:orphan:
.. raw:: html
.. dtcompatible:: nordic,nrf21540-fem
.. _dtbinding_nordic_nrf21540_fem:
nordic,nrf21540-fem
###################
Vendor: :ref:`Nordic Semiconductor `
Description
***********
.. code-block:: none
This is a representation of the nRF21540 Radio Front-End module.
See the "nordic,nrf21540-fem-spi" binding to configure the SPI
interface. The SPI interface should be configured as a child node
of the SPI bus you have connected to the FEM. Then you "connect"
the FEM and SPI configurations using the spi-if property.
Here is an example nRF21540 configuration with a SPI interface
selected, using the SPIM0 peripheral found on several nRF5 SoCs:
&spi0 {
compatible = "nordic,nrf-spim";
status = "okay";
cs-gpios = <&gpio1 3 GPIO_ACTIVE_LOW>;
/* ... MISO/MOSI/SCK pin configuration goes here ... */
my_spi_if: nrf21540-spi@0 {
compatible = "nordic,nrf21540-fem-spi";
reg = <0>;
spi-max-frequency = <8000000>;
};
};
nrf_radio_fem: nrf21540 {
compatible = "nordic,nrf21540-fem";
tx-en-gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
rx-en-gpios = <&gpio0 5 GPIO_ACTIVE_HIGH>;
spi-if = <&my_spi_if>;
pdn-gpios = <...>;
ant-sel-gpios = <...>;
mode-gpios = <...>;
/* ... other nRF21540 properties go here ... */
};
&radio {
fem = <&nrf_radio_fem>;
};
In the above example, the nRF21540 is configured for use with:
- TX_EN on P0.2 (from 'tx-en-gpios')
- RX_EN on P0.5 (from 'rx-en-gpios')
- SPI communication via SPIM0 (the bus, or parent node, of
the 'my_spi_if' node
- CSN on P1.3 (from index 0 in the bus node's 'cs-gpios' property)
You must perform any additional required SPI pin configuration
(nRF21540 MISO, MOSI, and SCK pins) within the SPI bus node
('spi0' in the above example). See your SPI node's binding for
details on these pin mux properties. You can use any SPI node
available in your SoC's devicetree.
Configure any other nRF21540 pins as needed using 'pdn-gpios',
'ant-sel-gpios', and 'mode-gpios' properties. If unsure about the
format, use 'tx-en-gpios' as an example.
Finally, the nRF5 SoC's radio peripheral is set up for use with
the nRF21540 via the 'fem' property in the 'radio' node.
Properties
**********
.. tabs::
.. group-tab:: Node specific properties
Properties not inherited from the base binding file.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``tx-en-gpios``
- ``phandle-array``
- .. code-block:: none
GPIO of the SOC controlling TX_EN pin of the nRF21540
* - ``rx-en-gpios``
- ``phandle-array``
- .. code-block:: none
GPIO of the SOC controlling RX_EN pin of the nRF21540
* - ``pdn-gpios``
- ``phandle-array``
- .. code-block:: none
GPIO of the SOC controlling PDN pin of the nRF21540
* - ``ant-sel-gpios``
- ``phandle-array``
- .. code-block:: none
GPIO of the SOC controlling ANT-SEL pin of the nRF21540
* - ``mode-gpios``
- ``phandle-array``
- .. code-block:: none
GPIO of the SOC controlling MODE pin of the nRF21540
* - ``spi-if``
- ``phandle``
- .. code-block:: none
Reference to the nordic,nrf21540-fem-spi SPI bus interface.
This must be present to support SPI control of the FEM.
* - ``tx-en-settle-time-us``
- ``int``
- .. code-block:: none
Settling time in microseconds from state PG to TX.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: ``11``
* - ``rx-en-settle-time-us``
- ``int``
- .. code-block:: none
Settling time in microseconds from state PG to RX.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: ``11``
* - ``pdn-settle-time-us``
- ``int``
- .. code-block:: none
Settling time in microseconds from state PD to PG.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: ``18``
* - ``trx-hold-time-us``
- ``int``
- .. code-block:: none
Power-off time in microseconds when changing from RX or TX to PG.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: ``3``
* - ``supply-voltage-mv``
- ``int``
- .. code-block:: none
nRF21540 supply voltage in mV.
This is used if compensation for nRF21540 supply voltage is supported
by software.
.. group-tab:: Deprecated node specific properties
Deprecated properties not inherited from the base binding file.
(None)
.. group-tab:: 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,nrf21540-fem" compatible.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``status``
- ``string``
- .. code-block:: none
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 :ref:`zephyr:dt-important-props` for more information.
* - ``compatible``
- ``string-array``
- .. code-block:: none
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 :ref:`zephyr:dt-important-props` for more information.
* - ``reg``
- ``array``
- .. code-block:: none
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 :ref:`zephyr:dt-important-props` for more information.
* - ``reg-names``
- ``string-array``
- .. code-block:: none
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``
- .. code-block:: none
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 :ref:`zephyr:dt-important-props` for more information.
* - ``interrupts-extended``
- ``compound``
- .. code-block:: none
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``
- .. code-block:: none
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``
- .. code-block:: none
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``
- .. code-block:: none
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 :ref:`zephyr:dt-important-props` for more information.
* - ``clocks``
- ``phandle-array``
- .. code-block:: none
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``
- .. code-block:: none
Optional names given to each clock provider in the "clocks" property.
* - ``#address-cells``
- ``int``
- .. code-block:: none
This property encodes the number of 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``
- .. code-block:: none
This property encodes the number of 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``
- .. code-block:: none
DMA channel specifiers relevant to the device.
* - ``dma-names``
- ``string-array``
- .. code-block:: none
Optional names given to the DMA channel specifiers in the "dmas" property.
* - ``io-channels``
- ``phandle-array``
- .. code-block:: none
IO channel specifiers relevant to the device.
* - ``io-channel-names``
- ``string-array``
- .. code-block:: none
Optional names given to the IO channel specifiers in the "io-channels" property.
* - ``mboxes``
- ``phandle-array``
- .. code-block:: none
Mailbox / IPM channel specifiers relevant to the device.
* - ``mbox-names``
- ``string-array``
- .. code-block:: none
Optional names given to the mbox specifiers in the "mboxes" property.
* - ``power-domains``
- ``phandle-array``
- .. code-block:: none
Power domain specifiers relevant to the device.
* - ``power-domain-names``
- ``string-array``
- .. code-block:: none
Optional names given to the power domain specifiers in the "power-domains" property.
* - ``#power-domain-cells``
- ``int``
- .. code-block:: none
Number of cells in power-domains property
* - ``zephyr,deferred-init``
- ``boolean``
- .. code-block:: none
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
* - ``wakeup-source``
- ``boolean``
- .. code-block:: none
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``
- .. code-block:: none
Automatically configure the device for runtime power management after the
init function runs.
* - ``zephyr,disabling-power-states``
- ``phandles``
- .. code-block:: none
List of power states that will disable this device power.