A driver for the NXP SC16IS7xx family of UART chips. This family is
mostly a 16C450 with features from the 16C550, 16C650 and 16C750 and
makes use of src/sys/dev/ic/com.c for much of the heavy lifting.

A BIG difference is that the chip family is attached via a I2C or SPI
bus and is in no way, shape or form, attached to the computer via a
computer bus.

Since spin locks are not allowed to be held while calling to the I2C
or SPI framework com.c grew a new hw feature flag where it could be
run at something other than a hard IP level and doesn't hold spin lock
(for very long). In particular, IPL_SOFTSERIAL. This method is
enabled via a hw feature flag and should not effect any other use of
com.c. Other changes with this new method of use include the use of
workqueues and such.

A further feature added to com.c was the abilty to take advantage of
the MCR prescaler that is present in the SC16IS7xx family and likely
present in the 16C650. This prescaler is tried if the baud rate
requested can not be met with the frequency oscillator that the chip is
built with.

The chip family does not use any particular frequency oscillator for
the baud rate generator. In order to deal with this the frequency can
be set via sysctl, a kernel option or with a FDT overlay if that is
supported.

Most of the features of the chip family are supported including the
gpio pins via gpiobus(4) that are present with some of the family
members.

The chip can attach via I2C or SPI and can make sure of FDT if that is
present in the system.

This chip family has been around for quite some time and there are a
number of breakout boards on Amazon. It is also reasonably priced and
you can roll your own board if you can perform simple SMD soldering as
very few additional components are required.

Mention umcpmio(4)

branches: 1.37.4;
s/unaccessible/inaccessible/

Fix incorrect structure name (Rocky Hotas)

grammar

expand section on GPIOREAD

branches: 1.33.2;
Overhaul of GPIO interrupt support (that wasn't even used by anything).
- Remove the old, not-expressive-enough interrupt flags, and replace them
with a new set of interrupt-specific flags that can express a wide
variety of interrupt configurations (pos, neg, and double-edge, high
and low level).
- Remove old, unused gpio_pin_ctl_intr() and gpio_pin_irqen(), and
replace them with gpio_intr_establish(), gpio_intr_disestablish(),
and gpio_intr_str(). Corresponding fields in the gpio_chipset_tag
are also added for back-end controllers, which now handle the actual
dispatch of GPIO interrupts in order to properly support level-triggered
interrupts as well as interoperate properly with FDT-registered
interrupts.

Piggy-back on the 8.99.18 version bump.

Inspired by initial work from Brad Spencer.
PR kern/51676

branches: 1.32.2;
Whitespace improvements. Remove unnecessary Tn.

Update to include wbsio as a possible parent for a gpio device.

XXX Should we really list all the possible parents? Or should we replace
XXX this entire list with a single entry for "gpio* at gpiobus?"

Bump date for previous.

document new pin configuration flags

Merge riastradh-drm2 to HEAD.

Use Mt for email addresses.

branches: 1.26.2;
Bump date for previous.

adjust soekrisgpio driver to NetBSD

Mention ptcd(4) in the synopsis.

branches: 1.23.2; 1.23.6;
Bring up to reality.

branches: 1.22.2;
Sort SEE ALSO.

Remove the GPIODETACH gpio(4) ioctl (it is still available in COMPAT_50) and
the 'detach' command line option from gpioctl(8). Drivers that are
attached to gpio pins can be detached using the drvctl(8) command.

Add a ga_flags field to the gpio_attach structure to hand driver
specific flags to drivers being attached at gpio pins. gpioiic(4)
uses this to reverse the SDA/SCL signal order. gpioctl(8) accepts
the flag values as optional argument to the attach command.
While here, make sure we retain backwards compatability and wrap compat
code in #ifdef COMPAT_50/#endif.

Add a new ioctl, GPIOPULSE to gpio(4) to allow for pulsing a pin.
If a pin can pulse in hardware, that will be used, else it will
be pulsed in software. There is no way yet to set the pulse frequency
for pins that pulse in hardware. While here, make the code mpsafe and
allow more than one thread in the driver (access to ioctl is serialized).

branches: 1.18.2;
Use .In instead of .Aq Pa for header files.

Bump date for today's changes.

gpio(4) support for Intel ICH southbridges.

Tested on Intel SS4200-E (ICH7), and Acorp 6A815EPD (ICH2) motherboards,
on amd64 and i386 ports respectively.

