Re: [PATCH v1 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver bindings

[Guenter Roeck]

On 8/1/23 22:31, Delphine_CC_Chiu/WYHQ/Wiwynn wrote:
> > -----Original Message-----
> > From: Guenter Roeck <groeck7@xxxxxxxxx> On Behalf Of Guenter Roeck
> > Sent: Monday, July 24, 2023 11:22 AM
> > To: Delphine_CC_Chiu/WYHQ/Wiwynn <Delphine_CC_Chiu@xxxxxxxxxx>
> > Cc: patrick@xxxxxxxxx; Jean Delvare <jdelvare@xxxxxxxx>; Rob Herring
> > <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski
> > <krzysztof.kozlowski+dt@xxxxxxxxxx>; linux-i2c@xxxxxxxxxxxxxxx;
> > linux-hwmon@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH v1 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver
> > bindings
> >
> >    Security Reminder: Please be aware that this email is sent by an external
> > sender.
> >
> > On 7/23/23 19:12, Delphine_CC_Chiu/WYHQ/Wiwynn wrote:
> >
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    enum:
> > > > > +      - lltc,ltc4286
> > > > > +      - lltc,ltc4287
> > > >
> > > > There is no LTC4287, at least according to the Analog website.
> > > It has been announced on Analog Devices website.
> > > Please refer to this link:
> > > https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
> > analog.com%2Fen%2Fproducts%2Fltc2487.html%23product-overview&data=0
> > 5%7
> > >
> > C01%7CWayne_SC_Liu%40wiwynn.com%7Cd97a86a696a54f28a26408db8bf52
> > 23d%7Cd
> > >
> > a6e0628fc834caf9dd273061cbab167%7C0%7C0%7C638257657193005539%7C
> > Unknown
> > >
> > %7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haW
> > wiLCJ
> > >
> > XVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=XrdlzCyq0pcjfv3M6QNX73Ieux0w
> > rfNKzNvv
> > > HgVSH40%3D&reserved=0
> >
> > No, that is wrong. You are pointing to ltc2487, which is something completely
> > different.
>
> We have sent e-mail to query about the release date for LTC4287 chip.
> Analog Device reply that they will release this chip in last week of Sep, 2023.
> Please refer to the attachment to review their reply.

At least according to the driver code, LTC4286 and the LTC4287 are functionally
identical. I am kind of puzzled why you insist mentioning the not-yet-existing
LTC4287; instantiating LTC4287 as LTC4286 should work perfectly fine. LTC4287
can always be added as devicetree reference if/when it officially exists.

Care to explain ?

Note: If the chips are _not_ functionally identical, and a follow-up patch will
be needed to add full LTC4287 support to the driver after the chip has been
published, it would be inappropriate to make partial/incomplete changes now.
With that possibility in mind, I am not inclined to accept a driver that is
even mentioning LTC4287 without access to its datasheet because I think it
is important for me to understand the differences and similarities between
the two chips.

Guenter