>
> *On 7 November 2015 at 02:53, William Hermans <[email protected]
> <[email protected]>> wrote:*
>
>> *OK, thanks. That uio guide I've already run into, and I was afraid you
> were going to link to that . . . heh. Beaglebone register address I did
> not need help with, but understanding how to interface the uio adc "driver"
> once running.*
>
> *One problem I'm seeing thus far, is the ADC clock needs to be enabled
> etc. Which is in a completely different memory location . . . but my
> imagination is not that limited, so would not slow me down too much . . .*
> *Happens automagically when you open /dev/uio/adc (and the kernel will
> disable the clock again when you close it).*
>
> *The reason for that is that my DTS fragment reuses the existing DT node
> for the ADC. A standalone definition would be:*
>
> *tscadc@44e0d000 {
> reg = <0x44e0d000 0x1000>;
> interrupt-parent = <&intc>;
> interrupts = <16>;
> ti,hwmods = "adc_tsc";
> compatible = "uio";
> uio-alias = "adc";
> };*
>
> *The magic clock enabling part is due to "ti,hwmods", which associates the
> node with platform data still hardcoded into the kernel. I'm not entirely
> sure how the mechanism works exactly, and my understanding is that it's
> destined to become deprecated eventually ("replaced by genpd along the
> lines of simple-pm-bus"). I don't know how things will look after that.*
>
>
> *(the two child nodes declared in the main DT are ignored by uio and
> harmless)*
>
>
> Matthijs
>
> *PS although your reply was by direct email I'm sending this to the list
again since, although off-topic, I think it may still be of interest to
other readers.*
Matthijs,
So doing some digging, am33xxx.dtsi has this fragment:
tscadc: tscadc@44e0d000 {
compatible = "ti,am3359-tscadc";
reg = <0x44e0d000 0x1000>;
interrupt-parent = <&intc>;
interrupts = <16>;
ti,hwmods = "adc_tsc";
status = "disabled";
tsc {
compatible = "ti,am3359-tsc";
};
am335x_adc: adc {
#io-channel-cells = <1>;
compatible = "ti,am3359-adc";
};
};
So I am thinking the code snippet for the /dev/uio/adc would not work
without modifying that file to reflect those changes. Am I wrong ?
Everything, well most everything looks the same except for the compatible
field, status field is disabled instead of "ok", and you have an additional
field for a uio alias I suppose.
You had mentioned you do not use overlays. How do you enable all this then
? Perhaps I'd learn more from that.
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