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Users currently have no standardized > > interface to enable or disable terminator state from userspace. > > > > This patch introduces the following: > > > > - EXPORT a new sysfs attribute `/sys/class/tty/*/mxpcie8250_terminator` > > to allow users to read or set the terminator state (enabled/disabled). > > - Implement both CPLD-based and GPIO-based paths depending on board model. > > - Track runtime terminator state in `struct mxpcie8250_port`. > > - Serialize CPLD modifications using a new `board_lock` spinlock. > > > > Example usage: > > > > # Enable terminator on ttyS* > > echo 1 > /sys/class/tty/ttyS*/mxpcie8250_terminator > > > > # Check current state > > cat /sys/class/tty/ttyS*/mxpcie8250_terminator > > enabled > > This introduces an ABI without documentation update. It's no go. Just to confirm my understanding — for any new user-visible ABI such as a sysfs attribute, the corresponding documentation under Documentation/ABI/ must be included in the same patch/series? --- Sincerely, Crescent Hsieh