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Wed, 08 Jul 2026 04:30:58 -0700 (PDT) Date: Wed, 8 Jul 2026 12:32:00 +0100 From: Nuno =?utf-8?B?U8Oh?= To: Krzysztof Kozlowski Cc: Guenter Roeck , Fred Chen , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Corbet , Shuah Khan , Jonathan Cameron , Wensheng Wang , Frank Li , Brian Chiang , Cosmo Chou , Dixit Parmar , Eddie James , Antoni Pokusinski , Thorsten Blum , Ashish Yadav , Alexis Czezar Torreno , Syed Arif , ChiShih Tsai , Abdurrahman Hussain , Kim Seer Paller , Colin Huang , Yuxi Wang , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH 2/2] hwmon: (pmbus) Add driver for Analog Devices MAX20912 and MAX20916 Message-ID: References: <20260707122701.751878-1-fredchen.openbmc@gmail.com> <20260707122701.751878-3-fredchen.openbmc@gmail.com> <20260708-true-carp-of-champagne-a0dcca@quoll> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260708-true-carp-of-champagne-a0dcca@quoll> On Wed, Jul 08, 2026 at 12:50:25PM +0200, Krzysztof Kozlowski wrote: > On Wed, Jul 08, 2026 at 10:19:56AM +0100, Nuno Sá wrote: > > On Tue, Jul 07, 2026 at 06:52:48AM -0700, Guenter Roeck wrote: > > > On 7/7/26 05:26, Fred Chen wrote: > > > > Add support for the Analog Devices MAX20912 and MAX20916 dual-output > > > > multiphase voltage regulators with PMBus interfaces. > > > > > > > > Signed-off-by: Fred Chen > > > > > > Please provide evidence that those chips actually exist. > > > Internet search comes up blank. I'll need confirmation > > > from someone at Analog. > > > > Hi Guenter, > > > > Well, in fact I'm in the middle of preparing a series that adds support > > for: > > > > "max20826" > > "max20855b" > > "max20908" > > "max20912" > > "max20916" > > > > All the above parts have the datasheet under NDA. But before we had a > > one page "datasheet" in analog.com but I guess that is gone! For context > > I mainly did the base (core) driver for max20826 and then Alexis added > > the other ones. > > > > Not sure how to proceed... I can wait and then work on top of what Fred > > has but this patch is very minimal when compared with what we have. > > Like: > > > > * No regulator support; > > * No direct mode. The chip has two ways to access registers (paging and > > * direct mode). > > * No way to count how many phases we have or if RAIL_B (func[1]) is being used at > > all. > > > > > > Some other things more intriguing is that these chips, as far as I'm > > aware (at least for max20826), always have bit 2 set in ON_OFF_CONFIG so > > a gpio vout. Also we needed some special handling to read phase current > > which I'm not seeing in the driver. So I would like to understand how > > the chip was tested? > > > > Anyways, if Fred is ok with it I can just finish what I'm doing and send > > the patches. It would make sense to have something more complete on > > submission but I don't want to just "steal" the work already done. > > Binding should be in such case posted complete, so probably not a > trivial device. Yes, in my series bindings are not in trivial as we support the enable gpios. - Nuno Sá