Re: [PATCH v4 2/3] hwmon: ltc4283: Add support for the LTC4283 Swap Controller

["Nuno Sá" <noname.nuno@gmail.com>]

On Fri, 2025-12-12 at 08:46 -0800, Guenter Roeck wrote:
> On 12/12/25 08:34, Nuno Sá wrote:
> > On Sat, 2025-12-06 at 10:40 -0800, Guenter Roeck wrote:
> > > On 12/4/25 08:15, Nuno Sá via B4 Relay wrote:
> > > > From: Nuno Sá <nuno.sa@analog.com>
> > > > 
> > > > Support the LTC4283 How Swap Controller. The device features programmable
> > > > current limit with foldback and independently adjustable inrush current to
> > > > optimize the MOSFET safe operating area (SOA). The SOA timer limits MOSFET
> > > > temperature rise for reliable protection against overstresses.
> > > > 
> > > > An I2C interface and onboard ADC allow monitoring of board current,
> > > > voltage, power, energy, and fault status.
> > > > 
> > > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > > 
> > > I finally found the time to write module test code for the driver.
> > > 
> > 
> > Thanks!
> > 
> > > Some early feedback:
> > > 
> > > - The driver must work with non-devicetree systems and without device
> > >     property support. Select defaults where necessary.
> > 
> > I'll double check that... But one thing that already comes to mind is rsense? Rsense
> 
> Yes.
> 
> > is the main design choice for a thing like this. Not sure we can decide on a meaningful
> > default for it? I believe we have the same situation for ltc4282.c
> > 
> 
> Agreed, but that doesn't make it better (and I don't have a unit test for that chip).
> Default would be your call. I usually go for 1 mOhm.
> 
> If you have access to it, can you send me a register dump for LTC4282 ?

I'm doing home office these days and I'm not sure I brought that chip with me. If I have
it, I'll do it!

> 
> > > - Attributes marked as readable in the is_visible function must be readable.
> > >     It is not acceptable to return -EOPNOTSUPP. That applies to all
> > >     reset_history attributes and maybe to others.
> > 
> > Hmm that's a mistake. They should be WO and I have the same bug in ltc4282 so I need to
> > send a patch.
> > 
> 
> ... which helps explain why I want to be able to run unit tests (which requires defaults).
> 

Makes sense. But from a dt bindings point of view, I assume we should still keep it as a
mandatory property?

- Nuno Sá