On Monday, November 14, 2016 11:51:15 AM CET Geert Uytterhoeven wrote: > On Thu, Nov 10, 2016 at 12:37 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Thursday, November 10, 2016 11:19:20 AM CET Geert Uytterhoeven wrote: > >> On Wed, Nov 9, 2016 at 5:55 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > >> > On Monday, October 31, 2016 12:30:55 PM CET Geert Uytterhoeven wrote: > >> >> - Use "renesas,prr" and "renesas,cccr" device nodes in DT if > >> >> available, else fall back to hardcoded addresses for compatibility > >> >> with existing DTBs, > > >> > It does seem wrong to have a device node for a specific register though. > >> > Shouldn't the node be for the block of registers that these are inside > >> > of? > >> > >> On R-Mobile APE6, R-Car Gen2 and Gen3, PRR is a lone register. > >> On R-Car Gen1, it's not even documented (and doesn't exist on all parts). > > > > It just seems odd to have it at address 0xff000044 when all the other > > devices are at page-aligned addresses. Do you mean that accessing > > 0xff000040 or 0xff000048 will result in a bus-level exception for a > > missing register and just 0xff000044 is actually valid for access, > > or is it just the only thing that is documented? > > For PRR, all other registers in the page read as all zeroes on all SoCs that > have it. So it really is a lone register. Ok. > >> On SH-Mobile/R-Mobile, CCCR may be part of the HPB/APB register block, which > >> we further don't touch at all. > >> On R-Car Gen2, it's not documented, but does exist. > > > > This is where the family names would come in handy ;-) I now have > > no idea which chip(s) you are referring to. > > SH/R-Mobile are r8a7740, r8a73a4, sh73a0. > R-Car Gen2 are r8a779[0-4]. > > > If you know the name of the register block, just put it into DT with > > that name. The driver can trivially add the right offset. > > CCCR is different. The amount of registers that read as non-zero depends a lot > on the actual SoC. > > HPB/APB is gonna need real DT bindings, which needs some more investigation. > Hence if you don't mind, I'd like to postpone that part, which only affects > the older SoCs. And I'll drop the "renesas,cccr" binding. > > For now, having revision detection for R-Car Gen3 (r8a779[56]) using PRR is > most urgent, as several drivers (e.g. HDMI, Ethernet, clocks, pinctrl) are > waiting for this support. So I'd like to have that dependency in v4.10. Ok, sounds good. > >> There is no SoC part number in the "renesas,prr" and "renesas,cccr" nodes. > >> Hence I always need to look at the root nodes. > > > > Not sure what that would protect you from. Could you have a renesas,cccr > > Looks like you forgot to finish your sentence? Yes, and I forgot what I was going to say there now. It's probably covered by what we discussed above. Arnd -- 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
