linux/Documentation/ABI/testing/sysfs-bus-iio-frequency-adf4371
Stefan Popa 7f699bd149 iio: frequency: adf4371: Add support for ADF4371 PLL
The ADF4371 is a frequency synthesizer with an integrated voltage
controlled oscillator (VCO) for phase-locked loops (PLLs). The ADF4371
has an integrated VCO with a fundamental output frequency ranging from
4000 MHz to 8000 MHz. In addition, the VCO frequency is connected to
divide by 1, 2, 4, 8, 16, 32, or 64 circuits that allows the user to
generate radio frequency (RF) output frequencies as low as 62.5 MHz at
RF8x. A frequency multiplier at RF16x generates from 8 GHz to 16 GHz. A
frequency quadrupler generates frequencies from 16 GHz to 32 GHz at RF32x.
RFAUX8x duplicates the frequency range of RF8x or permits direct access to
the VCO output.

The driver takes the reference input frequency from the device tree and
uses it to calculate and maximize the PFD frequency (frequency of the phase
frequency detector). The PFD frequency is further used to calculate the
timeouts: synthesizer lock, VCO band selection, automatic level
calibration (ALC) and PLL settling time.

This initial driver exposes the attributes for setting the frequency and
enabling/disabling the different adf4371 channels.

Datasheet:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/adf4371.pdf

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-06-17 21:06:45 +01:00

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What: /sys/bus/iio/devices/iio:deviceX/out_altvoltageY_frequency
KernelVersion:
Contact: linux-iio@vger.kernel.org
Description:
Stores the PLL frequency in Hz for channel Y.
Reading returns the actual frequency in Hz.
The ADF4371 has an integrated VCO with fundamendal output
frequency ranging from 4000000000 Hz 8000000000 Hz.
out_altvoltage0_frequency:
A divide by 1, 2, 4, 8, 16, 32 or circuit generates
frequencies from 62500000 Hz to 8000000000 Hz.
out_altvoltage1_frequency:
This channel duplicates the channel 0 frequency
out_altvoltage2_frequency:
A frequency doubler generates frequencies from
8000000000 Hz to 16000000000 Hz.
out_altvoltage3_frequency:
A frequency quadrupler generates frequencies from
16000000000 Hz to 32000000000 Hz.
Note: writes to one of the channels will affect the frequency of
all the other channels, since it involves changing the VCO
fundamental output frequency.
What: /sys/bus/iio/devices/iio:deviceX/out_altvoltageY_name
KernelVersion:
Contact: linux-iio@vger.kernel.org
Description:
Reading returns the datasheet name for channel Y:
out_altvoltage0_name: RF8x
out_altvoltage1_name: RFAUX8x
out_altvoltage2_name: RF16x
out_altvoltage3_name: RF32x
What: /sys/bus/iio/devices/iio:deviceX/out_altvoltageY_powerdown
KernelVersion:
Contact: linux-iio@vger.kernel.org
Description:
This attribute allows the user to power down the PLL and it's
RFOut buffers.
Writing 1 causes the specified channel to power down.
Clearing returns to normal operation.