It should be noted that the majority of boards with ICH chips do not
expose the GPIO pins for off-board use. For instance, aside from the
three exposed-on-a-header pins on the 6A815EPD, another pin is also
used to control write protect on the FWH. The SS4200 exposes the GPIO
on a header that connects to the 10 LEDs on the front panel, as well
as a tact switch on the back panel.

Jonatha Kollasch has a GPIO device that can pulse the output lines.
Support it wuth the GPIO_PIN_PULSE attribute and the 'pulse' paramater
to gpioctl. Discussed with Jonathan.

Reword slightly so I can understand it more easily.

Mention that defining the GPIO layout is subject to kauth(9) auhtorization.
Suggested by Elad Efrat.

Sprinkle a few .Pps.

Sort SYNOPSIS, add gpio* at gpiosim?.

Reword for better HTML output.

Document recent gpio(4) changes and introduce a new config file for GPIO.
Integrate with the startup scripts in /etc/rc.d. Introduce new variable
"gpio" for /etc/rc.conf.

Improved support for GPIO support on the EP93xx ARM processors.
Specifically:

Support disabling specific pins on specific ports.
Modification of TS7200 kernel config file for GPIO support.
Documentatin for the current and improved GPIO interface (epgpio).

branches: 1.7.4; 1.7.6;
gpio(4): Extend with open/close to request/release the ppbus(4) on open/close.
ppbus(4): Extend to attach on gpiobus.
From Hans Rosenfeld from tech-kern:
http://mail-index.netbsd.org/tech-kern/2008/04/28/msg001168.html
Hint: Hans sent me this diff which differs in the one from tech-kern in:
- 2-clause license
- sprinkled some consts

branches: 1.6.4; 1.6.6;
Mention GPIO_PIN_PULLDOWN, GPIO_PIN_INVIN and GPIO_PIN_INVOUT; from OpenBSD.

<wizd> bump date!

Mention gcscpcib(4), reorder entries, just mention gpioctl(8) and
not all drivers again.

branches: 1.3.12;
Note that gpio can attach to elansc, and xref elansc(4). Bump date.

Use .In. Mention NetBSD import. Use .Nx.

Add man page for gpio framework (from OpenBSD)

A driver for the NXP SC16IS7xx family of UART chips. This family is
mostly a 16C450 with features from the 16C550, 16C650 and 16C750 and
makes use of src/sys/dev/ic/com.c for much of the heavy lifting.

A BIG difference is that the chip family is attached via a I2C or SPI
bus and is in no way, shape or form, attached to the computer via a
computer bus.

Since spin locks are not allowed to be held while calling to the I2C
or SPI framework com.c grew a new hw feature flag where it could be
run at something other than a hard IP level and doesn't hold spin lock
(for very long). In particular, IPL_SOFTSERIAL. This method is
enabled via a hw feature flag and should not effect any other use of
com.c. Other changes with this new method of use include the use of
workqueues and such.

A further feature added to com.c was the abilty to take advantage of
the MCR prescaler that is present in the SC16IS7xx family and likely
present in the 16C650. This prescaler is tried if the baud rate
requested can not be met with the frequency oscillator that the chip is
built with.

The chip family does not use any particular frequency oscillator for
the baud rate generator. In order to deal with this the frequency can
be set via sysctl, a kernel option or with a FDT overlay if that is
supported.

Most of the features of the chip family are supported including the
gpio pins via gpiobus(4) that are present with some of the family
members.

The chip can attach via I2C or SPI and can make sure of FDT if that is
present in the system.

This chip family has been around for quite some time and there are a
number of breakout boards on Amazon. It is also reasonably priced and
you can roll your own board if you can perform simple SMD soldering as
very few additional components are required.

Mention umcpmio(4)

branches: 1.37.4;
s/unaccessible/inaccessible/

Fix incorrect structure name (Rocky Hotas)

grammar

expand section on GPIOREAD

branches: 1.33.2;
Overhaul of GPIO interrupt support (that wasn't even used by anything).
- Remove the old, not-expressive-enough interrupt flags, and replace them
with a new set of interrupt-specific flags that can express a wide
variety of interrupt configurations (pos, neg, and double-edge, high
and low level).
- Remove old, unused gpio_pin_ctl_intr() and gpio_pin_irqen(), and
replace them with gpio_intr_establish(), gpio_intr_disestablish(),
and gpio_intr_str(). Corresponding fields in the gpio_chipset_tag
are also added for back-end controllers, which now handle the actual
dispatch of GPIO interrupts in order to properly support level-triggered
interrupts as well as interoperate properly with FDT-registered
interrupts.

