kernel/Documentation/userspace-api/gpio/sysfs.rst, branch linux-rolling-stable

docs: gpio: prefer pread(2) for interrupt reading

2024-06-10T07:37:52Z

In legacy sysfs GPIO, when using poll(2) on the sysfs GPIO value for state change awaiting, a subsequent read(2) is required for consuming the event, which the doc recommends the use of lseek(2) or close-and-reopen to reset the file offset afterwards. The recommendations however, require at least 2 syscalls to consume the event. Gladly, use of pread(2) require only 1 syscall for the consumption. Let's advertise this usage by prioritizing its placement. Signed-off-by: Huichun Feng Link: https://lore.kernel.org/r/20240609173728.2950808-1-foxhoundsk.tw@gmail.com Signed-off-by: Bartosz Golaszewski

Documentation: gpio: clarify sysfs line values are logical

2024-02-14T09:28:48Z

Clarify that line values are logical, not physical, by replacing high/low terminology with active/inactive. Signed-off-by: Kent Gibson Reviewed-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski

Documentation: gpio: update sysfs documentation to reference new chardev doc

2024-01-22T09:49:07Z

Update GPIO sysfs interface documentation to reference the new chardev document rather than gpio.h. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski

Documentation: gpio: move sysfs into an obsolete section

2024-01-22T09:49:06Z

The GPIO sysfs API is long obsolete, so highlight this even further by moving it into an obsolete APIs section in both the admin-guide and userspace-api books. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski