Here's the eleventh revision of the simulator.
As there was no reasoning with configfs maintainers for many months, this time the whole concept of committable items has been dropped. Instead, each configfs chip item (or rather a group - more on that later) exposes a new attribute called 'live'. Writing 1 to it brings the chip on-line (registers the platform device) and writing 0 tears it down.
There are some caveats to that approach - for example: we can't block the user-space from deleting chip items when chips are live but is just handled by silently destroying the chip device in the background.
In v11 the configfs structure has been deepened to allow creating multiple banks per platform device. The sysfs interface has changed so that the gpio_simX attributes are now under the bank's device node and not the platform device's.
v1 -> v2: - add selftests for gpio-sim - add helper programs for selftests - update the configfs rename callback to work with the new API introduced in v5.11 - fix a missing quote in the documentation - use !! whenever using bits operation that are required to return 0 or 1 - use provided bitmap API instead of reimplementing copy or fill operations - fix a deadlock in gpio_sim_direction_output() - add new read-only configfs attributes for mapping of configfs items to GPIO device names - and address other minor issues pointed out in reviews of v1
v2 -> v3: - use devm_bitmap_alloc() instead of the zalloc variant if we're initializing the bitmap with 1s - drop the patch exporting device_is_bound() - don't return -ENODEV from dev_nam and chip_name configfs attributes, return a string indicating that the device is not available yet ('n/a') - fix indentation where it makes sense - don't protect IDA functions which use their own locking and where it's not needed - use kmemdup() instead of kzalloc() + memcpy() - collected review tags - minor coding style fixes
v3 -> v4: - return 'none' instead of 'n/a' from dev_name and chip_name before the device is registered - use sysfs_emit() instead of s*printf() - drop GPIO_SIM_MAX_PROP as it's only used in an array's definition where it's fine to hardcode the value
v4 -> v5: - drop lib patches that are already upstream - use BIT() instead of (1UL << bit) for flags - fix refcounting for the configfs_dirent in rename() - drop d_move() from the rename() callback - free memory allocated for the live and pending groups in configfs_d_iput() and not in detach_groups() - make sure that if a group of some name is in the live directory, a new group with the same name cannot be created in the pending directory
v5 -> v6: - go back to using (1UL << bit) instead of BIT() - if the live group dentry doesn't exist for whatever reason at the time when mkdir() in the pending group is called (would be a BUG()), return -ENOENT instead of -EEXIST which should only be returned if given subsystem already exists in either live or pending group
v6 -> v7: - as detailed by Andy in commit 6fda593f3082 ("gpio: mockup: Convert to use software nodes") removing device properties after the platform device is removed but before the GPIO device gets dropped can lead to a use-after-free bug - use software nodes to manually control the freeing of the properties
v7 -> v8: - fixed some minor coding style issues as pointed out by Andy
v8 -> v9: - dropped the patches implementing committable-items and reworked the driver to not use them - reworked the gpio-line-names property and configuring specific lines in general - many smaller tweaks here and there
v9 -> v10: - make writing to 'live' wait for the probe to finish and report an error to user-space if it failed - add the ability to hog lines from the kernel-space - rework locking (drop separate locks for line context objects) - rework the sysfs interface (create a separate group for each line with a constant number of attributes instead of going the other way around)
v10 -> v11: - rework the configfs structure to represent a deeper hierarchy that gpiolib supports, namely: multiple banks per platform device
Bartosz Golaszewski (6): gpiolib: provide gpiod_remove_hogs() gpiolib: allow to specify the firmware node in struct gpio_chip gpio: sim: new testing module selftests: gpio: provide a helper for reading chip info selftests: gpio: add a helper for reading GPIO line names selftests: gpio: add test cases for gpio-sim
Documentation/admin-guide/gpio/gpio-sim.rst | 93 + drivers/gpio/Kconfig | 8 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-sim.c | 1592 +++++++++++++++++ drivers/gpio/gpiolib.c | 26 +- include/linux/gpio/driver.h | 2 + include/linux/gpio/machine.h | 2 + tools/testing/selftests/gpio/.gitignore | 2 + tools/testing/selftests/gpio/Makefile | 4 +- tools/testing/selftests/gpio/config | 1 + tools/testing/selftests/gpio/gpio-chip-info.c | 57 + tools/testing/selftests/gpio/gpio-line-name.c | 55 + tools/testing/selftests/gpio/gpio-sim.sh | 396 ++++ 13 files changed, 2236 insertions(+), 3 deletions(-) create mode 100644 Documentation/admin-guide/gpio/gpio-sim.rst create mode 100644 drivers/gpio/gpio-sim.c create mode 100644 tools/testing/selftests/gpio/gpio-chip-info.c create mode 100644 tools/testing/selftests/gpio/gpio-line-name.c create mode 100755 tools/testing/selftests/gpio/gpio-sim.sh