Hi all,
A change in kernel 6.2 ("gpio: Get rid of ARCH_NR_GPIOS (v2)") [1] resulted in
the GPIO chip base numbers changing on some architectures (x86, arm and arm64
were directly modified in that series).
This may cause issues with /etc/board.d/03_gpio_switches scripts as the GPIO
numbers will change when moving to the 6.6 kernel.
For example, on our (Traverse Ten64) board, the I2C GPIO expander (PCA953x)
used to be numbered from 368, now it is numbered from 640:
# Old
cat /sys/kernel/debug/gpio:
gpiochip4: GPIOs 368-383, parent: i2c/0-0076, 0-0076, can sleep:
gpiochip3: GPIOs 384-415, parent: platform/2330000.gpio, 2330000.gpio:
gpiochip2: GPIOs 416-447, parent: platform/2320000.gpio, 2320000.gpio:
gpiochip1: GPIOs 448-479, parent: platform/2310000.gpio, 2310000.gpio:
gpiochip0: GPIOs 480-511, parent: platform/2300000.gpio, 2300000.gpio:
# New
gpiochip0: GPIOs 512-543, parent: platform/2300000.gpio, 2300000.gpio:
gpiochip1: GPIOs 544-575, parent: platform/2310000.gpio, 2310000.gpio:
gpiochip2: GPIOs 576-607, parent: platform/2320000.gpio, 2320000.gpio:
gpiochip3: GPIOs 608-639, parent: platform/2330000.gpio, 2330000.gpio:
gpiochip4: GPIOs 640-655, parent: i2c/0-0076, 0-0076, can sleep:
I have tried to address this in my armsr/6.6 pull request, but I don't think
the solution is very elegant:
https://github.com/openwrt/openwrt/pull/14896/commits/b74da3cd82d69e99dda357e61cae9b32072bca80
(I still need to figure out uci migration of these settings between 6.1 and 6.6
systems)
sysfs GPIOs have also been deprecated for a while now, but from the mailing
list and GitHub archives, my understanding is that everyone was waiting for
libgpiod v2 to come out before migrating. (libgpiod v2 was released in August
2023).
I think kernel 6.6 may force this issue to be addressed. Should we try to
migrate to a new system (e.g libgpiod) or work out a more agnostic way to
discover GPIOs (sysfs, DTB etc.)?
Best Regards,
Matt
[1]
https://lore.kernel.org/lkml/cover.1662116601.git.christophe.le...@csgroup.eu/T/
_______________________________________________
openwrt-devel mailing list
openwrt-devel@lists.openwrt.org
https://lists.openwrt.org/mailman/listinfo/openwrt-devel
