src-test/sys/dev/gpio, branch main

Provide userland notification of gpio pin changes ("userland gpio interrupts").

2020-12-12T18:34:15Z

This is an import of the Google Summer of Code 2018 project completed by Christian Kramer (and, sadly, ignored by us for two years now). The goals stated for that project were: FreeBSD already has support for interrupts implemented in the GPIO controller drivers of several SoCs, but there are no interfaces to take advantage of them out of user space yet. The goal of this work is to implement such an interface by providing descriptors which integrate with the common I/O system calls and multiplexing mechanisms. The initial imported code supports the following functionality: - A kernel driver that provides an interface to the user space; the existing gpioc(4) driver was enhanced with this functionality. - Implement support for the most common I/O system calls / multiplexing mechanisms: - read() Places the pin number on which the interrupt occurred in the buffer. Blocking and non-blocking behaviour supported. - poll()/select() - kqueue() - signal driven I/O. Posting SIGIO when the O_ASYNC was set. - Many-to-many relationship between pins and file descriptors. - A file descriptor can monitor several GPIO pins. - A GPIO pin can be monitored by multiple file descriptors. - Integration with gpioctl and libgpio. I added some fixes (mostly to locking) and feature enhancements on top of the original gsoc code. The feature ehancements allow the user to choose between detailed and summary event reporting. Detailed reporting provides a record describing each pin change event. Summary reporting provides the time of the first and last change of each pin, and a count of how many times it changed state since the last read(2) call. Another enhancement allows the recording of multiple state change events on multiple pins between each call to read(2) (the original code would track only a single event at a time). The phabricator review for these changes timed out without approval, but I cite it below anyway, because the review contains a series of diffs that show how I evolved the code from its original state in Christian's github repo for the gsoc project to what is being commited here. (In effect, the phab review extends the VC history back to the original code.) Submitted by: Christian Kramer Obtained from: https://github.com/ckraemer/freebsd/tree/gsoc2018 Differential Revision: https://reviews.freebsd.org/D27398

Allow for interrupts on pl061 children

2020-09-14T08:59:16Z

Add enough infrastructure for interrupts on children of the pl061 GPIO controller. As gpiobus already provided these the pl061 driver also needs to pass requests up the newbus hierarchy. Currently there are no children that expect to configure interrupts, however this is expected to change to support the ACPI Event Information interface. Sponsored by: Innovate UK

Move the pl061 acpi attachment earlier

2020-09-10T14:58:46Z

As the pl061 driver can be an interrupt controller attach it earlier in the boot so other drivers can use it. Use a new GPIO xref to not conflict with the existing root interrupt controller. Sponsored by: Innovate UK

Switch the name of the pl061 driver to gpio

2020-09-10T09:50:43Z

We need it to be named gpio for gpiobus to work. Sponsored by: Innovate UK

Only manage ofw gpio providers on ofw systems

2020-09-10T09:42:37Z

On arm64 we may boot via ACPI. In this case we will still try to manage the gpio providers as if we are using FDT. Fix this by checking if the FDT node is valid before registering a cross reference. Sponsored by: Innovate UK

Use the correct variable to check which interrupt mode to use

2020-09-10T09:37:30Z

In the PL061 driver we incorrectly used the mask rather than mode to find how to configure the interrupt. Sponsored by: Innovate UK

Add a GPIO driver for the Arm pl061 controller

2020-09-08T11:35:35Z

A PL061 is a simple 8 pin GPIO controller. This GPIO device is used to signal an internal request for shutdown on some virtual machines including Arm-based Amazon EC2 instances. Submitted by: Ali Saidi (previouss version) Reviewed by: Ali Saidi, manu Differential Revision: https://reviews.freebsd.org/D24065

gpiokeys: add evdev support

2020-08-12T09:49:25Z

Only linux,code is supported as it maps 1:1 to evdev key codes. No reverse mapping for freebsd,code yet. Reviewed by: wulf MFC after: 3 weeks Differential Revision: https://reviews.freebsd.org/D25940

gpioiic: never drive lines active high

2020-07-21T07:35:03Z

I2C communication is done by a combination of driving a line low or letting it float, so that it is either pulled up or driven low by another party. r355276 besides the stated goal of the change -- using the new GPIO API -- also changed the logic, so that active state is signaled by actively driving a line. That worked with iicbb prior to r362042, but stopped working after that commit on at least some hardware. My guess that the breakage was related to getting an ACK bit. A device expected to be able to drive SDA actively low, but controller was actively driving it high for some time. Anyway, this change seems to fix the problem. Tested using gpioiic on Orange Pi PC Plus with HTU21 sensor. Reported by: Nick Kostirya Reviewed by: manu MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D25684

gpiobus_release_pin: remove incorrect prefix from error messages

2020-06-22T10:32:41Z

It's interesting that similar messages from gpiobus_acquire_pin never had any prefix while gpiobus_release_pin messages were prefixed with "gpiobus_acquire_pin". Anyway, the prefix is not that useful and can be deduced from context. MFC after: 2 weeks