On 06/11/12 08:40, Tabi Timur-B04825 wrote: > On Mon, Nov 5, 2012 at 2:40 PM, Grant Likely <[email protected]> > wrote: > >> Jane is building custom BeagleBone expansion boards called 'capes'. She >> can boot the system with a stock BeagleBoard device tree, but additional >> data is needed before a cape can be used. She could replace the FDT file >> used by U-Boot with one that contains the extra data, but she uses the >> same Linux system image regardless of the cape, and it is inconvenient >> to have to select a different device tree at boot time depending on the >> cape. > > What's wrong with having the boot loader detect the presence of the > Cape and update the device tree accordingly? We do this all the time > in U-Boot. Doing stuff like reading EEPROMs and testing for the > presence of hardware is easier in U-Boot than in Linux.
This is probably okay for some hardware, but doesn't work in the general case. Not all hardware is detectable, for example a cape which just adds a set of LEDs for GPIO pins. Also, some hardware might not easily be detectable without adding additional complexity to the boot loader. ~Ryan _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