Piggy-back on the 8.99.18 version bump.

Inspired by initial work from Brad Spencer.
PR kern/51676

branches: 1.32.2;
Whitespace improvements. Remove unnecessary Tn.

Update to include wbsio as a possible parent for a gpio device.

XXX Should we really list all the possible parents? Or should we replace
XXX this entire list with a single entry for "gpio* at gpiobus?"

Bump date for previous.

document new pin configuration flags

Merge riastradh-drm2 to HEAD.

Use Mt for email addresses.

branches: 1.26.2;
Bump date for previous.

adjust soekrisgpio driver to NetBSD

Mention ptcd(4) in the synopsis.

branches: 1.23.2; 1.23.6;
Bring up to reality.

branches: 1.22.2;
Sort SEE ALSO.

Remove the GPIODETACH gpio(4) ioctl (it is still available in COMPAT_50) and
the 'detach' command line option from gpioctl(8). Drivers that are
attached to gpio pins can be detached using the drvctl(8) command.

Add a ga_flags field to the gpio_attach structure to hand driver
specific flags to drivers being attached at gpio pins. gpioiic(4)
uses this to reverse the SDA/SCL signal order. gpioctl(8) accepts
the flag values as optional argument to the attach command.
While here, make sure we retain backwards compatability and wrap compat
code in #ifdef COMPAT_50/#endif.

Add a new ioctl, GPIOPULSE to gpio(4) to allow for pulsing a pin.
If a pin can pulse in hardware, that will be used, else it will
be pulsed in software. There is no way yet to set the pulse frequency
for pins that pulse in hardware. While here, make the code mpsafe and
allow more than one thread in the driver (access to ioctl is serialized).

branches: 1.18.2;
Use .In instead of .Aq Pa for header files.

Bump date for today's changes.

gpio(4) support for Intel ICH southbridges.

Tested on Intel SS4200-E (ICH7), and Acorp 6A815EPD (ICH2) motherboards,
on amd64 and i386 ports respectively.

It should be noted that the majority of boards with ICH chips do not
expose the GPIO pins for off-board use. For instance, aside from the
three exposed-on-a-header pins on the 6A815EPD, another pin is also
used to control write protect on the FWH. The SS4200 exposes the GPIO
on a header that connects to the 10 LEDs on the front panel, as well
as a tact switch on the back panel.

Jonatha Kollasch has a GPIO device that can pulse the output lines.
Support it wuth the GPIO_PIN_PULSE attribute and the 'pulse' paramater
to gpioctl. Discussed with Jonathan.

Reword slightly so I can understand it more easily.

Mention that defining the GPIO layout is subject to kauth(9) auhtorization.
Suggested by Elad Efrat.

Sprinkle a few .Pps.

Sort SYNOPSIS, add gpio* at gpiosim?.

Reword for better HTML output.

Document recent gpio(4) changes and introduce a new config file for GPIO.
Integrate with the startup scripts in /etc/rc.d. Introduce new variable
"gpio" for /etc/rc.conf.

Improved support for GPIO support on the EP93xx ARM processors.
Specifically:

Support disabling specific pins on specific ports.
Modification of TS7200 kernel config file for GPIO support.
Documentatin for the current and improved GPIO interface (epgpio).

branches: 1.7.4; 1.7.6;
gpio(4): Extend with open/close to request/release the ppbus(4) on open/close.
ppbus(4): Extend to attach on gpiobus.
From Hans Rosenfeld from tech-kern:
http://mail-index.netbsd.org/tech-kern/2008/04/28/msg001168.html
Hint: Hans sent me this diff which differs in the one from tech-kern in:
- 2-clause license
- sprinkled some consts

branches: 1.6.4; 1.6.6;
Mention GPIO_PIN_PULLDOWN, GPIO_PIN_INVIN and GPIO_PIN_INVOUT; from OpenBSD.

<wizd> bump date!

Mention gcscpcib(4), reorder entries, just mention gpioctl(8) and
not all drivers again.

branches: 1.3.12;
Note that gpio can attach to elansc, and xref elansc(4). Bump date.

Use .In. Mention NetBSD import. Use .Nx.

Add man page for gpio framework (from OpenBSD)