Add support for adt7410 (module and overlay)

[aSmig]

The Analog Devices ADT7410 is a high precision temperature sensor with growing popularity. This PR seeks to add the module and overlay.

[aSmig]

File sizes are fairly small:
2.0K /boot/firmware/overlays/adt7410.dtbo
4.0K /lib/modules/6.1.61-v8+/kernel/drivers/hwmon/adt7410.ko.xz
4.0K /lib/modules/6.1.61-v8+/kernel/drivers/hwmon/adt7x10.ko.xz
10.0K total

[pelwell]

This needs a few small changes:

1. Without an entry in overlays/Makefile it won't be compiled and installed.
2. Don't include CONFIG_SENSORS_ADT7X10=m to the defconfigs - it is implied by CONFIG_SENSORS_ADT7410=m.

Otherwise it looks good.

[aSmig]

Thanks for the quick review! How is this? I appreciate the extra help.

[pelwell]

Looks good. I'll let the build checks run, squash them down to two commits, and merge offline.

[pelwell]

On second thoughts (first thought, if I'm honest), as this is such a simple overlay for an I2C-attached sensor, I'd rather add it to the i2c-sensor overlay. There's a new commit that adds adt7410 as a parameter - does that work for you?

[aSmig]

Putting this into i2c-sensor sounds very reasonable. Unfortunately I haven't been successful at testing this approach on my system.

$ sudo dtoverlay i2c-sensor adt7410 addr=0x4a
* Failed to apply overlay '0_i2c-sensor' (kernel)

The simpler adt7410.dtbo did load successfully. This is new territory for me so I'm not sure how to debug. I also tried loading i2c-sensors,adt7410,addr=0x4a via config.txt with no luck. I must be doing something wrong when compiling the i2c-sensor overlay, so here are my steps:

wget https://raw.githubusercontent.com/raspberrypi/linux/5f9c19e21de5ed2a57d5560698a4ce2440518f62/arch/arm/boot/dts/overlays/i2c-sensor-common.dtsi
cpp -nostdinc -I ~/linux/include -undef -x assembler-with-cpp i2c-sensor-common.dtsi i2c-sensor-common.dtsi.preprocessed
mv i2c-sensor-common.dtsi.preprocessed i2c-sensor-common.dtsi
cp ~/linux/arch/arm/boot/dts/overlays/i2c-sensor-overlay.dts .
dtc -O dtb i2c-sensor-common.dtsi -o i2c-sensor.dtbo
sudo cp i2c-sensor.dtbo /boot/overlays/

If you are confident that everything is fine and will just work with a complete kennel build, no need to help me troubleshoot my broken testing process. I'll trust you. Thanks again for your work!

[pelwell]

There was an unwanted underscore in one of the labels, which then ended up being undefined. I've tested and pushed a modified version. Until recently the dtoverlay command (not the config.txt directive) would fail because it lacked support for the newer overlay features - that should all be fixed in the latest version - but I think the i2c-sensor overlay is sufficiently simple that it would work even with older installs.

[pelwell]

By the way, I would have written your compilation step like this:

dtc -@ -Hepapr -I dts -O dtb -o i2c-sensor.dtbo i2c-sensor-overlay.dts

Some of the difference are cosmetic or nice-to-haves, but some of them (the -@, using the correct source file) are not.

[aSmig]

This is great, thanks! Your updated i2c-sensor-common.dtsi is working on my system when compiled correctly, thanks for the tips. Don't we still need CONFIG_SENSORS_ADT7410=m added to the configs?

[pelwell]

You're right - commit 057e09b added.

[aSmig]

Perfect. Thank you so much!