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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-30 11:15:39 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-30 11:15:39 -0700 |
commit | 776ba3ad659e4955079f57f8d859e7994ea35076 (patch) | |
tree | 18b27ed3684dfbe1c1ee2d4b54706657c551b346 /Documentation/driver-api/surface_aggregator | |
parent | ebb81c14543fb43cb2e1f2bfb5d32f5e390cf895 (diff) | |
parent | 0e695c3f7f66c66e0a1da90cc5378198a656d494 (diff) | |
download | linux-776ba3ad659e4955079f57f8d859e7994ea35076.tar.bz2 |
Merge tag 'platform-drivers-x86-v5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
Pull x86 platform driver updates from Hans de Goede:
"Highlights:
- New think-lmi driver adding support for changing Lenovo Thinkpad
BIOS settings from within Linux using the standard firmware-
attributes class sysfs API
- MS Surface aggregator-cdev now also supports forwarding events to
user-space (for debugging / new driver development purposes only)
- New intel_skl_int3472 driver this provides the necessary glue to
translate ACPI table information to GPIOs, regulators, etc. for
camera sensors on Intel devices with IPU3 attached MIPI cameras
- A whole bunch of other fixes + device-specific quirk additions
- New devm_work_autocancel() devm-helpers.h function"
* tag 'platform-drivers-x86-v5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (83 commits)
platform/x86: dell-wmi-sysman: Change user experience when Admin/System Password is modified
platform/x86: intel_skl_int3472: Uninitialized variable in skl_int3472_handle_gpio_resources()
platform/x86: think-lmi: Move kfree(setting->possible_values) to tlmi_attr_setting_release()
platform/x86: think-lmi: Split current_value to reflect only the value
platform/x86: think-lmi: Fix issues with duplicate attributes
platform/x86: think-lmi: Return EINVAL when kbdlang gets set to a 0 length string
platform/x86: intel_cht_int33fe: Move to its own subfolder
platform/x86: intel_skl_int3472: Move to intel/ subfolder
platform/x86: intel_skl_int3472: Provide skl_int3472_unregister_clock()
platform/x86: intel_skl_int3472: Provide skl_int3472_unregister_regulator()
platform/x86: intel_skl_int3472: Use ACPI GPIO resource directly
platform/x86: intel_skl_int3472: Fix dependencies (drop CLKDEV_LOOKUP)
platform/x86: intel_skl_int3472: Free ACPI device resources after use
platform/x86: Remove "default n" entries
platform/x86: ISST: Use numa node id for cpu pci dev mapping
platform/x86: ISST: Optimize CPU to PCI device mapping
tools/power/x86/intel-speed-select: v1.10 release
tools/power/x86/intel-speed-select: Fix uncore memory frequency display
extcon: extcon-max8997: Simplify driver using devm
extcon: extcon-max8997: Fix IRQ freeing at error path
...
Diffstat (limited to 'Documentation/driver-api/surface_aggregator')
-rw-r--r-- | Documentation/driver-api/surface_aggregator/clients/cdev.rst | 127 |
1 files changed, 122 insertions, 5 deletions
diff --git a/Documentation/driver-api/surface_aggregator/clients/cdev.rst b/Documentation/driver-api/surface_aggregator/clients/cdev.rst index 248c1372d879..0134a841a079 100644 --- a/Documentation/driver-api/surface_aggregator/clients/cdev.rst +++ b/Documentation/driver-api/surface_aggregator/clients/cdev.rst @@ -1,9 +1,8 @@ .. SPDX-License-Identifier: GPL-2.0+ -.. |u8| replace:: :c:type:`u8 <u8>` -.. |u16| replace:: :c:type:`u16 <u16>` .. |ssam_cdev_request| replace:: :c:type:`struct ssam_cdev_request <ssam_cdev_request>` .. |ssam_cdev_request_flags| replace:: :c:type:`enum ssam_cdev_request_flags <ssam_cdev_request_flags>` +.. |ssam_cdev_event| replace:: :c:type:`struct ssam_cdev_event <ssam_cdev_event>` ============================== User-Space EC Interface (cdev) @@ -23,6 +22,40 @@ These IOCTLs and their respective input/output parameter structs are defined in A small python library and scripts for accessing this interface can be found at https://github.com/linux-surface/surface-aggregator-module/tree/master/scripts/ssam. +.. contents:: + + +Receiving Events +================ + +Events can be received by reading from the device-file. The are represented by +the |ssam_cdev_event| datatype. + +Before events are available to be read, however, the desired notifiers must be +registered via the ``SSAM_CDEV_NOTIF_REGISTER`` IOCTL. Notifiers are, in +essence, callbacks, called when the EC sends an event. They are, in this +interface, associated with a specific target category and device-file-instance. +They forward any event of this category to the buffer of the corresponding +instance, from which it can then be