Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

This implements default-state support as described in:

https://www.kernel.org/doc/Documentation/devicetree/bindings/leds/leds-gpio.txt

Without this booting the VSATV102 causes the blue "working" led to turn
off when the kernel starts up. With this the led (which is turned on by
the firmware) stays on since that's the default state specified in the FDT.

Expanded the meaning of the led_create_state state parameter in order
to implement support for "keep". The original values were:

== 0 Off
!= 0 On

The new values are:

== -1 don't change / keep current setting
== 0 Off
!= -1 && != 0 On

This should have no effect on acpi_asus_attach which only calls
led_create_state with state set to 1. Updated acpi_ibm_attach
in order to avoid surprises.

Differential Revision: https://reviews.freebsd.org/D2615
Submitted by: John Wehle
Reviewed by: gonzo, loos

MFcalloutng:
Make led(4) fire callouts at 10Hz only when there is at least one LED that
is requested to blink. Do not fire if all LEDs are static (usual case).

MFgraid/head r218174:
Add simple in-kernel API for controlling leds.

Fix an incorrect use of sbuf_overflowed() after a call to sbuf_finish().

(S)LIST_HEAD_INITIALIZER takes a (S)LIST_HEAD as an argument.
Fix some wrong usages.
Note: this does not affect generated binaries as this argument is not used.

PR: 137213
Submitted by: Eygene Ryabinkin (initial version)
MFC after: 1 month

Remove unit2minor() use from kernel code.

When I changed kern_conf.c three months ago I made device unit numbers
equal to (unneeded) device minor numbers. We used to require
bitshifting, because there were eight bits in the middle that were
reserved for a device major number. Not very long after I turned
dev2unit(), minor(), unit2minor() and minor2unit() into macro's.
The unit2minor() and minor2unit() macro's were no-ops.

We'd better not remove these four macro's from the kernel, because there
is a lot of (external) code that may still depend on them. For now it's
harmless to remove all invocations of unit2minor() and minor2unit().

Reviewed by: kib

Add sbuf_new_auto as a shortcut for the very common case of creating a
completely dynamic sbuf.

Obtained from: Varnish
MFC after: 2 weeks

Remove the distinction between device minor and unit numbers.

Even though we got rid of device major numbers some time ago, device
drivers still need to provide unique device minor numbers to make_dev().
These numbers are only used inside the kernel. They are not related to
device major and minor numbers which are visible in devfs. These are
actually based on the inode number of the device.

It would eventually be nice to remove minor numbers entirely, but we
don't want to be too agressive here.

Because the 8-15 bits of the device number field (si_drv0) are still
reserved for the major number, there is no 1:1 mapping of the device
minor and unit numbers. Because this is now unused, remove the
restrictions on these numbers.

The MAXMAJOR definition was actually used for two purposes. It was used
to convert both the userspace and kernelspace device numbers to their
major/minor pair, which is why it is now named UMINORMASK.

minor2unit() and unit2minor() have now become useless. Both minor() and
dev2unit() now serve the same purpose. We should eventually remove some
of them, at least turning them into macro's. If devfs would become
completely minor number unaware, we could consider using si_drv0 directly,
just like si_drv1 and si_drv2.

Approved by: philip (mentor)

Make it possible to specify an initial state for the LED.

Requested by: Henrik Brix Andersen <henrik@brixandersen.dk>
PR: 112008

Add placeholder mutex argument to new_unrhdr().

Make a bunch of malloc types static.

Found by: src/tools/tools/kernxref

Better locking.

Add 'u' and 'U' "wait for next UTC second" in sequence mode.

Remove a pointless check.

Second half of the dev_t cleanup.

The big lines are:
NODEV -> NULL
NOUDEV -> NODEV
udev_t -> dev_t
udev2dev() -> findcdev()

Various minor adjustments including handling of userland access to kernel
space struct cdev etc.

Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.

- Remove the __FBSDID and put the $FreeBSD$ tag in the comment above,
so that including this file more than once works.
- Fix some style bugs while I'm here.

Fix off by one error.

Add the ability to avoid repetition of s.... sequences with a '.'

Device megapatch 4/6:

Introduce d_version field in struct cdevsw, this must always be
initialized to D_VERSION.

Flip sense of D_NOGIANT flag to D_NEEDGIANT, this involves removing
four D_NOGIANT flags and adding 145 D_NEEDGIANT flags.

Use standard style for cdevsw initialization.

DUH!

Write 100 times for tomorrow:
I will never again free(9) a modified pointer.

Pointy Hat: yeah, yeah, yeah, can you just put it in the pile over there...

Correct usage of mtx_init() API. This is not a functional change since
the code happened to work because MTX_DEF and NULL are both defined as 0.

Reviewed by: phk

Improve semantics of the 'sequence' command to led(4) devices:
use lowercase for off and upper case for on.

Approved by: re@

Avoid NULL pointer dereference.

Approved by: re@

Fix prototypo

Get word spacing right in morse mode.
Fix a prototype.

Add a generic LED driver for flashing lamps.

The hardware driver decides the name under /dev/led and provides
the function to turn the lamp on/off.

All leds are serviced by a single timeout which runs at a basic rate
of hz/10.

The LED is controlled by ascii strings as follows.

0 Turn off.
1 Turn on.
f Flash: _-
f2 Flash: __--
f3 Flash: ___---
f4...f9 etc.
d%d Digits. "d12": -__________-_-______________________________
s%s String, roll your own:
'a-j' gives on for (1...10)/10 sec.
'A-J' gives on for (1...10)/10 sec.
'sAaAbBa': _-_--__-
m%s Morse
'.' dot
'-' dash
' ' letter space
'\n' word space

My mdoc skills do not reach to express that.