Josua Mayer 8b6b4ca42a net: rfkill: gpio: prevent value glitch during probe ... commit b2f750c3a8 upstream. When either reset- or shutdown-gpio have are initially deasserted, e.g. after a reboot - or when the hardware does not include pull-down, there will be a short toggle of both IOs to logical 0 and back to 1. It seems that the rfkill default is unblocked, so the driver should not glitch to output low during probe. It can lead e.g. to unexpected lte modem reconnect: [1] root@localhost:~# dmesg | grep "usb 2-1" [ 2.136124] usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd [ 21.215278] usb 2-1: USB disconnect, device number 2 [ 28.833977] usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd The glitch has been discovered on an arm64 board, now that device-tree support for the rfkill-gpio driver has finally appeared :). Change the flags for devm_gpiod_get_optional from GPIOD_OUT_LOW to GPIOD_ASIS to avoid any glitches. The rfkill driver will set the intended value during rfkill_sync_work. Fixes: 7176ba23f8 ("net: rfkill: add generic gpio rfkill driver") Signed-off-by: Josua Mayer <josua@solid-run.com> Link: https://lore.kernel.org/r/20231004163928.14609-1-josua@solid-run.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-10-25 11:58:57 +02:00
..
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
core.c	rfkill: make new event layout opt-in	2022-04-08 14:23:00 +02:00
input.c	rfkill: use DEFINE_SPINLOCK() for spinlock	2021-04-08 10:16:53 +02:00
rfkill-gpio.c	net: rfkill: gpio: prevent value glitch during probe	2023-10-25 11:58:57 +02:00
rfkill.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00