read. + +Notifiers themselves do not enable events on the EC. Thus, it may additionally +be necessary to enable events via the ``SSAM_CDEV_EVENT_ENABLE`` IOCTL. While +notifiers work per-client (i.e. per-device-file-instance), events are enabled +globally, for the EC and all of its clients (regardless of userspace or +non-userspace). The ``SSAM_CDEV_EVENT_ENABLE`` and ``SSAM_CDEV_EVENT_DISABLE`` +IOCTLs take care of reference counting the events, such that an event is +enabled as long as there is a client that has requested it. + +Note that enabled events are not automatically disabled once the client +instance is closed. Therefore any client process (or group of processes) should +balance their event enable calls with the corresponding event disable calls. It +is, however, perfectly valid to enable and disable events on different client +instances. For example, it is valid to set up notifiers and read events on +client instance ``A``, enable those events on instance ``B`` (note that these +will also be received by A since events are enabled/disabled globally), and +after no more events are desired, disable the previously enabled events via +instance ``C``. + Controller IOCTLs ================= @@ -45,9 +78,33 @@ The following IOCTLs are provided: - ``REQUEST`` - Perform synchronous SAM request. + * - ``0xA5`` + - ``2`` + - ``W`` + - ``NOTIF_REGISTER`` + - Register event notifier. -``REQUEST`` ------------ + * - ``0xA5`` + - ``3`` + - ``W`` + - ``NOTIF_UNREGISTER`` + - Unregister event notifier. + + * - ``0xA5`` + - ``4`` + - ``W`` + - ``EVENT_ENABLE`` + - Enable event source. + + * - ``0xA5`` + - ``5`` + - ``W`` + - ``EVENT_DISABLE`` + - Disable event source. + + +``SSAM_CDEV_REQUEST`` +--------------------- Defined as ``_IOWR(0xA5, 1, struct ssam_cdev_request)``. @@ -82,6 +139,66 @@ submitted, and completed (i.e. handed back to user-space) successfully from inside the IOCTL, but the request ``status`` member may still be negative in case the actual execution of the request failed after it has been submitted. -A full definition of the argument struct is provided below: +A full definition of the argument struct is provided below. + +``SSAM_CDEV_NOTIF_REGISTER`` +---------------------------- + +Defined as ``_IOW(0xA5, 2, struct ssam_cdev_notifier_desc)``. + +Register a notifier for the event target category specified in the given +notifier description with the specified priority. Notifiers registration is +required to receive events, but does not enable events themselves. After a +notifier for a specific target category has been registered, all events of that +category will be forwarded to the userspace client and can then be read from +the device file instance. Note that events may have to be enabled, e.g. via the +``SSAM_CDEV_EVENT_ENABLE`` IOCTL, before the EC will send them. + +Only one notifier can be registered per target category and client instance. If +a notifier has already been registered, this IOCTL will fail with ``-EEXIST``. + +Notifiers will automatically be removed when the device file instance is +closed. + +``SSAM_CDEV_NOTIF_UNREGISTER`` +------------------------------ + +Defined as ``_IOW(0xA5, 3, struct ssam_cdev_notifier_desc)``. + +Unregisters the notifier associated with the specified target category. The +priority field will be ignored by this IOCTL. If no notifier has been +registered for this client instance and the given category, this IOCTL will +fail with ``-ENOENT``. + +``SSAM_CDEV_EVENT_ENABLE`` +-------------------------- + +Defined as ``_IOW(0xA5, 4, struct ssam_cdev_event_desc)``. + +Enable the event associated with the given event descriptor. + +Note that this call will not register a notifier itself, it will only enable +events on the controller. If you want to receive events by reading from the +device file, you will need to register the corresponding notifier(s) on that +instance. + +Events are not automatically disabled when the device file is closed. This must +be done manually, via a call to the ``SSAM_CDEV_EVENT_DISABLE`` IOCTL. + +``SSAM_CDEV_EVENT_DISABLE`` +--------------------------- + +Defined as ``_IOW(0xA5, 5, struct ssam_cdev_event_desc)``. + +Disable the event associated with the given event descriptor. + +Note that this will not unregister any notifiers. Events may still be received +and forwarded to user-space after this call. The only safe way of stopping +events from being received is unregistering all previously registered +notifiers. + + +Structures and Enums +==================== .. kernel-doc:: include/uapi/linux/surface_aggregator/cdev.h |