From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Andrew F. Davis" Subject: Re: [PATCH 2/2] iio: afe: unit-converter: add support for adi,lt6106 Date: Thu, 12 Apr 2018 10:35:57 -0500 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4aac6870-9159-18ba-0aa8-da227c426f38@axentia.se> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Peter Rosin , Lars-Peter Clausen , linux-kernel@vger.kernel.org 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 , linux-iio@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org 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. >> 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" ? Andrew > Cheers, > Peter >