On Sun, Apr 3, 2011 at 12:46 PM, Matt Sealey <m...@genesi-usa.com> wrote: > At the point where device tree specification and maintenance is done > in-kernel, device trees get very Linux-specific and very > Linux-driver-specific. Plenty of mistakes were made in the move to > flattened device trees on PowerPC which took too long to resolve.
This another good point. If you find yourself sticking Linux specific information (like module names) into the device tree, then something is wrong in the kernel, go fix the kernel. The device tree should only contain a generic description of the hardware that can be used by any operating system. On the other hand, device trees aren't a static solution. For example, they haven't come up with a generic mechanism for completely describing things like clock and power management domains. But let's figure out schemes for describing these problem areas and fix the device tree model. As more architectures utilize device trees these problem areas should get figured out and the issues will go away. So if you find yourself adding thousands of lines of board specific code to the kernel, something is probably wrong in the device tree generic hardware description, go fix it. This is an evolutionary process. Start off with selecting in-kernel device trees based on machine ID. Start off with describing the basic hardware in the device tree and remove the old kernel code that was building the description. Move on to device trees provided by the bootloader. After basic hardware description is converted move on to more complex areas like clock and power domains. A big effect of switching to device trees is to make kernel developers stop and think about generic solutions to problems instead of adding another 1,000 lines of one-off code to the kernel. The quicker ARM converts to device trees the easier the task will be. -- Jon Smirl jonsm...@gmail.com _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
