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11 changes: 11 additions & 0 deletions Documentation/ABI/testing/sysfs-bus-iio-frequency
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What: /sys/bus/iio/devices/iio:deviceX/out_altvoltageY_frequency_resolution
KernelVersion: 6.20
Contact: linux-iio@vger.kernel.org
Description:
Stores channel Y frequency resolution/channel spacing in Hz for PLL
devices. The given value directly influences the operating mode when
fractional-N synthesis is required, as it derives values for
configurable modulus parameters used in the calculation of the output
frequency. It is assumed that the algorithm that is used to compute
the various dividers, is able to generate proper values for multiples
of channel spacing.
212 changes: 212 additions & 0 deletions Documentation/devicetree/bindings/iio/frequency/adi,adf41513.yaml
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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/frequency/adi,adf41513.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Analog Devices ADF41513 PLL Frequency Synthesizer

maintainers:
- Rodrigo Alencar <rodrigo.alencar@analog.com>

description:
The ADF41513 is an ultralow noise frequency synthesizer that can be used to
implement local oscillators (LOs) as high as 26.5 GHz in the upconversion and
downconversion sections of wireless receivers and transmitters. The ADF41510
supports frequencies up to 10 GHz.

https://www.analog.com/en/products/adf41510.html
https://www.analog.com/en/products/adf41513.html

Comment thread
rodrigo455 marked this conversation as resolved.
$ref: /schemas/spi/spi-peripheral-props.yaml#

properties:
compatible:
enum:
- adi,adf41510
- adi,adf41513

reg:
maxItems: 1

spi-max-frequency:
maximum: 25000000

clocks:
maxItems: 1
description: Clock that provides the reference input frequency.

avdd1-supply:
description: PFD and Up and Down Digital Driver Power Supply (3.3 V)

avdd2-supply:
description: RF Buffer and Prescaler Power Supply (3.3 V)

avdd3-supply:
description: N Divider Power Supply (3.3 V)

avdd4-supply:
description: R Divider and Lock Detector Power Supply (3.3 V)

avdd5-supply:
description: Sigma-Delta Modulator and SPI Power Supply (3.3 V)

vp-supply:
description: Charge Pump Power Supply (3.3 V)

enable-gpios:
description:
GPIO that controls the chip enable pin. A logic low on this pin
powers down the device and puts the charge pump output into
three-state mode.
maxItems: 1

lock-detect-gpios:
description:
GPIO for lock detect functionality. When configured for digital lock
detect, this pin will output a logic high when the PLL is locked.
maxItems: 1

adi,power-up-frequency-mhz:
minimum: 1000
maximum: 26500
default: 10000
description:
The PLL tunes to this frequency during the initialization sequence.
This property should be set to a frequency supported by the loop filter
and VCO used in the design. Range is 1 GHz to 26.5 GHz for ADF41513,
and 1 GHz to 10 GHz for ADF41510.

adi,reference-div-factor:
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 1
maximum: 32
default: 1
description:
Value for the reference division factor (R Counter). The driver will
increment R Counter as needed to achieve a PFD frequency within the
allowed range. High R counter values will reduce the PFD frequency, which
lowers the frequency resolution, and affects phase noise performance.
As it affects the PFD frequency, this value depends on the loop filter
design.

adi,reference-doubler-enable:
description:
Enables the reference doubler when deriving the PFD frequency.
The maximum reference frequency when the doubler is enabled is 225 MHz.
As it affects the PFD frequency, this value depends on the loop filter
design.
type: boolean

adi,reference-div2-enable:
description:
Enables the reference divide-by-2 function when deriving the PFD
frequency. As it affects the PFD frequency, this value depends on the
loop filter design.
type: boolean

adi,charge-pump-resistor-ohms:
minimum: 1800
maximum: 10000
default: 2700
description:
External charge pump resistor (R_SET) value in ohms. This sets the maximum
charge pump current along with the charge pump current setting.

adi,charge-pump-current-microamp:
description:
Charge pump current (I_CP) in microamps. The value will be rounded to the
nearest supported value. Range of acceptable values depends on the
charge pump resistor value, such that 810 mV <= I_CP * R_SET <= 12960 mV.
This value depends on the loop filter and the VCO design.

adi,logic-level-1v8-enable:
description:
Set MUXOUT and DLD logic levels to 1.8V. Default is 3.3V.
type: boolean

adi,phase-detector-polarity-positive-enable:
description:
Set phase detector polarity to positive. Default is negative.
Use positive polarity with non-inverting loop filter and VCO with
positive tuning slope, or with inverting loop filter and VCO with
negative tuning slope.
type: boolean

adi,lock-detector-count:
$ref: /schemas/types.yaml#/definitions/uint32
default: 64
description:
Sets the value for Lock Detector count of the PLL, which determines the
number of consecutive phase detector cycles that must be within the lock
detector window before lock is declared. Lower values increase the lock
detection sensitivity, while higher values provides a more stable lock
detection. Applications that consume the lock detect signal may require
different settings based on system requirements.
enum: [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]

adi,phase-resync-period-ns:
default: 0
description:
When this value is non-zero, enable phase resync functionality, which
produces a consistent output phase offset with respect to the input
reference. The value specifies the resync period in nanoseconds, used
to configure clock dividers with respect to the PFD frequency. This value
should be set to a value that is at least as long as the worst case lock
time, i.e., it depends mostly on the loop filter design.
Comment thread
rodrigo455 marked this conversation as resolved.

adi,le-sync-enable:
description:
Synchronizes Load Enable (LE) transitions with the reference signal to
avoid asynchronous glitches in the output. This is recommended when using
the PLL as a frequency synthesizer, where the reference signal will always
be present while the device is being configured. When using the PLL as a
frequency tracker, where the reference signal may be absent, LE sync
should be left disabled.
type: boolean

required:
- compatible
- reg
- clocks
- avdd1-supply
- avdd2-supply
- avdd3-supply
- avdd4-supply
- avdd5-supply
- vp-supply

unevaluatedProperties: false

examples:
- |
#include <dt-bindings/gpio/gpio.h>
spi {
#address-cells = <1>;
#size-cells = <0>;

pll@0 {
compatible = "adi,adf41513";
reg = <0>;
spi-max-frequency = <25000000>;
clocks = <&ref_clk>;
avdd1-supply = <&avdd1_3v3>;
avdd2-supply = <&avdd2_3v3>;
avdd3-supply = <&avdd3_3v3>;
avdd4-supply = <&avdd4_3v3>;
avdd5-supply = <&avdd5_3v3>;
vp-supply = <&vp_3v3>;
enable-gpios = <&gpio0 10 GPIO_ACTIVE_HIGH>;
lock-detect-gpios = <&gpio0 11 GPIO_ACTIVE_HIGH>;

adi,power-up-frequency-mhz = <15500>;
adi,charge-pump-current-microamp = <3600>;
adi,charge-pump-resistor-ohms = <2700>;
adi,reference-doubler-enable;
adi,lock-detector-count = <64>;
adi,phase-resync-period-ns = <0>;
adi,phase-detector-polarity-positive-enable;
adi,le-sync-enable;
};
};
...
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