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Johan Hovold c3bf40ce2c serdev: add controller runtime PM support
Add support for controller runtime power management to serdev core. This
is needed to allow slave drivers to manage the runtime PM state of the
underlying serial controller when its driver, in turn, implements more
aggressive runtime power management (e.g. using autosuspend).

For some applications, for example, where loss off initial data after a
remote-wakeup event is acceptable or where rx is not used at all,
aggressive serial controller runtime PM may be used without further
involvement of the slave driver. But when this is not the case, the
slave driver must be able to indicate when incoming data is expected in
order to avoid data loss.

To facilitate the common case, where the serial controller power state
is active whenever the port is open (which is the case with just about
every serial driver), and where data loss is not acceptable and cannot
even be prevented by explicit controller runtime power management, an
RPM reference is taken in serdev open and put again at close. This
reference can later be balanced by any serdev driver which wants and/or
can handle aggressive controller runtime PM.

Note that the .ignore_children flag is set for the serdev controller to
allow the underlying hardware to idle when no I/O is expected, regardless
of the slave device RPM state.

Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-28 21:07:54 +09:00
arch Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-24 20:29:15 +08:00
block for-linus-20180623 2018-06-24 06:33:54 +08:00
certs docs: Fix some broken references 2018-06-15 18:10:01 -03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-06-24 06:31:54 +08:00
Documentation dt-bindings: serial: imx: clarify rs485 support usage 2018-06-28 21:02:38 +09:00
drivers serdev: add controller runtime PM support 2018-06-28 21:07:54 +09:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs \n 2018-06-22 18:04:56 +09:00
include Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-24 20:18:19 +08:00
init dma-mapping: move all DMA mapping code to kernel/dma 2018-06-14 08:50:37 +02:00
ipc ipc: use new return type vm_fault_t 2018-06-15 07:55:25 +09:00
kernel Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-24 20:29:15 +08:00
lib Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-24 19:36:16 +08:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
mm for-linus-20180623 2018-06-24 06:33:54 +08:00
net NFS client bugfixes for Linux 4.18 2018-06-22 06:21:34 +09:00
samples VFIO updates for v4.18 2018-06-12 13:11:26 -07:00
scripts tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcount 2018-06-21 15:12:56 -04:00
security docs: Fix some broken references 2018-06-15 18:10:01 -03:00
sound docs: Fix some broken references 2018-06-15 18:10:01 -03:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-24 20:29:15 +08:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM: arm64: Prevent KVM_COMPAT from being selected 2018-06-21 17:17:50 +01:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge branch 'asoc-4.17' into asoc-4.18 for compress dependencies 2018-04-26 12:24:28 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: add basic helper macros to scripts/Kconfig.include 2018-05-29 03:31:19 +09:00
MAINTAINERS Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-24 19:59:52 +08:00
Makefile Linux 4.18-rc2 2018-06-24 20:54:29 +08:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.