sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Fix some common typos in comments

- s/configuraiton/configuration/
- s/specifed/specified/
- s/compatiblity/compatibility/

MFC after: 5 days

MFhead@r323635

MFH @ r323558.

Add gpio methods to read/write/configure up to 32 pins simultaneously.

Sometimes it is necessary to combine several gpio pins into an ad-hoc bus
and manipulate the pins as a group. In such cases man

Add gpio methods to read/write/configure up to 32 pins simultaneously.

Sometimes it is necessary to combine several gpio pins into an ad-hoc bus
and manipulate the pins as a group. In such cases manipulating the pins
individualy is not an option, because the value on the "bus" assumes
potentially-invalid intermediate values as each pin is changed in turn. Note
that the "bus" may be something as simple as a bi-color LED where changing
colors requires changing both gpio pins at once, or something as complex as
a bitbanged multiplexed address/data bus connected to a microcontroller.

In addition to the absolute requirement of simultaneously changing the
output values of driven pins, a desirable feature of these new methods is to
provide a higher-performance mechanism for reading and writing multiple
pins, especially from userland where pin-at-a-time access incurs a noticible
syscall time penalty.

These new interfaces are NOT intended to abstract away all the ugly details
of how gpio is implemented on any given platform. In fact, to use these
properly you absolutely must know something about how the gpio hardware is
organized. Typically there are "banks" of gpio pins controlled by registers
which group several pins together. A bank may be as small as 2 pins or as
big as "all the pins on the device, hundreds of them." In the latter case, a
driver might support this interface by allowing access to any 32 adjacent
pins within the overall collection. Or, more likely, any 32 adjacent pins
starting at any multiple of 32. Whatever the hardware restrictions may be,
you would need to understand them to use this interface.

In additional to defining the interfaces, two example implementations are
included here, for imx5/6, and allwinner. These represent the two primary
types of gpio hardware drivers. imx6 has multiple gpio devices, each
implementing a single bank of 32 pins. Allwinner implements a single large
gpio number space from 1-n pins, and the driver internally translates that
linear number space to a bank+pin scheme based on how the pins are grouped
into control registers. The allwinner implementation imposes the restriction
that the first_pin argument to the new functions must always be pin 0 of a
bank.

Differential Revision: https://reviews.freebsd.org/D11810

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Merge sync of head

Merge from HEAD

Merge ^/head r277975 through r277998.

Implement a new method to retrieve the gpiobus reference from a GPIO
controller.

The gpiobus is responsible to keep track of the used pins and serialize
the access to pins.

Some of these features a

Implement a new method to retrieve the gpiobus reference from a GPIO
controller.

The gpiobus is responsible to keep track of the used pins and serialize
the access to pins.

Some of these features are important to devices that do not descend
directly from gpiobus and as such cannot make use of its features (one
classic example is gpioc that is attached to the GPIO controller and could
not, until now, make use of the gpiobus locking).

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Reintegrate head: r274132-r277384

Sponsored by: The FreeBSD Foundation

Reintegrate head revisions r273096-r277147

Sponsored by: The FreeBSD Foundation

MFhead @ r276594

Merge ^/head r274961 through r276301.

Improves the GPIO API description a little bit.

gpio_pin_max must return the maximum supported pin number and not the total
number of pins on the system.

PR: 157070
Submitted by: brix

Sync to HEAD@r274766

Merge from head@274682

Make gpio_default_map_gpios() static. No functional changes.

MFC @ r266724

An SVM update will follow this.

IFC @266473

Merge from head

Move gpiobus routines to dev/gpio. Avoid polluting ofw_bus with bus
specific parts.

Requested by: nwhitehorn

Merge svn+ssh://svn.freebsd.org/base/head@214309

Initial GPIO bus support. Includes:
- GPIO bus controller interface
- GPIO bus interface
- Implementation of GPIO led(4) compatible device
- Implementation of iic(4) bus over GPIO (author: Lu

Initial GPIO bus support. Includes:
- GPIO bus controller interface
- GPIO bus interface
- Implementation of GPIO led(4) compatible device
- Implementation of iic(4) bus over GPIO (author: Luiz Otavio O Souza)

Tested by: Luiz Otavio O Souza, Alexandr Rybalko

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