Messages in this thread | | | From | Warner Losh <> | Date | Mon, 12 Sep 2016 10:45:37 -0600 | Subject | Re: ARM, SoC: About the use DT-defined properties by 3rd-party drivers |
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On Mon, Sep 12, 2016 at 10:29 AM, Sebastian Frias <sf84@laposte.net> wrote: > Hi Warner, > > On 09/12/2016 04:26 PM, Warner Losh wrote: >> On Mon, Sep 12, 2016 at 8:01 AM, Mark Rutland <mark.rutland@arm.com> wrote: >>>> Since the question seems understood, do you have an example of other SoC's >>>> doing something similar? >>> >>> I do not have an example. I know that others are using DT for data >>> beyond what Linux or another OS requires, but it's my understanding that >>> that is typically in a separate DTB. >> >> Just to clarify: FreeBSD uses, for the most part, the DTB's that the >> 'vendor' ships, which is quite often the same ones included in Linux. >> There's some exceptions where the bindings weren't really hardware >> independent, or where the abstraction model was really Linux specific >> (for things like the HDMI stack). >> >> However, with the advent of overlays, one would think that a vendor >> could easily include an overlay with the DTB data for the devices they >> don't wish to, or cannot for other reasons release. It seems like the >> perfect mechanism to comply with the rules about inclusion of nodes in >> the DTS. Vendors are free to document these nodes and don't require >> the Linux kernel include them in the Documents directory to do so. >> There have been recent efforts to move this documentation to a third >> party to maintain. > > This is very interesting, do you have a more concrete example of such > usage?
Using overlays to layer in a proprietary device blob for a proprietary driver? No. I don't. It just seems like a natural solution. Do I have more examples where FreeBSD has to deviate because the DT is actually Linux specific and does a poor job of modeling the hardware and instead reflects the Linux driver model? I have plenty of those...
Warner
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