[PATCH RESEND 3/5] ARM: brcmstb: add misc. DT bindings for brcm, brcmstb
Arnd Bergmann
arnd at arndb.de
Sat Nov 23 15:45:29 EST 2013
On Saturday 23 November 2013, Marc C wrote:
> Hello Arnd,
>
> > Normally the "compatible" string identifies the register layout and
> > you keep the offsets in the device driver. Do you have strong reasons to do it
> > differently here?
>
> The register block that contains the reset registers also contains other
> “general purpose” registers, which can potentially scoot the positions
> of both “sw-master-reset” and “reset-source-enable”. Although we do
> stress to the H/W designers that consistency between chips is important,
> and that relative offsets of those registers should remain the same
> between chip revisions, there is no guarantee that this will happen.
>
> Now, rather than handling N revisions of the “sun-top-ctrl” register
> block at both the boot loader and kernel levels (N could get very large
> as we continue to port support for more chips), I feel that a more
> flexible solution would be to rely on the self-describing nature of the DT.
Ok, I see. I guess it's not even a uniform layout within the registers
then, right? Otherwise you could reference the number of the reset
register through the reset-api, but it gets kind of ugly when passing
the wrong value for a reset line touches a completely unrelated register
rather than "just" resetting the wrong device.
Arnd
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