Hi, On Tue, 31 Mar 2020 at 20:33, Ang, Chee Hong <[email protected]> wrote: > > > Hi Marek, > > > > On Wed, 11 Mar 2020 at 05:55, Marek Vasut <[email protected]> wrote: > > > > > > On 3/11/20 12:50 PM, Simon Glass wrote: > > > > Hi, > > > > > > Hi, > > > > > > > On Mon, 9 Mar 2020 at 02:22, <[email protected]> wrote: > > > >> > > > >> From: Chee Hong Ang <[email protected]> > > > >> > > > >> This commit (82de42fa14682d408da935adfb0f935354c5008f) calls > > > >> child's > > > >> ofdata_to_platdata() method before the parent is probed in dm core. > > > >> This has caused the driver no longer able to get the correct parent > > > >> clock's register base in the ofdata_to_platdata() method because > > > >> the parent clocks will only be probed after the child's > > > >> ofdata_to_platdata(). > > > >> To resolve this, the clock parent's register base will only be > > > >> retrieved by the child in probe() method instead of > > > >> ofdata_to_platdata(). > > > > > > > > I think one thing that is going on here is that DM allows ofdata to > > > > be read for a device before its parent devices have been read, but > > > > it requires that parent devices be probed before their children. > > > > > > This seems wrong. The clock driver should be able to instantiate > > > devices and read their ofdata without probing them. That is one of the > > > core design principles of the DM. > > > > That's a different question. Yes you can read ofdata without probing a > > device. > > That's why we have two methods. > > > > The point I am making is that at present there is no requirement that a > > parent's > > ofdata be read before a child's ofdata is read. But there is a requirement > > that a > > parent be probed before a child is probed. > > > > > > > > > The idea is that it should be possible to read the ofdata for a node > > > > without needing to have done so for parents. But perhaps this > > > > assumption is too brave? > > > > > > Why is it brave ? That's how it always was, the DT is already there, > > > so why wouldn't you be able to read it. > > > > That was my thinking too. But we are finding in a few situations that the > > child's > > ofdata depends on the parent's. For example, the parent may have a base > > address, or a range mapping, or something else that is needed for the child > > to > > correctly get its base address, etc. > > > > > > > > > I suspect we could change this, so that device_ofdata_to_platdata() > > > > first calls itself on its parent. > > > > > > > > I can think of various reasons why this change might be desirable. > > > > > > I think this is how it worked before already. > > > > Well effectively, yes, because ofdata and probe were joined together.
> Simon, do you have plan to fix this DM core issue ? I'm not sure it definitely should be changed. But I'll do a patch and see how it looks. Regards, Simon
