Hi Simon,
2015-01-24 0:50 GMT+09:00 Simon Glass <s...@chromium.org>: > > I tried to document the reasoning in the patches, but let me try to > expand a bit. Hopefully this can provoke further comments / > improvements. > > The main motivation for me was that buses want to set up the platform > data for their children before they are probed. In fact some children > may never be probed. For example a SPI bus wants to know the chip > select for each of its children. > > At present we have to hunt around in the device tree to figure out > which child is the right one, so we can probe it. Worse, the > children's drivers (e.g. cros_ec on a SPI bus) have to be involved in > setting themselves up. The device_probe_child() function was my > attempt to make this fit better, and it did work, but I was not happy > with it. You can see that from my unhappy comments in cros_ec, or SPI > flash probe, for example. > > The new approach makes buses easier to deal with as I hope you can > see. The 'bind' step is supposed to set up the entire basic framework > of the drivers at start-up. Everything should be visible in the tree > (the exception being buses which must be probed at run-time) but > nothing should be probed. Now, we are following that approach for > buses also. OK. I understand that this concept makes things much simpler, so Reviewed-by: Masahiro Yamada <yamad...@jp.panasonic.com> Perhaps, we can have a flag like DM_FLAG_ALLOC_PLATDATA_LATE: If this flag is set, platdata is allocated in device_probe(), not device_bind(). But, I think it might make things much more complicated and probably make you unhappy. I do not have a strong option about this. Let's go with your idea! If something does not go well, then we can come back here. > Re the disadvantages: > > - the per-child platform data for a bus is small, and we need not bind > devices which are disabled. So, a board should avoid having a lot of > enabled devices which are never used > - malloc() is very fast, it is the platform data setup that takes > time. I agree this slows things down. But currently it only affects > bus children, and only their basic information such as chip select. > > The use of ofdata_to_platdata() is stil confined to when the device is > actually probed. This helps to keep things fast in the common case > where we don't need the platform data earlier. > > I think we can refine this further, but what I have now feels a lot > cleaner to me. OK! I have done with a quick review of this series. I left some comments on some patches,but they are all minor issues. If you agree to fix them, please send v3. I am OK with the whole concept, so I guess we can get it in during this MW. Thanks! -- Best Regards Masahiro Yamada _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
