linux-kernel - Re: [PATCH v2 1/6] dt-bindings: iio: frequency: add adf41513

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Message-ID: <s2dy34ui3ed3ay3yp4dpar3vysbg7mtksfmlboj7izoa7mt2uk@lxsrakxmvke2>
Date: Sun, 21 Dec 2025 19:56:29 +0000
From: Rodrigo Alencar <455.rodrigo.alencar@...il.com>
To: Jonathan Cameron <jic23@...nel.org>, 455.rodrigo.alencar@...il.com
Cc: Krzysztof Kozlowski <krzk@...nel.org>, 
	Rodrigo Alencar <rodrigo.alencar@...log.com>, linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org, David Lechner <dlechner@...libre.com>, 
	Andy Shevchenko <andy@...nel.org>, Lars-Peter Clausen <lars@...afoo.de>, 
	Michael Hennerich <Michael.Hennerich@...log.com>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Jonathan Corbet <corbet@....net>
Subject: Re: [PATCH v2 1/6] dt-bindings: iio: frequency: add adf41513

On 25/12/21 03:56PM, Jonathan Cameron wrote:
> On Sat, 20 Dec 2025 18:05:34 +0000
> 455.rodrigo.alencar@...il.com wrote:
> 
> > Hi Krzystof,
> > 
> > thanks for taking a look into this again. It was my first patch it didn't want
> > to draw more attention or discussion to the V1 patch as it was declared not ready
> > at its very first review.
> > 
> > On 25/12/20 10:21AM, Krzysztof Kozlowski wrote:
> > > On Fri, Dec 19, 2025 at 12:34:48PM +0000, Rodrigo Alencar wrote:  
> > > > dt-bindings for ADF41513, an ultralow noise PLL frequency synthesizer that
> > > > can be used to implement local oscillators (LOs) as high as 26.5 GHz.
> > > > Most properties refer to existing PLL driver properties (e.g. ADF4350).  
> > >
> > > What is "existing PLL driver"? I know about motor drivers, but can you
> > > drive PLL?
> > >
> > > And how is ADF4350 related to this binding. I do not see ADF4350
> > > compatible here at all. Describe hardware, a real one.  
> > 
> > ADF4350 is an older one, and its bindings can be found at:
> > Documentation/devicetree/bindings/iio/frequency/adi,adf4350.yaml
> > It is a similar part, but yet very different.
> > 
> > >
> > > Nothing improved.
> > >
> > > You ignored comments, did not bother to respond to them and then sent
> > > the same.  
> > 
> > Sorry for not responding on the V1 thread, but the previous patch had to be reviewed internally
> > first. It is not true that nothing is improved, in fact, it has changed a lot, here are some notes:
> > * adi,power-up-frequency is not carrying the -hz postfix because it forces to be a uint32 by
> > the dt-bindings check. For that variable it needs to be uint64 as the part supports up to 26.5 GHz > 2^32
> 
> What granularity is necessary?  E.g. Could -mhz work here? It's already defined in dts schema for MHz.

That is a good point, granularity is needed when we want to compensate for a
offset flagged during a calibration. That part supports micro Hz resolution
with the dual-modulus support, but that is something I cant have it here.
Since the important thing for this property is to have a frequency in a range
supported by the loop-filter/VCO design, MHz should be fine.

> 
> > * The properties related to the reference input signal path: reference-div-factor, reference-doubler-enable
> > reference-div2-enable are declared here because they are constraints for the PFD frequency definition,
> > which is the frequency that the output signal is updated, important for the loop-filter and VCO design.
> > * added support for all different power supply regulators.
> > * adi,lock-detect-precision and adi,lock-detect-bias-microamp: removed, now set
> > with adf41513_set_ld_window() following datasheet recommendation
> > * adi,fast-lock-enable: removed, faster lock detect clock is set depending on the lock-detect-count value
> > * adi,phase-resync-enable, adi,12bit-clk-divider and adi,12bit-clk2-divider: removed, now set with
> > adf41513_set_phase_resync(), based on the t_sync (from the datasheet: Phase Resync section)
> > value determined by adi,phase-resync-period-ns, which is also bound to the loop filter design.
> > 
kind regards,
 
Rodrigo Alencar