1*75b57ecfSGrant LikelyWhat: /sys/firmware/devicetree/* 2*75b57ecfSGrant LikelyDate: November 2013 3*75b57ecfSGrant LikelyContact: Grant Likely <grant.likely@linaro.org> 4*75b57ecfSGrant LikelyDescription: 5*75b57ecfSGrant Likely When using OpenFirmware or a Flattened Device Tree to enumerate 6*75b57ecfSGrant Likely hardware, the device tree structure will be exposed in this 7*75b57ecfSGrant Likely directory. 8*75b57ecfSGrant Likely 9*75b57ecfSGrant Likely It is possible for multiple device-tree directories to exist. 10*75b57ecfSGrant Likely Some device drivers use a separate detached device tree which 11*75b57ecfSGrant Likely have no attachment to the system tree and will appear in a 12*75b57ecfSGrant Likely different subdirectory under /sys/firmware/devicetree. 13*75b57ecfSGrant Likely 14*75b57ecfSGrant Likely Userspace must not use the /sys/firmware/devicetree/base 15*75b57ecfSGrant Likely path directly, but instead should follow /proc/device-tree 16*75b57ecfSGrant Likely symlink. It is possible that the absolute path will change 17*75b57ecfSGrant Likely in the future, but the symlink is the stable ABI. 18*75b57ecfSGrant Likely 19*75b57ecfSGrant Likely The /proc/device-tree symlink replaces the devicetree /proc 20*75b57ecfSGrant Likely filesystem support, and has largely the same semantics and 21*75b57ecfSGrant Likely should be compatible with existing userspace. 22*75b57ecfSGrant Likely 23*75b57ecfSGrant Likely The contents of /sys/firmware/devicetree/ is a 24*75b57ecfSGrant Likely hierarchy of directories, one per device tree node. The 25*75b57ecfSGrant Likely directory name is the resolved path component name (node 26*75b57ecfSGrant Likely name plus address). Properties are represented as files 27*75b57ecfSGrant Likely in the directory. The contents of each file is the exact 28*75b57ecfSGrant Likely binary data from the device tree. 29