[meta-xilinx] External XADC sources for zc702-zynq7 via device-tree

[Giordon Stark]

Hi all,

Following one of the xilinx forum posts here --
https://forums.xilinx.com/t5/Embedded-Processor-System-Design/Zynq-zc706-XADC-Reading-External-Voltages/td-p/593620
--
I wanted to plug in external sources for the xadc to monitor, so I made a
patch like so:

https://github.com/kratsg/meta-l1calo/blob/patch/externalXADC/recipes-bsp/u-boot/files/0001-add-external-xadc-to-device-tree.patch


diff --git a/arch/arm/dts/zynq-7000.dtsi b/arch/arm/dts/zynq-7000.dtsi
index 57a7474..8d136af 100644
--- a/arch/arm/dts/zynq-7000.dtsi
+++ b/arch/arm/dts/zynq-7000.dtsi
@@ -76,6 +76,23 @@
  interrupts = <0 7 4>;
  interrupt-parent = <&intc>;
  clocks = <&clkc 12>;
+
+ xlnx,channels {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ channel at 0{
+ reg = <0>;
+ };
+ channel at 1{
+ reg = <1>;
+ };
+ channel at 2{
+ reg = <2>;
+ };
+ channel at 8{
+ reg = <8>;
+ };
+ };
  };

  can0: can at e0008000 {


which is patched via u-boot-xlnx recipe

SRC_URI_append_zc702-zynq7 +=
"file://0001-add-external-xadc-to-device-tree.patch"

Part of me is a little suspicious that I patch it through u-boot-xlnx
instead of device-tree, but I guess part of that is because the dtsi files
are actually part of upstream u-boot by now...

In any case, a core-image builds just fine, however the kernel doesn't seem
to indicate that it's changed:

root at zc702-zynq7:~# ls /proc/device-tree/amba/adc at f8007100/
clocks            compatible        interrupt-parent  interrupts
name              reg
root at zc702-zynq7:~# ls /sys/devices/soc0/amba/f8007100.adc/iio\:device0/
dev                        in_temp0_raw
 in_voltage0_vccint_scale   in_voltage2_vccbram_raw
in_voltage3_vccpint_scale  in_voltage5_vccoddr_raw
in_voltage6_vrefp_scale    name                       sampling_frequency
events                     in_temp0_scale
 in_voltage1_vccaux_raw     in_voltage2_vccbram_scale
in_voltage4_vccpaux_raw    in_voltage5_vccoddr_scale
in_voltage7_vrefn_raw      of_node                    subsystem
in_temp0_offset            in_voltage0_vccint_raw
 in_voltage1_vccaux_scale   in_voltage3_vccpint_raw
in_voltage4_vccpaux_scale  in_voltage6_vrefp_raw
in_voltage7_vrefn_scale    power                      uevent

where I expect to be able to see something like in_voltage8 or something
new -- but I don't. Have I messed up the counting somehow?

Thanks,

Giordon
-- 
Giordon Stark
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