workq in Kernel primer for unified kernel

[zephyrbot]

Reported by Sharron LIU:

Probably this has been considered, if yes, please duplicate it.
[~ajnebnim] you may decide if this should be converted to a story or a sub-task of it.

As it was concluded "Workqueues will be brought in as a first-class unified kernel object", then as a tester or developer using workqueue, I would like to learnt how to use it from kernel doc, like https://gerrit.zephyrproject.org/r/#/c/4511
Interested questions like,

• how to re-submit (or repeatedly execute) a work item?
• in kernel v1 the "nano_work.h" mentioned "the work is considered complete and can be resubmitted", what is the API for app to be aware the work is "complete"?

  it looks that there's no API indication of "complete". re-submitting is invoking "nano_work_submit()" again from the handler of a work item. It would be helpful if this is explained and provided sample codes in the kernel doc.

• is adding new work item allowed after started a work queue?

(Imported from Jira ZEP-1023)

[zephyrbot]

by Allan Stephens:

Workqueues are now documented in the Kernel Primer, under "Workqueue Threads".

[zephyrbot]

by Inaky Perez-Gonzalez:

Verified.