Re: [PATCH 1/5] iio: xoadc: augment DT bindings a bit

On Sun, Mar 26, 2017 at 6:57 AM, Bjorn Andersson
[off-list ref] wrote:

On Sat 18 Mar 06:33 PDT 2017, Linus Walleij wrote:

quoted

+adc-channel@0c {

Shouldn't the @ be followed by the value of the first cell in "reg"?
(Which will collide if we name them all "adc-channel").

I don't think we have a rule about these other than that they should
be unique. I renamed them so that it is unique using the combined
premux+amux number:

quoted

+     reg = <0x00 0x0c>;

So this becomes

adc-channel@000c {
    reg = <0x00 0x0c>;
};

quoted

+  On PM8058 the hardware only supports 16 channels, but we get the same
+  channels repeating with its input divided down by 1 or 3. Channels 00,
+  10, 20, ... f0 are the raw values, 04, 14, 24 .. f4 are "unity" channels
+  divided by 1, and 08, 18, 28 .. f8 are channels divided by 3. Bits 0
+  and 1 of the channel index should always be 0.
+
+  On PM8921 the hardware supports more than 16 channels through a complex
+  routing matrix using a premux, so 00, 10, 20 .. f0 are the basic raw
+  channels while another set of channels appear for 04, 14, 24 .. f4,
+  and again some of the same channels appear again divided down by 3
+  in 08, 18, 28 .. f8. Again bits 0 and 1 of the channel index should
+  always be 0.

While I believe documenting this is a good thing I do not think it adds
value to this binding document (other than showing Rob the absurdness of
the addressing scheme). Please consider moving it to the driver (haven't
checked how you commented it yet) and drop it from here.

Dropped it.

I'm sending this modified version as v2.

Yours,
Linus Walleij
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