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In case the nvmem DT node contains "wp-gpios" DT property, the device currently defaults to read-write and the force_ro sysfs attribute reads 0. Switch to the default read-only, which is both safer, and aligned with eMMC HW BOOT partition force_ro sysfs attribute behavior, which also defaults to read-only. The adjustment of nvmem->read_only value to read-only in case wp-gpios DT property is present must be done only after the device_add() got called because device_add() does internally call nvmem_bin_attr_get_umode(), which configures the permissions of 'nvmem' bin attr based on the value of nvmem->read_only that is only parsed from DT property 'read-only', without any adjustment. This way, if DT property 'read-only' is present, the 'nvmem' attribute is always read-only. Otherwise, if the device is writeable, then 'nvmem' attribute is writeable, and nvmem->read_only defaults to read-only, but can be switched to read-write at runtime via the 'force_ro' attribute. The updated behavior can be tested as follows: Current content: " $ cat /sys/bus/nvmem/devices/logging7/force_ro 1 $ hexdump -C /sys/bus/nvmem/devices/logging7/nvmem 00000000 66 6f 6f 0a ff ff ff ff " Write into default-read-only device: " $ echo bar > /sys/bus/nvmem/devices/logging7/nvmem bash: echo: write error: Operation not permitted $ cat /sys/bus/nvmem/devices/logging7/force_ro 1 " Unlock and write into device: " $ echo 0 > /sys/bus/nvmem/devices/logging7/force_ro $ cat /sys/bus/nvmem/devices/logging7/force_ro 0 $ echo bar > /sys/bus/nvmem/devices/logging7/nvmem $ hexdump -C /sys/bus/nvmem/devices/logging7/nvmem 00000000 62 61 72 0a ff ff ff ff " Relock and write into device, fails because device is read-only again: " $ echo 1 > /sys/bus/nvmem/devices/logging7/force_ro $ echo baz > /sys/bus/nvmem/devices/logging7/nvmem bash: echo: write error: Operation not permitted $ hexdump -C /sys/bus/nvmem/devices/logging7/nvmem 00000000 62 61 72 0a ff ff ff ff " Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> Signed-off-by: Marek Vasut <marex@nabladev.com> Signed-off-by: Srinivas Kandagatla <srini@kernel.org> Link: https://patch.msgid.link/20260530205333.117458-4-srini@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>