From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48AG0Avk+GA3XYvN8xPhWAVGlvnR6KOsFafF02hPDqDCnzIIVq/mehoenMqiu9yBJQgVtH3 ARC-Seal: i=1; a=rsa-sha256; t=1523630878; cv=none; d=google.com; s=arc-20160816; b=YM/jM/NFOZu8TbD+hUOUXjXkF8d3CVRAQ+lTsE5wU4s3QM9QZUSfam3lzV4H8GzQP9 IChs5I2uFMA3aoXKjgvtHaRhINGS639X28mikeHOmUZ6TF6XNeEuNlmaIVG0I6F14N98 CxT1nndtITDUdiOt6dH8g4tlwT/oFqjoHl0UTKq2vyWwWk87xVlBZLTvkW2jVRWqbpmz MqLeKrjPZDcx9DB5N7IUlhTWs7Udc4xC9BFzk4m7Di9Nib1gRCT0q4gjsKLyYTjeCAf5 kVPkdmUNrHNPEFXsvfGe1pN6XhcOoBdSwUutyqP8DRPXIV71CFRdrk6ykWoQFPMpZw4S Zn+w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :dkim-signature:arc-authentication-results; bh=DOzrMyOjQVJ3JzP5a6ssz5mniZ4SiFsNWiA/y2GKlrI=; b=ZYYLH4uA4cjr20lglwulAzuVKAi/Y+yQOuWgcyLgW2zJDdR2L6uLAjG29e9xhY6155 03d/uHu6t0VVG8+xKprC1x8bIz/Igmg7LwfdVmXNbRx/jgkz5zmjr1EnvZM8Ej8WSxWC QMrzTl16P5OoN/jvtR2MXdAOZohlItj0+0AjClw1ileO9p3RioT+htJ8WMXEQGcDAVPe k3uhKdEMNSebyMtG9bp/eGFf5M8jVAMs9Lhf4WI7VlVXYE+cEqm/tOKJXIx1lqDZPecz 6ZEncp6JddTsv/p4bVTQwLnCPY/Jk5g6eAY0FoWeuKN30i+HEAZ6VaKKf3bcDJp1AW5V OkmA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=Ctk54aLU; spf=pass (google.com: domain of afd@ti.com designates 198.47.27.80 as permitted sender) smtp.mailfrom=afd@ti.com; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Authentication-Results: mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=Ctk54aLU; spf=pass (google.com: domain of afd@ti.com designates 198.47.27.80 as permitted sender) smtp.mailfrom=afd@ti.com; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Subject: Re: [PATCH 2/2] iio: afe: unit-converter: add support for adi,lt6106 To: Peter Rosin , Lars-Peter Clausen , CC: Jonathan Cameron , Hartmut Knaack , Peter Meerwald-Stadler , Rob Herring , Mark Rutland , "David S. Miller" , Greg Kroah-Hartman , Mauro Carvalho Chehab , Linus Walleij , Andrew Morton , Randy Dunlap , Fabio Estevam , , References: <20180410152802.30958-1-peda@axentia.se> <20180411141555.15044-1-peda@axentia.se> <20180411141555.15044-3-peda@axentia.se> <5d9421cc-5c7b-fcdf-a11f-e97127a3d5bd@metafoo.de> <19aeb920-ce5a-4e81-1264-9005e220c237@ti.com> <4aac6870-9159-18ba-0aa8-da227c426f38@axentia.se> <36e0c96b-89ec-2372-825a-71ead1a43473@axentia.se> From: "Andrew F. Davis" Message-ID: Date: Fri, 13 Apr 2018 09:47:30 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <36e0c96b-89ec-2372-825a-71ead1a43473@axentia.se> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597459598272065653?= X-GMAIL-MSGID: =?utf-8?q?1597642772617434867?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 04/12/2018 05:31 PM, Peter Rosin wrote: > On 2018-04-12 17:35, Andrew F. Davis wrote: >> On 04/12/2018 09:29 AM, Peter Rosin wrote: >>> On 2018-04-11 18:13, Andrew F. Davis wrote: >>>> On 04/11/2018 10:51 AM, Lars-Peter Clausen wrote: >>>>> On 04/11/2018 05:43 PM, Andrew F. Davis wrote: >>>>>> On 04/11/2018 09:15 AM, Peter Rosin wrote: >>>>>>> This is a current sense amplifier from Analog Devices. >>>>>>> >>>>>>> Signed-off-by: Peter Rosin >>>>>>> --- >>>>>>> drivers/iio/afe/Kconfig | 3 +- >>>>>>> drivers/iio/afe/iio-unit-converter.c | 54 ++++++++++++++++++++++++++++++++++++ >>>>>>> 2 files changed, 56 insertions(+), 1 deletion(-) >>>>>>> >>>>>>> diff --git a/drivers/iio/afe/Kconfig b/drivers/iio/afe/Kconfig >>>>>>> index 642ce4eb12a6..0e10fe8f459a 100644 >>>>>>> --- a/drivers/iio/afe/Kconfig >>>>>>> +++ b/drivers/iio/afe/Kconfig >>>>>>> @@ -10,7 +10,8 @@ config IIO_UNIT_CONVERTER >>>>>>> depends on OF || COMPILE_TEST >>>>>>> help >>>>>>> Say yes here to build support for the IIO unit converter >>>>>>> - that handles voltage dividers and current sense shunts. >>>>>>> + that handles voltage dividers, current sense shunts and >>>>>>> + the LT6106 Current Sense Amplifier from Analog Devices. >>>>>> >>>>>> Could work better to split these out into separate drivers. Maybe a >>>>>> iio-shunt-resistor.c that does just voltage->current with the >>>>>> appropriate scaling. Then make a a separate lt6106.c. >>>>> >>>>> I don't think we need a separate driver here. There are tons of circuits >>>>> that all work the same way and all require the same properties. If we'd add >>>>> a driver for each of them we'd get buried in boilerplate code. >>>>> >>>> >>>> Fair enough, then it should at least be renamed to something generic >>>> like current-sense-amplifier, as you said lots of circuits do this, not >>>> just lt6106s. We will have then have support for: >>>> >>>> current-sense-amplifier >>>> current-sense-shunt >>>> voltage-divider >>> >>> For the compatible "current-sense-amplifier", I would advocate the >>> properties... >>> >>> sense-resistor-micro-ohms >>> sense-gain >>> >>> (or something close to that) >>> >>> ...and not input-resistor-ohms and output-resistor-ohms which are way >>> more particular to the LT6106. >>> >>> But as I said in the cover letter, I didn't go with sense-gain since I >>> thought I would end up with requests for non-integer gains. There is >>> yet to be a comment on the non-integer gain problem, and before there >>> is a path forward for that case, I'm reluctant. >>> >> >> Why not similar to what you had before with the resistor: >> >> sense-gain-multiplier >> sense-gain-divider >> >> if either are missing assume they are 1. > > Hmm, how about sense-gain for the normal integer case, and then divide > by sense-attenuation if needed? I.e. exactly the same functionality as > you describe, just different names. > I like these names, but I think gain/attenuation sound very analog and I would be tempted to assume they are floating point numbers or the units are logarithmic (dB). To prevent any more needless bike-shedding on my part I'd like to say either yours, mine, or Lars-Peter's suggestion all work for me. >>>> compatibles in this driver called "unit-converter" which is still a >>>> misnomer IMHO. >>> >>> I don't remember you having presented your preference, and I think >>> that goes against the established bike-shedding protocol? >>> >> >> True, how about "current-sense-from-voltage" ? > > Doesn't cover "voltage-divider" (and we don't need separate drivers > doing the exact same calculations, that's a maintenance nightmare). > The driver name doesn't have to cover every use, just more than the other name. > Cheers, > Peter >