On Thu, May 19, 2016 at 10:45:56AM +0200, Jan Viktorin wrote: > Hello Rob, > > thank you for your opinion... > > On Wed, 18 May 2016 12:01:05 -0500 > Rob Herring <r...@kernel.org> wrote: > > > On Tue, May 17, 2016 at 11:22:19AM +0200, Jan Viktorin wrote: > > > Signed-off-by: Jan Viktorin <vikto...@rehivetech.com> > > > --- > > > .../devicetree/bindings/uio/uio_dmem_genirq.txt | 16 > > > ++++++++++++++++ > > > 1 file changed, 16 insertions(+) > > > create mode 100644 > > > Documentation/devicetree/bindings/uio/uio_dmem_genirq.txt > > > > DT describes h/w. UIO is not a h/w block, so this does not belong in DT. > > A UIO vs. kernel driver is purely a kernel decision which shouldn't > > require a DT change. > > I mostly agree and I don't say this is the very best solution... however, > it is quite a straightforward one. > > > > > The properties should be part of match data for a compatible string that > > True. But in case of probing from DT, where can I obtain those match data > from? I have to patch the kernel... and that is what I tried to avoid.
spi-dev is a similar situation and we put compatible strings (and therefore potentially match data) in the kernel. > With this patch set, you only modify your current device-tree (extend the > appropriate devices by "uio,...") and reboot with this new one. Generally speaking changing your kernel is as easy or easier than changing the DT. Rebooting is not a very good choice either when it could easily be a module unload/reload instead. > > needs them set. Or if they can be defined in a way that is actually a > > property of the h/w, then it would be acceptible. You'd still need to > > define compatible strings that the properties apply to. > > If you look at uio_pdrv_genirq you can see that it has already been extended > by > the module param "of_id". I.e. it is possible to specify the compatible > property > it would match when doing insmod. So, it is possible to bind it to any > platform > device described by the device tree. And thus, there is no way how to define a > list of compatible strings for it... (quite a long list, isn't it?) > > The same (of_id) can be done for uio_dmem_genirq, however, there is no way > how to > specify the amount of dynamic memory to be used for a specific device. For > me, it > makes sense to use DT to obtain those two properties saying "those devices > would > use this amount of memory and not more". > > Perhaps, another module param is a way to go here. Something like > of_dmem_count=2, > of_dmem_sizes=32k. Less flexible solution, however, if it is acceptable I'll > rewrite > the current one. No issue with doing that, though they are not OF parameters at that point. Rob
