On Tue, 03 Apr 2018, Masahiro Yamada wrote: > 2018-04-03 17:03 GMT+09:00 Lee Jones <lee.jones@xxxxxxxxxx>: > > On Mon, 02 Apr 2018, Andrew Lunn wrote: > > > >> On Mon, Apr 02, 2018 at 10:21:01PM +0900, Masahiro Yamada wrote: > >> > 2018-04-02 21:04 GMT+09:00 Andrew Lunn <andrew@xxxxxxx>: > >> > >> The maintainer of DWC3, Felipe Balbi, requested to > >> > >> split the glue layer driver into small parts such as > >> > >> reset, regulator, phy, etc. > >> > > > >> > > What exactly did Felipe ask for? Did he ask that the patch be split > >> > > up, one patch per reset, regulator, phy etc? > >> > > >> > > >> > Yeah. That is what we understood from his comments. > >> > > >> > > >> > These are the feed-backs from him. > >> > > >> > https://lkml.org/lkml/2018/1/23/298 > >> > https://lkml.org/lkml/2018/1/24/352 > >> > >> > > Are all these resources used just by the DWC3? Or is it a true MFD, > >> > > multiple functions? > >> > > >> > I do not think this is a real MFD. > >> > > >> > This is a DWC3 glue layer, i.e. > >> > a collection of misc registers that control > >> > the DWC3 IP. > >> > > >> > > >> > Just splitting it into small pieces > >> > to use PHY, reset, regulator framework in Linux. > >> > > >> > Of course, the price of this approach > >> > is so cluttered Device Tree, > >> > honestly I do not like it much. > >> > >> This however the correct way to do this. You should have a phy driver, > >> and a regulator driver, and a reset driver. The DWC3 then uses > >> phandles to these drivers. > >> > >> How is the IO map area 65b00000 split up. Can you cleanly separate it > >> into sub areas, which do not overlap, so you have a sub-area for the > >> PHY driver, a sub-area for the regulator driver and a sub-area for the > >> reset area? If you can cleanly split it up, you don't need an MFD. If > >> however the registers are in overlapping areas, you do need an > >> MFD. The MFD core provides access to the registers, while its children > >> implement PHY, reset, regulator etc. > > > > This device certainly sounds like an MFD to me. > > > > Can you share the DT you've written please? > > > This is still under the internal review in Socionext, > but I attached it below FWIW. > > (I am not the author of this DT. > Written by Kunihiko Hayashi, > > Just skimming the driver, I guess it will be possible to flatten > the node structure by separating the register space into sub-areas. > If this is success, we do not the MFD driver. Sounds like a plan. Pretty sure this isn't really an MFD. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
