Commit 85b03b30 authored by Committed by Linus Walleij
Revert "gpiolib: Split GPIO flags parsing and GPIO configuration"
This reverts commit 923b93e4. Make sure consumers do not overwrite gpio flags for pins that have already been claimed. While adding support for gpio drivers to refuse a request using unsupported flags, the order of when the requested flag was checked and the new flags were applied was reversed to that consumers could overwrite flags for already requested gpios. This not only affects device-tree setups where two drivers could request the same gpio using conflicting configurations, but also allowed user space to clear gpio flags for already claimed pins simply by attempting to export them through the sysfs interface. By for example clearing the FLAG_ACTIVE_LOW flag this way, user space could effectively change the polarity of a signal. Reverting this change obviously prevents gpio drivers from doing sanity checks on the flags in their request callbacks. Fortunately only one recently added driver (gpio-tps65218 in v4.6) appears to do this, and a follow up patch could restore this functionality through a different interface. Cc: stable <firstname.lastname@example.org> # 4.4 Signed-off-by: Johan Hovold <email@example.com> Signed-off-by: Linus Walleij <firstname.lastname@example.org>
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