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Re: [PATCH] iio: adc: ti-ads7950: add GPIO support




On 2/9/19 11:00 AM, Jonathan Cameron wrote:
Nope.  This is a state lock used to protect against transitions between
different modes of the IIO device (buffered vs polled), it
isn't suitable for general use.

The driver should be modified to handle that correctly.
We have iio_claim_direct_mode etc that deal with the case
where a device can't do certain operations whilst in buffered
mode.  Note it can fail and should.

Seems there are more drivers still doing this than I thought.
If anyone is bored and wants to clean them out, that would be
most appreciated!

If you need locking to protect a local buffer or the device
state, define a new lock to do it with clearly documented
scope.

Just as a reminder, there is a use case for this particular
chip that requires buffered mode and direct mode at the same
time.

https://patchwork.kernel.org/patch/10539021/
https://patchwork.kernel.org/patch/10527757/