Merge tag 'gpio-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski:
 "The majority of added lines are two new modules: the GPIO virtual
  consumer module that improves our ability to add automated tests for
  the kernel API and the "sloppy" logic analyzer module that uses the
  GPIO API to implement a coarse-grained debugging tool for useful for
  remote development.

  Other than that we have the usual assortment of various driver
  extensions, improvements to the core GPIO code, DT-bindings and other
  documentation updates as well as an extension to the interrupt
  simulator:

  GPIOLIB core:
   - rework kfifo handling rework in the character device code
   - improve the labeling of GPIOs requested as interrupts and show more
     info on interrupt-only GPIOs in debugfs
   - remove unused APIs
   - unexport interfaces that are only used from the core GPIO code
   - drop the return value from gpiochip_set_desc_names() as it cannot
     fail
   - move a string array definition out of a header and into a specific
     compilation unit
   - convert the last user of gpiochip_get_desc() other than GPIO core
     to using a safer alternative
   - use array_index_nospec() where applicable

  New drivers:
   - add a "virtual GPIO consumer" module that allows requesting GPIOs
     from actual hardware and driving tests of the in-kernel GPIO API
     from user-space over debugfs
   - add a GPIO-based "sloppy" logic analyzer module useful for "first
     glance" debugging on remote boards

  Driver improvements:
   - add support for a new model to gpio-pca953x
   - lock GPIOs as interrupts in gpio-sim when the lines are requested
     as irqs via the simulator domain + some other minor improvements
   - improve error reporting in gpio-syscon
   - convert gpio-ath79 to using dynamic GPIO base and range
   - use pcibios_err_to_errno() for converting PCIBIOS error codes to
     errno vaues in gpio-amd8111 and gpio-rdc321x
   - allow building gpio-brcmstb for the BCM2835 architecture

  DT bindings:
   - convert DT bindings for lsi,zevio, mpc8xxx, and atmel to DT schema
   - document new properties for aspeed,gpio, fsl,qoriq-gpio and
     gpio-vf610
   - document new compatibles for pca953x and fsl,qoriq-gpio

  Documentation:
   - document stricter behavior of the GPIO character device uAPI with
     regards to reconfiguring requested line without direction set
   - clarify the effect of the active-low flag on line values and edges
   - remove documentation for the legacy GPIO API in order to stop
     tempting people to use it
   - document the preference for using pread() for reading edge events
     in the sysfs API

  Other:
   - add an extended initializer to the interrupt simulator allowing to
     specify a number of callbacks callers can use to be notified about
     irqs being requested and released"

* tag 'gpio-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (41 commits)
  gpio: mc33880: Convert comma to semicolon
  gpio: virtuser: actually use the "trimmed" local variable
  dt-bindings: gpio: convert Atmel GPIO to json-schema
  gpio: virtuser: new virtual testing driver for the GPIO API
  dt-bindings: gpio: vf610: Allow gpio-line-names to be set
  gpio: sim: lock GPIOs as interrupts when they are requested
  genirq/irq_sim: add an extended irq_sim initializer
  dt-bindings: gpio: fsl,qoriq-gpio: Add compatible string fsl,ls1046a-gpio
  gpiolib: unexport gpiochip_get_desc()
  gpio: add sloppy logic analyzer using polling
  Documentation: gpio: Reconfiguration with unset direction (uAPI v2)
  Documentation: gpio: Reconfiguration with unset direction (uAPI v1)
  dt-bindings: gpio: fsl,qoriq-gpio: add common property gpio-line-names
  gpio: ath79: convert to dynamic GPIO base allocation
  pinctrl: da9062: replace gpiochip_get_desc() with gpio_device_get_desc()
  gpiolib: put gpio_suffixes in a single compilation unit
  Documentation: gpio: Clarify effect of active low flag on line edges
  Documentation: gpio: Clarify effect of active low flag on line values
  gpiolib: Remove data-less gpiochip_add() function
  gpio: sim: use devm_mutex_init()
  ...

