Messages in this thread |  | | Date | Tue, 3 Apr 2018 09:03:35 +0100 | From | Lee Jones <> | Subject | Re: [Question] MFD driver that handles clocks/resets and populates child nodes |
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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@lunn.ch>: > > >> 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?
-- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
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