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Re: FDT conversion - do any IIC devices work on RPI 2



Hi Frank --

In FDT world we expect the device to be declared in the device tree as a child node of the I2C controller.

If you don't need anything special other than device address, your device can fit into this binding category:

https://www.kernel.org/doc/Documentation/devicetree/bindings/i2c/trivial-devices.txt

You'll need to modify the driver to match on your compatible string as well.

Normally you would need to modify your .dts, but in the Raspberry Pi case, you can tell the loader to load an overlay instead: https://www.raspberrypi.org/documentation/configuration/device-tree.md

Cheers,
Jared


On Sun, 1 Apr 2018, Frank Kardel wrote:

Hi !

I just tried to switch to 8.99.14 from 7.99.52 and found following surprises:

   hythygtemp* does not attach to iic?

Cause: indirect config does not work as an empty proplist seems be attached to iba->iba_child_devices in i2c.c:i2c_attach().

Ignoring empty proplists will allow hythygtemp to attach, but iic_exec returns errno=5 (EIO) - thus no values are obtained.

Do we have a driver problen for i2c here or do we need to change something in the hythygtemp driver to adjust to fdt.

Needless to say that everything works for with pre-fdt/pre-8.99 (7.99.52).

Frank





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