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([2600:1700:e321:62f0:da43:aeff:fecc:bfd5]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-31174accae5sm34245609eec.29.2026.07.08.11.32.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Jul 2026 11:33:01 -0700 (PDT) Sender: Guenter Roeck Message-ID: Date: Wed, 8 Jul 2026 11:32:58 -0700 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] hwmon: (pmbus) Add driver for Analog Devices MAX20912 and MAX20916 To: =?UTF-8?Q?Nuno_S=C3=A1?= , Krzysztof Kozlowski Cc: 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 References: <20260707122701.751878-1-fredchen.openbmc@gmail.com> <20260707122701.751878-3-fredchen.openbmc@gmail.com> <20260708-true-carp-of-champagne-a0dcca@quoll> Content-Language: en-US From: Guenter Roeck Autocrypt: addr=linux@roeck-us.net; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 7/8/26 04:32, Nuno Sá wrote: > 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. > Same question I asked before: What is your use case ? Thanks, Guenter