# Changelog
## v2.0.0-pre.6 - 2024-1-9
This release only has naming changes and documentation updates.
* Changes
* Rename `t:gpio_info/0` to `t:identifiers/0`, `t:gpio_status/0` to `t:status/0`
and `info/1` to `backend_info/1`. This hopefully removes confusion between
the 3 informational types and functions.
## v2.0.0-pre.5 - 2024-1-8
* Changes
* `t:gpio_info/0` now only contains static information so that it's easier to
cache. Caching reduces open time from 2-3ms to 100us on an RPi Zero, so it's
a decent improvement for apps that set a lot of GPIOs on boot.
* Add `t:status/0` and `status/1` to get runtime information about
GPIOs. It's currently populated with GPIO consumer info, direction and pull
mode. It could certainly have more added in the future.
* Add `write_one/3` and `read_one/2` convenience methods to simplify one-off
and IEx prompt usage. These open and close GPIO references behind the scenes
and reduce the code that you need to write to avoid exclusively holding on
to references.
* Make all error returns consistent. If an unknown errno is caught, its value
is returned so that a better error message can be added.
* Demote the `Circuits.GPIO.Info` struct to just a map so that backends can
add additional informational fields. The type to use is `t:gpio_info/0`.
* Various bug fixes and code cleanup
## v2.0.0-pre.4 - 2024-1-5
This release is looking really close to the final prerelease. Please provide
feedback soon if there are issues.
* Changes
* Add `Circuits.GPIO.gpio_spec?/1` and `Circuits.GPIO.is_gpio_spec/1` to
support sanity checking GPIOs when parsing config options in user code.
* Documentation updates
## v2.0.0-pre.3 - 2024-1-1
* Changes
* Add Circuits.GPIO.line_info/2 to simplify getting information about a GPIO
* Add consumer information to the line information and change the label to
just be the label rather than a tuple that contains the controller. This
matches better to what would normally be passed to `Circuits.GPIO.open/3`
* Add more information to the diagnostics report to simplify debugging
* Add a read performance measurement to the diagnostics report
## v2.0.0-pre.2 - 2023-12-30
* Changes
* Fix Beaglebone workaround issues
* Add Circuits.GPIO version to diagnostics and simplify
## v2.0.0-pre.1 - 2023-12-29
This is a major update over pre.0 that has a significant upgrade to the backend
for Nerves and Linux users.
* Changes
* Replace the Linux sysfs backend with one that uses the Linux cdev interface
* Add workaround for reordering of GPIO controllers on Beaglebones with Linux
5.15 and later.
* Add `Circuits.GPIO.Diagnostics` to simplify testing runtime capabilities
* Support pull modes on all targets that support them instead of only
Raspberry Pis
* Many documentation updates
## v2.0.0-pre.0 - 2023-05-30
This is a major update to Circuits.GPIO that removes the requirement to use
Nerves or Linux. The API is almost the same and the default is to compile and
use the Linux backend, so changes may not be needed.
This is a prerelease so APIs may still change before the v2.0.0 release.
* Changes
* Support alternative backends for different operating systems or for
simulated hardware
* Defer loading the Linux NIF until `Circuits.GPIO.open/2` is called
## v1.1.0 - 2022-12-31
* Changes
* Remove Erlang convenience functions since no one used them
* Require Elixir 1.10 or later. Previous versions probably work, but won't be
supported. This opens up the possibility of using Elixir 1.10+ features in
future releases.
## v1.0.1 - 2022-7-26
* Bug fixes
* On at least one device, the pin direction reported by Linux does not match
the actual pin direction. This release forces the pin direction for inputs.
It cannot do this for outputs, since setting a pin to output has a side
effect on the pin state. This technically is a bug in a Linux driver port,
but it was harmless to workaround for inputs so that's what's done. Thanks
to @pojiro for investigating and fixing this issue.
## v1.0.0 - 2021-10-20
This release only changes the version number. No code has changed.
## v0.4.8
This release only has doc and build output cleanup. No code has changed.
## v0.4.7
* Bug fixes
* Fix hang when unloading the NIF. This bug caused `:init.stop` to never
return and anything else that would try to unload this module.
* Fix C compiler warnings with OTP 24
The minimum Elixir version has been changed from 1.4 to 1.6. Elixir 1.4 might
still work, but it's no longer being verified on CI.
## v0.4.6
* Bug fixes
* Fix quoting issue that was causing failures on Yocto. Thanks to Zander
Erasmus for this.
## v0.4.5
* Bug fixes
* Opening a GPIO to read its state won't clear the interrupt status of another
listener. Registering for interrupts a second time will still clear out the
first registree, though. That's a limitation of the interface. However, for
debugging, it can be nice to look at a GPIO without affecting the program
and this change allows for that.
## v0.4.4
* Bug fixes
* Add -fPIC to compilation flags to fix build with `nerves_system_x86_64` and
other environments using the Musl C toolchains
## v0.4.3
* Bug fixes
* Fix GPIO glitch suppression when interrupts were enabled. Glitch suppression
filters out transitions on a GPIO line that are too fast for Linux and the
NIF to see both the rising and falling edges. Turning it off synthesizes
events. You can identify synthesized events since they have the same
timestamp to the nanosecond. See `Circuits.GPIO.set_interrupts/3`.
* Improvement
* It's possible to enable the "stub" on Linux by setting
`CIRCUITS_MIX_ENV=test`. This can be useful for unit testing code that uses
Circuits.GPIO. Thanks to Enrico Rivarola for adding this!
## v0.4.2
* Bug fixes
* Fix pullup/pulldown support for the Raspberry Pi 4
## v0.4.1
* Bug fixes
* Fix a race condition on Raspbian where Circuits.GPIO would try to open the
GPIO sysfs file before udev had a chance to fix its permissions.
* Fix RPi platform detection on Raspbian so that pull-ups/pull-downs work
without passing any flags.
## v0.4.0
The GPIO interrupt notification messages have been changed for consistency with
other circuits projects. The initial element of the tuple is now
`:circuits_gpio`, so messages will look like:
`{:circuits_gpio, 19, 83268239, 1}`
Please update your project if you call `set_interrupts/2`.
No more backwards incompatible changes are expected until after 1.0.
## v0.3.1
* Bug fixes
* Build C source under the `_build` directory so that changing targets
properly rebuilds the C code as well as the Elixir.
## v0.3.0
* New features
* Support `pull_mode` initializion in `open/3`.
## v0.2.0
* New features
* Add support for opening GPIOs to an initial value or to not change the
value. This removes a glitch if you want the GPIO to start out high (the
default was low) or if you want the GPIO to keep its current value.
## v0.1.0
Initial release to hex.
