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Alternative could be, for example: >> >> int iio_backend_enable(struct iio_backend *back) >> { >> int ret; >> >> ret = iio_backend_op_call(back, enable); >> >> return ret == -EOPNOTSUPP ? 0 : ret; >> } > > I would prefer not to assume we can ignore the backend not supporting > the call. It opens up the question for other operations. > > My preferred way for this kind of fundamental operation (enabling/disabling) > would be to check with DT maintainers if we could have some kind of fixed-backend > (fixed in the sense the HW is present but not controlled by Linux) dummy device that > with implement a no-OP enable/disable(). There is also use cases for the always_on cap with a configurable non-dummy backend. Some applications are such that the driver should leave the enabling/disabling up to the user space consuming the data. For this case it's great to have the frontend leave the backend enable alone using this capability. thanks, Tomas > > - Nuno Sá