1 Managing the device tree data in U-Boot
2 =======================================
4 The 'fdt' command can be used to manipulate the device tree (DT) data
5 that is passed from U-Boot to Linux.
7 - 'fdt boardsetup' (which is automatically being run by the 'bootm'
8 command) will disable some device nodes according to environment
11 Environment setting disabled nodes
12 ---------------------------------------------
14 otg_mode=device usbotg
15 otg_mode=<UNSET> <both of the above> + usbphy
17 touchpanel=edt-ft5x06 ti,tsc2007
18 touchpanel=tsc2007 edt,edt-ft5x06
19 touchpanel=<UNSET> <both of the above>
21 Note: This command is automatically executed when booting Linux via
24 - 'fdt rm' and 'fdt mknode' can be used to remove/create additional nodes.
26 - 'fdt set' can be used to change properties or add new properties to
29 The whole DT data can be saved to and reloaded from the flash partition
30 'dtb' (or any other partition):
32 nand write.jffs2 ${fdtaddr} dtb ${fdtsize}
33 The predefined variable 'fdtsave' contains these commands as a macro
34 to facilitate the update of the 'dtb' partition with the currently
36 'run fdtsave' will achive the same as above commands.
38 (Re)Loading the DT data from flash:
39 nand read ${fdtaddr} dtb
41 Enabling/Disabling individual nodes in FDT:
42 Most device nodes in FDT use a property named 'status' that can be set
43 to either 'disabled' or 'okay' to disable or enable the device.
44 This property can be manipulated
45 fdt set /<path> status disabled
46 fdt set /<path> status okay
48 e.g.: fdt set /soc/aips-bus@02100000/ethernet@02188000 status disabled
49 will disable the ethernet interface on a TX6.
51 Refer to Linux/TX*-driver.pdf for a complete list of the device paths
52 for the individual TX modules.