On 15:36-20210311, Jan Kiszka wrote: > On 11.03.21 15:21, Nishanth Menon wrote: > > On 15:14-20210311, Jan Kiszka wrote: > > > > [...] > > > >>> > >>> See [1] compare the compatibles against > >>> Documentation/devicetree/bindings -> I think you should describe what > >>> your hardware really is though. > >> > >> This SPI bus is routed to an Arduino connector. By default, userspace > >> (e.g. mraa) takes ownership and adds the desired logic for what is being > >> connected. We have no idea what shield or other extension the user adds, > >> though. > > > > overlays look like the right approach for variable systems like these. > > It is not exactly plug and play.. but it does provide a level of > > flexibility that is helpful. > > Yes, that's for extensions which have kernel drivers. The default model > here is userspace, though. Will add as a separate patch to our queue for > now. My colleagues did some checkups and pulled up a few thread on spidev of potential interests.. See: https://patchwork.kernel.org/project/spi-devel-general/patch/1427499742-26916-1-git-send-email-broonie@xxxxxxxxxx/ https://yurovsky.github.io/2016/10/07/spidev-linux-devices.html etc... I'd split the spidev node alone as an addendum indicate the checkpatch warning, describe the details and loop in spidev list, Mark, et.al. to discuss the direction. I am hoping we can get this resolved or get a direction for .13-rc1 But that said, I see some examples such as for i in `git grep ".compatible" drivers/spi/spidev.c|grep =|cut -d '=' -f2|cut -d ' ' -f2`; do git grep $i Documentation/devicetree/bindings/; done Documentation/devicetree/bindings/spi/spi-mux.yaml: compatible = "lineartechnology,ltc2488"; Documentation/devicetree/bindings/misc/ge-achc.txt:- compatible : Should be "ge,achc" Documentation/devicetree/bindings/misc/ge-achc.txt: compatible = "ge,achc"; Documentation/devicetree/bindings/misc/lwn-bk4.txt:- compatible : Should be "lwn,bk4" Documentation/devicetree/bindings/misc/lwn-bk4.txt: compatible = "lwn,bk4"; So, the shield could be hosting one of those say ge,achc or maybe lwn,bk4 ?- will probably be good to document the dts is for such a configuration, though it is possible that such a configuration might work for others? I agree with Mark that "dt should indicate specific hardware" and we should constraint the definition in such a scope? [...] > > > >> Are we talking about spidev here? Then let's drop that node, but I do > >> need to know how to describe spidev properly > > > > yes - the spidev is my problem. can you drop the node and repost? i cant > > locally modify and hope it works. > > > > Done. Thanks, I will try and pick up the v5 later today - need to redo my sanity checkups. -- Regards, Nishanth Menon Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D
