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

[Guenter Roeck <linux@roeck-us.net>]

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 ?

>> - 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).

Thanks,
Guenter