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Date:   Sun, 26 Jul 2020 13:50:59 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     "Pop, Cristian" <Cristian.Pop@analog.com>
Cc:     Lars-Peter Clausen <lars@metafoo.de>,
        "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] one-bit-adc-dac: Add initial version of one bit
 ADC, DAC
Message-ID: <20200726135059.1234aa71@archlinux>
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..
> >   
> > > > +	if (ret < 0)
> > > > +		return ret;
> > > > +
> > > > +	for (i = 0; i < num_ch; i++) {
> > > > +		channels[i] = (struct  
> > iio_chan_spec)ONE_BIT_ADC_DAC_CHANNEL(i +  
> > > > +							offset,
> > > > +							direction);
> > > > +		channels[i].extend_name = gpio_names[i];  
> > > I think we want to avoid using extend_name in new drivers because it
> > > makes for a very clumsy ABI. We should add a label property like we
> > > have for the device for channels to have a symbolic name of the channel.  
> The current dts looks like this:
> one-bit-adc-dac@0 {
> 				in-gpios = <&gpio 17 0>, <&gpio 27 0>;
> 				in-gpio-names = "i_17", "i_27";
> 				out-gpios = <&gpio 23 0>, <&gpio 24 0>;
> 				out-gpio-names = "o_23", "o_24";
> 			};
> Resulting in channels:
> in_voltage0_i_17_raw
> in_voltage1_i_27_raw
> out_voltage2_o_23_raw
> out_voltage3_o_24_raw
> If we want to lose extend_name, please provide an example for using labels.
> How the dts should look like, how do I use it in the driver?

Doesn't exist yet :)  Proposal was to add support for a label attribute
to the iio core.

If we were going to do a generic binding it would have to be part of the
existing channel bindings. e.g.
Documentation/devicetree/bindings/iio/adc/adc.txt

But here it might be fine to use the gpio-names to fill one in.
Alternative would be to use a binding where the gpio was specified
as part of the per channel child nodes rather than as a single entry.