Dealing with the in-kernel IIO consumer interface

So far, we have dealt with the user-space consumer interface since data was consumed in user space. There are situations where a driver will require a dedicated IIO channel. An example is a battery charger that needs to measure the battery voltage as well. This measurement can be achieved using a dedicated IIO channel.

IIO channel attribution is done in the device tree. From the producer side, only one thing must be done: specifying the #io-channel-cells property according to the number of channels of the IIO device. Typically, it is 0 for nodes with a single IIO output and 1 for nodes with multiple IIO outputs. The following is an example:

adc: max1139@35 {
    compatible = "maxim,max1139";
    reg = <0x35>;
    #io-channel-cells = <1>;
};

On the consumer side, there are a few properties to provide. These are the following:

• io-channels...