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nordic,nrf-radio¶

Vendor: Nordic Semiconductor

Description¶

Nordic nRF family RADIO peripheral.

This controls the 2.4 GHz radio transceiver on nRF5x
SoCs, which is available for use with Bluetooth, 802.15.4,
and proprietary wireless protocols (not all of these
protocols are available on all SoCs; consult the product
specifications for details).

This binding is not relevant to the nRF91x baseband radio.

Direction Finding Extension
---------------------------

Some radios support the Bluetooth Direction Finding Extension (DFE).
The 'dfe-supported' property will be set when it is available.
In this case, the 'dfegpio[n]-gpios' properties configure GPIO pins
to use to drive antenna switching.

Each dfegpio[n]-gpios property which is set is used to initialize the
corresponding PSEL.DFEGPIO[n] register.

None of the dfegpio[n]-gpios properties are marked 'required',
since which PSEL.DFEGPIO[n] registers will be used to drive
antenna switches depends on the use case. Nevertheless, at least two
antennas must be available to use DFE.

That in turn means that at least one dfegpio[n]-gpios
property must be provided if DFE is used, to give the radio the
possibility to switch between two antennas. To use 12 antennas,
4 GPIOs must be provided (since 4 GPIO pins support switching up to
16 antennas).

GPIOs are used in order, following the indices of the dfegpio[n]-gpios
properties. The order is important because it affects the mapping of
antenna switch patterns to GPIOs.

Antenna switching patterns
--------------------------

An antenna switching pattern is a binary number where each bit is
applied to a particular antenna GPIO pin. For example, the pattern
0x3 means that antenna GPIOs at indexes 0 and 1 will be set, while
the following are left unset.

The number of GPIOs specified with dfegpio[n]-gpios properties
affects the allowed pattern values. For example, when using four
GPIOs, the pattern count cannot be greater than 16, and the
maximum allowed value is 15.

Antenna switch patterns are stored in DFE internal memory by
writes to the SWITCHPATTERN register. DFE handling code applies
antenna switch patterns during Constant Tone Extension (CTE)
receive (Angle of Arrival mode) or transmission (Angle of
Departure mode) procedure.

DFE States
----------

There are four states of DFE operation:

* Idle: in this state, PDU transmission happens.
  DFE uses SWITCHPATTERN[0] to select the antenna in this state.
  (The 'dfe-pdu-antenna' property value described below is stored
  in SWITCHPATTERN[0] by the radio controller code.)

* Guard: in this state, DFE prepares for reception or transmission
  of CTE. For this state, DFE selects the antenna by applying
  SWITCHPATTERN[1].

* Reference: in this state, DFE starts to receive or transmit CTE.
  In AoA mode, DFE collects reference IQ samples. The selected
  antenna is the same as in the guard state.

* Switch-sample: in this state, actual antenna switching happens.
  DFE selects antennas by applying SWITCHPATTERN[2..N]. If the
  number of switch-sample periods is greater than the number of
  stored switching patterns, DFE loops back to SWITCHPATTERN[2].

Properties¶

Properties not inherited from the base binding file.

Name	Type	Details
`dfe-supported`	`boolean`	If set, the radio hardware supports the Direction Finding Extension. This property should be treated as read-only and should not be overridden; the correct value is provided for your target's SoC already.
`dfe-antenna-num`	`int`	Number of available antennas for the Direction Finding Extension. This should only be set if dfe-supported is true. If you set this property, the value must be at least two.
`dfe-pdu-antenna`	`int`	Antenna switch pattern to be used for transmission of PDU before start of transmission of Constant Tone Extension. This should only be set if dfe-supported is true. This pattern is stored in SWITCHPATTERN[0] before actual antenna switching patterns. This pattern will also be used to drive GPIOs when the radio releases control of GPIOs used to switch antennas.
`dfegpio0-gpios`	`phandle-array`	Pin select for DFE pin 0. This should only be set if dfe-supported is true. For example, to use P0.2 on an nRF5x SoC: dfegpio1-gpios = <&gpio0 2 0>; To use P1.4: dfegpio1-gpios = <&gpio1 4 0>; Note the last 'flags' cell in the property is not used, and should be set to 0 as shown.
`dfegpio1-gpios`	`phandle-array`	Pin select for DFE pin 1. See description for dfegpio0-gpios.
`dfegpio2-gpios`	`phandle-array`	Pin select for DFE pin 2. See description for dfegpio0-gpios.
`dfegpio3-gpios`	`phandle-array`	Pin select for DFE pin 3. See description for dfegpio0-gpios.
`dfegpio4-gpios`	`phandle-array`	Pin select for DFE pin 4. See description for dfegpio0-gpios.
`dfegpio5-gpios`	`phandle-array`	Pin select for DFE pin 5. See description for dfegpio0-gpios.
`dfegpio6-gpios`	`phandle-array`	Pin select for DFE pin 6. See description for dfegpio0-gpios.
`dfegpio7-gpios`	`phandle-array`	Pin select for DFE pin 7. See description for dfegpio0-gpios.

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-radio” compatible.

Name	Type	Details
`reg`	`array`	register space This property is required. See Important properties for more information.
`interrupts`	`array`	interrupts for device This property is required. See Important properties for more information.
`status`	`string`	indicates the operational status of a device Legal values: `'ok'`, `'okay'`, `'disabled'`, `'reserved'`, `'fail'`, `'fail-sss'` See Important properties for more information.
`compatible`	`string-array`	compatible strings This property is required. See Important properties for more information.
`reg-names`	`string-array`	name of each register space
`interrupts-extended`	`compound`	extended interrupt specifier for device
`interrupt-names`	`string-array`	name of each interrupt
`interrupt-parent`	`phandle`	phandle to interrupt controller node
`label`	`string`	Human readable string describing the device (used as device_get_binding() argument) See Important properties for more information.
`clocks`	`phandle-array`	Clock gate information
`clock-names`	`string-array`	name of each clock
`#address-cells`	`int`	number of address cells in reg property
`#size-cells`	`int`	number of size cells in reg property
`dmas`	`phandle-array`	DMA channels specifiers
`dma-names`	`string-array`	Provided names of DMA channel specifiers
`io-channels`	`phandle-array`	IO channels specifiers
`io-channel-names`	`string-array`	Provided names of IO channel specifiers
`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.