Hi Frank, Heinrich, > On Dec 22, 2016, at 21:00 , Frank Rowand <frowand.list@xxxxxxxxx> wrote: > > Hi Heinrich, > > On 12/20/16 11:04, Heinrich Schuchardt wrote: >> 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. > > This patch series follows a _somewhat_ similar approach to what > was first proposed two years ago, and does not address the > issues that were brought up at that time. See: > > From: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx> > Date: Wed, 3 Dec 2014 13:23:28 +0200 > Subject: [PATCH] OF: DT-Overlay configfs interface (v3) > > But just responding directly to the two year old issues would not > be a productive approach, since there has been a lot of subsequent > discussion on how to load overlays (you point to two of the many > threads above). The latest discussions are based on the concept > of describing the overlay attachment points as connectors. > > Please join in pushing the connectors discussion along to make > sure that it meets your needs. > I think it would be best if we focus on getting the configfs based loader to work. It is pretty similar to what Heinrich is proposing. > -Frank > Regards — Pantelis > >> >> 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 -- 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
