build. However, in order for that
to happen, names of the child nodes must be unique in the scope of a single
nrf-gpio-forwarder instance.

Properties

Top level properties

These property descriptions apply to “nordic,nrf-gpio-forwarder” nodes themselves. This page also describes child node properties in the following sections.

Node specific properties

Properties not inherited from the base binding file.

(None)

Deprecated node specific properties

Deprecated properties not inherited from the base binding file.

(None)

Base properties

Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “nordic,nrf-gpio-forwarder” compatible.

Name

Type

Details

status

string

 
Indicates the operational status of the hardware or other
resource that the node represents. In particular:

  - "okay" means the resource is operational and, for example,
    can be used by device drivers
  - "disabled" means the resource is not operational and the system
    should treat it as if it is not present

For details, see "2.3.4 status" in Devicetree Specification v0.4.

Legal values: 'ok', 'okay', 'disabled', 'reserved', 'fail', 'fail-sss'

See Important properties for more information.

compatible

string-array

 
This property is a list of strings that essentially define what
type of hardware or other resource this devicetree node
represents. Each device driver checks for specific compatible
property values to find the devicetree nodes that represent
resources that the driver should manage.

The recommended format is "vendor,device", The "vendor" part is
an abbreviated name of the vendor. The "device" is usually from
the datasheet.

The compatible property can have multiple values, ordered from
most- to least-specific. Having additional values is useful when the
device is a specific instance of a more general family, to allow the
system to match the most specific driver available.

For details, see "2.3.1 compatible" in Devicetree Specification v0.4.

This property is required.

See Important properties for more information.

reg

array

 
Information used to address the device. The value is specific to
the device (i.e. is different depending on the compatible
property).

The "reg" property is typically a sequence of (address, length) pairs.
Each pair is called a "register block". Values are
conventionally written in hex.

For details, see "2.3.6 reg" in Devicetree Specification v0.4.

See Important properties for more information.

reg-names

string-array

 
Optional names given to each register block in the "reg" property.
For example:

  / {
       soc {
           #address-cells = <1>;
           #size-cells = <1>;

           uart@1000 {
               reg = <0x1000 0x2000>, <0x3000 0x4000>;
               reg-names = "foo", "bar";
           };
       };
  };

The uart@1000 node has two register blocks:

  - one with base address 0x1000, size 0x2000, and name "foo"
  - another with base address 0x3000, size 0x4000, and name "bar"

interrupts

array

 
Information about interrupts generated by the device, encoded as an array
of one or more interrupt specifiers. The format of the data in this property
varies by where the device appears in the interrupt tree. Devices with the same
"interrupt-parent" will use the same format in their interrupts properties.

For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.

See Important properties for more information.

interrupts-extended

compound

 
Extended interrupt specifier for device, used as an alternative to
the "interrupts" property.

For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.

interrupt-names

string-array

 
Optional names given to each interrupt generated by a device.
The interrupts themselves are defined in either "interrupts" or
"interrupts-extended" properties.

For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.

interrupt-parent

phandle

 
If present, this refers to the node which handles interrupts generated
by this device.

For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.

label

string

 
Human readable string describing the device. Use of this property is
deprecated except as needed on a case-by-case basis.

For details, see "4.1.2 Miscellaneous Properties" in Devicetree
Specification v0.4.

See Important properties for more information.

clocks

phandle-array

 
Information about the device's clock providers. In general, this property
should follow conventions established in the dt-schema binding:

  https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/clock/clock.yaml

clock-names

string-array

 
Optional names given to each clock provider in the "clocks" property.

#address-cells

int

 
This property encodes the number of <u32> cells used by address fields
in "reg" properties in this node's children.

For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.

#size-cells

int

 
This property encodes the number of <u32> cells used by size fields in
"reg" properties in this node's children.

For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.

dmas

phandle-array

 
DMA channel specifiers relevant to the device.

dma-names

string-array

 
Optional names given to the DMA channel specifiers in the "dmas" property.

io-channels

phandle-array

 
IO channel specifiers relevant to the device.

io-channel-names

string-array

 
Optional names given to the IO channel specifiers in the "io-channels" property.

mboxes

phandle-array

 
Mailbox / IPM channel specifiers relevant to the device.

mbox-names

string-array

 
Optional names given to the mbox specifiers in the "mboxes" property.

power-domains

phandle-array

 
Power domain specifiers relevant to the device.

power-domain-names

string-array

 
Optional names given to the power domain specifiers in the "power-domains" property.

#power-domain-cells

int

 
Number of cells in power-domains property

zephyr,deferred-init

boolean

 
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().

wakeup-source

boolean

 
Property to identify that a device can be used as wake up source.

When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.

Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.

zephyr,pm-device-runtime-auto

boolean

 
Automatically configure the device for runtime power management after the
init function runs.

zephyr,disabling-power-states

phandles

 
List of power states that will disable this device power.

Child node properties

Name

Type

Details

gpios

phandle-array

 
Array of GPIOs to be forwarded. Note that GPIO flags provided for
elements of this array are ignored. In order to configure the GPIOs
from this array, their GPIO flags must be set in the matching
node that these GPIOs are forwarded to.

This property is required.