1 files changed, 177 insertions, 0 deletions

diff --git a/Documentation/admin-guide/gpio/gpio-virtuser.rst b/Documentation/admin-guide/gpio/gpio-virtuser.rst
new file mode 100644
index 000000000000..2aca70db9f3b
--- /dev/null
+++ b/Documentation/admin-guide/gpio/gpio-virtuser.rst
@@ -0,0 +1,177 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Virtual GPIO Consumer
+=====================
+
+The virtual GPIO Consumer module allows users to instantiate virtual devices
+that request GPIOs and then control their behavior over debugfs. Virtual
+consumer devices can be instantiated from device-tree or over configfs.
+
+A virtual consumer uses the driver-facing GPIO APIs and allows to cover it with
+automated tests driven by user-space. The GPIOs are requested using
+``gpiod_get_array()`` and so we support multiple GPIOs per connector ID.
+
+Creating GPIO consumers
+-----------------------
+
+The gpio-consumer module registers a configfs subsystem called
+``'gpio-virtuser'``. For details of the configfs filesystem, please refer to
+the configfs documentation.
+
+The user can create a hierarchy of configfs groups and items as well as modify
+values of exposed attributes. Once the consumer is instantiated, this hierarchy
+will be translated to appropriate device properties. The general structure is:
+
+**Group:** ``/config/gpio-virtuser``
+
+This is the top directory of the gpio-consumer configfs tree.
+
+**Group:** ``/config/gpio-consumer/example-name``
+
+**Attribute:** ``/config/gpio-consumer/example-name/live``
+
+**Attribute:** ``/config/gpio-consumer/example-name/dev_name``
+
+This is a directory representing a GPIO consumer device.
+
+The read-only ``dev_name`` attribute exposes the name of the device as it will
+appear in the system on the platform bus. This is useful for locating the
+associated debugfs directory under
+``/sys/kernel/debug/gpio-virtuser/$dev_name``.
+
+The ``'live'`` attribute allows to trigger the actual creation of the device
+once it's fully configured. The accepted values are: ``'1'`` to enable the
+virtual device and ``'0'`` to disable and tear it down.
+
+Creating GPIO lookup tables
+---------------------------
+
+Users can create a number of configfs groups under the device group:
+
+**Group:** ``/config/gpio-consumer/example-name/con_id``
+
+The ``'con_id'`` directory represents a single GPIO lookup and its value maps
+to the ``'con_id'`` argument of the ``gpiod_get()`` function. For example:
+``con_id`` == ``'reset'`` maps to the ``reset-gpios`` device property.
+
+Users can assign a number of GPIOs to each lookup. Each GPIO is a sub-directory
+with a user-defined name under the ``'con_id'`` group.
+
+**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/key``
+
+**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/offset``
+
+**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/drive``
+
+**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/pull``
+
+**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/active_low``
+
+**Attribute:** ``/config/gpio-consumer/example-name/con_id/0/transitory``
+
+This is a group describing a single GPIO in the ``con_id-gpios`` property.
+
+For virtual consumers created using configfs we use machine lookup tables so
+this group can be considered as a mapping between the filesystem and the fields
+of a single entry in ``'struct gpiod_lookup'``.
+
+The ``'key'`` attribute represents either the name of the chip this GPIO
+belongs to or the GPIO line name. This depends on the value of the ``'offset'``
+attribute: if its value is >= 0, then ``'key'`` represents the label of the
+chip to lookup while ``'offset'`` represents the offset of the line in that
+chip. If ``'offset'`` is < 0, then ``'key'`` represents the name of the line.
+
+The remaining attributes map to the ``'flags'`` field of the GPIO lookup
+struct. The first two take string values as arguments:
+
+**``'drive'``:** ``'push-pull'``, ``'open-drain'``, ``'open-source'``
+**``'pull'``:** ``'pull-up'``, ``'pull-down'``, ``'pull-disabled'``, ``'as-is'``
+
+``'active_low'`` and ``'transitory'`` are boolean attributes.
+
+Activating GPIO consumers
+-------------------------
+
+Once the confiuration is complete, the ``'live'`` attribute must be set to 1 in
+order to instantiate the consumer. It can be set back to 0 to destroy the
+virtual device. The module will synchronously wait for the new simulated device
+to be successfully probed and if this doesn't happen, writing to ``'live'`` will
+result in an error.
+
+Device-tree
+-----------
+
+Virtual GPIO consumers can also be defined in device-tree. The compatible string
+must be: ``"gpio-virtuser"`` with at least one property following the
+standardized GPIO pattern.
+
+An example device-tree code defining a virtual GPIO consumer:
+
+.. code-block :: none
+
+    gpio-virt-consumer {
+        compatible = "gpio-virtuser";
+
+        foo-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>, <&gpio1 2 0>;
+        bar-gpios = <&gpio0 6 0>;
+    };
+
+Controlling virtual GPIO consumers
+----------------------------------
+
+Once active, the device will export debugfs attributes for controlling GPIO
+arrays as well as each requested GPIO line separately. Let's consider the
+following device property: ``foo-gpios = <&gpio0 0 0>, <&gpio0 4 0>;``.
+
+The following debugfs attribute groups will be created:
+
+**Group:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo/``
+
+This is the group that will contain the attributes for the entire GPIO array.
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo/values``
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo/values_atomic``
+
+Both attributes allow to read and set arrays of GPIO values. User must pass
+exactly the number of values that the array contains in the form of a string
+containing zeroes and ones representing inactive and active GPIO states
+respectively. In this example: ``echo 11 > values``.
+
+The ``values_atomic`` attribute works the same as ``values`` but the kernel
+will execute the GPIO driver callbacks in interrupt context.
+
+**Group:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/``
+
+This is a group that represents a single GPIO with ``$index`` being its offset
+in the array.
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/consumer``
+
+Allows to set and read the consumer label of the GPIO line.
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/debounce``
+
+Allows to set and read the debounce period of the GPIO line.
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/direction``
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/direction_atomic``
+
+These two attributes allow to set the direction of the GPIO line. They accept
+"input" and "output" as values. The atomic variant executes the driver callback
+in interrupt context.
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/interrupts``
+
+If the line is requested in input mode, writing ``1`` to this attribute will
+make the module listen for edge interrupts on the GPIO. Writing ``0`` disables
+the monitoring. Reading this attribute returns the current number of registered
+interrupts (both edges).
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/value``
+
+**Attribute:** ``/sys/kernel/debug/gpio-virtuser/$dev_name/gpiod:foo:$index/value_atomic``
+
+Both attributes allow to read and set values of individual requested GPIO lines.
+They accept the following values: ``1`` and ``0``.