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Date:   Mon, 5 Jul 2021 13:18:47 +0200
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     Discussions about the Letux Kernel <letux-kernel@openphoenux.org>,
        devicetree@vger.kernel.org, lars@metafoo.de,
        linux-pm@vger.kernel.org, linux-iio@vger.kernel.org,
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        leonard.crestez@nxp.com, lee.jones@linaro.org
Subject: Re: [Letux-kernel] [PATCH 0/4] mfd: rn5t618: Extend ADC support
Message-ID: <20210705131847.471d3ca5@aktux>
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On Sun, 4 Jul 2021 17:10:23 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> On Sat, 3 Jul 2021 18:55:40 +0200
> Andreas Kemnade <andreas@kemnade.info> wrote:
> 
> > On Sat, 3 Jul 2021 18:39:40 +0200
> > Andreas Kemnade <andreas@kemnade.info> wrote:
> >   
> > > Hi,
> > > 
> > > On Sat, 3 Jul 2021 16:59:50 +0100
> > > Jonathan Cameron <jic23@kernel.org> wrote:
> > >     
> > > > On Sat,  3 Jul 2021 10:42:20 +0200
> > > > Andreas Kemnade <andreas@kemnade.info> wrote:
> > > >       
> > > > > Add devicetree support so that consumers can reference the channels
> > > > > via devicetree, especially the power subdevice can make use of that
> > > > > to provide voltage_now properties.        
> > > > 
> > > > Does the mapping vary from board to board?  Often these mappings are
> > > > internal to the chip so might as well be provided hard coded in the
> > > > relevant drivers rather than via DT. See drivers that have iio_map
> > > > structure arrays.
> > > >       
> > > Most things are internal to the chip, but 
> > > AIN1/AIN0 are external and could be connected to anything.
> > >     
> > hmm, iio_map stuff looks nice, so before messing with devicetree,
> > I could solve 90% of the problem by just using iio_map? For my use
> > cases it is enough to have the internal stuff at the moment. That would
> > simplify stuff a lot.
> > 
> > So I could go forward with the iio_map stuff now, and if there is a use
> > case for AIN1/0, the devicetree stuff can be added later?  
> 
> I was just thinking the same.  I 'think' that it will first try to find
> a mapping via device tree and then use the iio_map stuff.
> 
> So you can probably get away with a mixture of the two.
> Worth testing that works though (hook up iio-hwmon to AIN0 perhaps whilst
> also using the iio_map approach).
> 
> I might be completely wrong though and am not aware of anyone currently
> doing this...
> 
I tested that approach, It works, so I will first post a series with
just the iio_map stuff and later the devicetree stuff.

Regards,
Andreas