Re: [PATCH 0/4] serdev: make serdev_device_write() more usable

On Wed, Nov 14, 2018 at 9:10 AM Johan Hovold [off-list ref] wrote:

This series make the synchronous serdev_device_write() helper more
usable by

        1) allowing drivers to pass a zero timeout to indicate that they
           want to wait forever;

        2) returning the number of bytes actually written (buffered)
           if the helper is interrupted;

        3) make the helper use interruptible wait so that the helper can
           be used on behalf of user space.

Finally, the two write functions are documented using kernel-doc.

Turns out I was using the wrong timeout for two gnss drivers that
expected the helper to wait indefinitely. I've fixed up those separately
(by using MAX_SCHEDULE_TIMEOUT for now), but for the helper to be usable
when using flow control we really want it to be interruptible.

Besides the two gnss drivers, there's currently only one other in-kernel
user of this helper and that driver (rave-sp) uses a non-zero timeout
and doesn't check the return value and therefore does not need to be
updated.

Note that this series depends on the two above mentioned GNSS fixes
(submitted for v4.20-rc3).

Johan


Johan Hovold (4):
  serdev: use zero to indicate infinite write timeout
  serdev: make synchronous write return bytes written
  serdev: make synchronous write helper interruptible
  serdev: document the write functions using kernel-doc

Other than the one nit, for the series:

Reviewed-by: Rob Herring <robh@kernel.org>