Currently the kernel only supplies an internal API for creating and destroying device tree overlays. For some boards vendor specific kernel modules exist for managing device tree overlays but they have not been upstreamed or upstreaming stalled. https://lkml.org/lkml/2015/6/12/624 https://lkml.org/lkml/2013/1/7/366 This patch series provides a sysfs based ABI for creation and destruction of dt overlays in /sys/firmware/devicetree/overlays. The following files are provided: load: This is a write only file. A string written to it is interpreted as the path to a flattened device tree overlay file. It is used to create and apply the contained overlays. loaded: This is a read only file. It provides the count of loaded overlays as a decimal number. unload: This is a write only file. If a positive number n is wrtten to this file the n most recent overlays are destroyed. If a negative number is written to this file all overlays are destroyed. Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx> version 2: change sysfs path to /sys/firmware/devicetree/overlays Fix errors indicated by kbuild robot: Add missing inline attribute to of_overlay_count in patch 1. Add 'select CONFIG_OF_EARLY_FLATTREE' to Kconfig in patch 2. Change unit test cases to check new functions of_overlay_count and of_overlay_destroy_last. Heinrich Schuchardt (4): of/overlay: add API function to count and pop last of/overlay: sysfs based ABI for dt overlays of/overlay: documentation for sysfs ABI of/overlay: test count and destroy_last .../ABI/testing/sysfs-firmware-devicetree-overlays | 24 +++ Documentation/devicetree/overlay-notes.txt | 7 +- drivers/of/Kconfig | 15 ++ drivers/of/Makefile | 2 + drivers/of/base.c | 1 + drivers/of/ov_sysfs.c | 223 +++++++++++++++++++++ drivers/of/overlay.c | 50 +++++ drivers/of/unittest.c | 15 +- include/linux/of.h | 12 ++ 9 files changed, 346 insertions(+), 3 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-devicetree-overlays create mode 100644 drivers/of/ov_sysfs.c -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
