| Message ID | 20250407043019.4105613-1-koichiro.den@canonical.com |
|---|---|
| Headers | show |
| Series | Introduce configfs-based interface for gpio-aggregator | expand |
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> On Mon, 07 Apr 2025 13:30:10 +0900, Koichiro Den wrote: > This patch series introduces a configfs-based interface to gpio-aggregator > to address limitations in the existing 'new_device' interface. > > The existing 'new_device' interface has several limitations: > > Issue#1. No way to determine when GPIO aggregator creation is complete. > Issue#2. No way to retrieve errors when creating a GPIO aggregator. > Issue#3. No way to trace a GPIO line of an aggregator back to its > corresponding physical device. > Issue#4. The 'new_device' echo does not indicate which virtual > gpiochip<N> was created. > Issue#5. No way to assign names to GPIO lines exported through an > aggregator. > > [...] Applied, thanks! [1/9] gpio: aggregator: reorder functions to prepare for configfs introduction https://git.kernel.org/brgl/linux/c/7a56efeabffd13a162073068b8e29113c65f9e64 [2/9] gpio: aggregator: unify function naming https://git.kernel.org/brgl/linux/c/7616dd97ae22e5f69b24774455673d183d4191c9 [3/9] gpio: aggregator: add gpio_aggregator_{alloc,free}() https://git.kernel.org/brgl/linux/c/88fe1d1a646b3b01dcc335c44e7b33ea510f620e [4/9] gpio: aggregator: introduce basic configfs interface https://git.kernel.org/brgl/linux/c/2b72a5399eae25ee2cfd447efa3012f1d9d7257d [5/9] gpio: aggregator: rename 'name' to 'key' in gpio_aggregator_parse() https://git.kernel.org/brgl/linux/c/26ec717c3b160d00a91e647c8ecfa33eaf645b05 [6/9] gpio: aggregator: expose aggregator created via legacy sysfs to configfs https://git.kernel.org/brgl/linux/c/09708f2b1cee33d585606932fb0ff5bb4c49f48d [7/9] gpio: aggregator: cancel deferred probe for devices created via configfs https://git.kernel.org/brgl/linux/c/62cf750f23a8905be5cf4471087068c1fe2e2d5b [8/9] Documentation: gpio: document configfs interface for gpio-aggregator https://git.kernel.org/brgl/linux/c/017ae62c1d0bb4b3c29c8a15dc7c130e3c4783b8 [9/9] selftests: gpio: add test cases for gpio-aggregator https://git.kernel.org/brgl/linux/c/93ada5ce07889271aefb22147280cfd9cf3da5d8 Best regards,
This patch series introduces a configfs-based interface to gpio-aggregator to address limitations in the existing 'new_device' interface. The existing 'new_device' interface has several limitations: Issue#1. No way to determine when GPIO aggregator creation is complete. Issue#2. No way to retrieve errors when creating a GPIO aggregator. Issue#3. No way to trace a GPIO line of an aggregator back to its corresponding physical device. Issue#4. The 'new_device' echo does not indicate which virtual gpiochip<N> was created. Issue#5. No way to assign names to GPIO lines exported through an aggregator. Although Issue#1 to #3 could technically be resolved easily without configfs, using configfs offers a streamlined, modern, and extensible approach, especially since gpio-sim and gpio-virtuser already utilize configfs. This v7 patch series includes 9 patches: Patch#1: Reorder functions to prepare for configfs introduction. Patch#2: Unify function naming. Patch#3: Add gpio_aggregator_alloc() to reduce code duplication. Patch#4: Introduce basic configfs interface. Address Issue#1 to #5. Patch#5: Prepare for Patch#6. Patch#6: Expose devices created with sysfs to configfs. Patch#7: Suppress deferred probe for purely configfs-based aggregators. Patch#8: Documentation for the new configfs interface. Patch#9: Selftest for gpio-aggregator. N.B. This submission is based on commit 0af2f6be1b42 ("Linux 6.15-rc1"). v6->v7 changes: - Addressed feedback from Bartosz: * Unified function naming using gpio_aggregator_ prefix (except for GPIO forwarder implementations). * Replaced remaining raw mutex_lock/mutex_unlock with scoped_guard. * Ensured variables with __free() attribute are defined and assigned in a single statement. - Eliminated needless style inconsistencies across the new configfs attr .show() implementations by replacing scoped_guard with guard where possible, with no functional change. v5->v6 changes: - Addressed feedback from Bartosz: * Resolved issues spotted with lockdep