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

[David Lechner]

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/