and kasan. * Added kselftest for gpio-aggregator. - Fixed a memory leak in aggr_free_line() (missing kfree(line->name)). - Fixed a bug I mistakenly added in aggr_parse() (misplaced scnprintf()). - Eliminated a potential lock inversion deadlock by removing gpio_aggregator_lock acquisition in gpio_aggregator_remove_all(), which became unnecessary after the upstream commit 12f65d120350 ("gpio: aggregator: protect driver attr handlers against module unload"). v4->v5 changes: - Rebased off of the latest gpio/for-next, that includes the patch series: "Add synchronous fake device creation utility for GPIO drivers" (https://lore.kernel.org/all/20250221133501.2203897-1-koichiro.den@canonical.com/) v3->v4 changes: - Split off the introduction of gpio-pseudo.[ch] and conversions. - Reordered commits to place a fix commit first. - Squashed the trivial update for gpio-aggregator's conversion to gpio-pseudo into the primary commit "gpio: aggregator: introduce basic configfs interface" as it is only meaningful when combined. v2->v3 changes: - Addressed feedback from Bartosz: * Factored out the common mechanism for synchronizing platform device probe by adding gpio-pseudo.[ch]. * Renamed "_auto." prefix to "_sysfs." for auto-generated configfs entries corresponding to sysfs-created devices. * Squashed v2 Patch#3 into its predecessor. - Addressed feedback from Geert: * Factored out duplicate code in struct gpio_aggregator initialization by adding gpio_alloc()/gpio_free() functions. Note that v2 Patch#7 was dropped for other reasons as mentioned below, so aggr_free() in v3 is unrelated to the same-named function in v2. * Removed redundant parsing of gpio-line-names and unnecessary chip->names assignments; squashed v2 Patch#4 + v2 Patch#5 into v3 Patch#9. * Updated to use sysfs_emit(). * Updated Kconfig (select CONFIGFS_FS). * Fixed typos, coding style issues, missing const qualifiers, and other minor issues. - Resolved an issue that was spotted during v3 preparation. See Patch#2. - Reordered resource initialization order in gpio_aggregator_init() to both eliminate a potential race condition (as noted in the source code comment) and simplify the code. See Patch#8. This enabled: * Removal of v2 Patch#7. * Merging of aggr_unregister_lines() and aggr_free_lines() into a unified function. - Disabled 'delete_device' functionality for devices created via configfs for simplicity. It was mistakenly allowed in v2 and proved buggy. See Patch #8. RFC->v2 changes: - Addressed feedback from Bartosz: * Expose devices created with sysfs to configfs. * Drop 'num_lines' attribute. * Fix bugs and crashes. * Organize internal symbol prefixes more cleanly. - Split diffs for improved reviewability. - Update kernel doc to reflect the changes. v6: https://lore.kernel.org/all/20250315164123.1855142-1-koichiro.den@canonical.com/ v5: https://lore.kernel.org/all/20250224143134.3024598-1-koichiro.den@canonical.com/ v4: https://lore.kernel.org/all/20250217143531.541185-1-koichiro.den@canonical.com/ v3: https://lore.kernel.org/all/20250216125816.14430-1-koichiro.den@canonical.com/ v2: https://lore.kernel.org/all/20250203031213.399914-1-koichiro.den@canonical.com/ RFC (v1): https://lore.kernel.org/linux-gpio/20250129155525.663780-1-koichiro.den@canonical.com/T/#u Koichiro Den (9): gpio: aggregator: reorder functions to prepare for configfs introduction gpio: aggregator: unify function naming gpio: aggregator: add gpio_aggregator_{alloc,free}() gpio: aggregator: introduce basic configfs interface gpio: aggregator: rename 'name' to 'key' in gpio_aggregator_parse() gpio: aggregator: expose aggregator created via legacy sysfs to configfs gpio: aggregator: cancel deferred probe for devices created via configfs Documentation: gpio: document configfs interface for gpio-aggregator selftests: gpio: add test cases for gpio-aggregator .../admin-guide/gpio/gpio-aggregator.rst | 107 ++ drivers/gpio/Kconfig | 2 + drivers/gpio/gpio-aggregator.c | 1181 ++++++++++++++--- tools/testing/selftests/gpio/Makefile | 2 +- tools/testing/selftests/gpio/config | 1 + .../testing/selftests/gpio/gpio-aggregator.sh | 723 ++++++++++ 6 files changed, 1811 insertions(+), 205 deletions(-) create mode 100755 tools/testing/selftests/gpio/gpio-aggregator.sh